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* [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0
       [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
@ 2021-01-22 15:41 ` ANIMESH KUMAR SINHA
  2021-01-22 15:58 ` Thomas Huth
                   ` (6 subsequent siblings)
  7 siblings, 0 replies; 8+ messages in thread
From: ANIMESH KUMAR SINHA @ 2021-01-22 15:41 UTC (permalink / raw)
  To: qemu-devel

** Information type changed from Private Security to Public Security

** Also affects: ubuntu
   Importance: Undecided
       Status: New

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1912777

Title:
  KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0

Status in QEMU:
  New
Status in Ubuntu:
  New

Bug description:
  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.

  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.

  
  I did a bit of digging and extracted the kvm_run_exit to figure out whats going on.

  Please find 
  Stats from Qemu2.11:

  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a
  testcase)

  
  Stats For Qemu 4.0.0:

  VM_EXIT_UNKNOWN           : 0                                                                                                                                
  KVM_EXIT_EXCEPTION        : 0                                                                                                                                
  KVM_EXIT_IO               : 163729                                                                                                                           
  KVM_EXIT_HYPERCALL        : 0                                                                                                                                
  KVM_EXIT_DEBUG            : 0                                                                                                                                
  KVM_EXIT_HLT              : 0                                                                                                                                
  KVM_EXIT_MMIO             : 1094231                                                                                                                          
  KVM_EXIT_IRQ_WINDOW_OPEN  : 46                                                                                                                               
  KVM_EXIT_SHUTDOWN         : 0                                                                                                                                
  KVM_EXIT_FAIL_ENTRY       : 0                                                                                                                                
  KVM_EXIT_INTR             : 0                                                                                                                                
  KVM_EXIT_SET_TPR          : 0                                                                                                                                
  KVM_EXIT_TPR_ACCESS       : 0                                                                                                                                
  KVM_EXIT_S390_SIEIC       : 0                                                                                                                                
  KVM_EXIT_S390_RESET       : 0                                                                                                                                
  KVM_EXIT_DCR              : 0                                                                                                                                
  KVM_EXIT_NMI              : 0                                                                                                                                
  KVM_EXIT_INTERNAL_ERROR   : 0                                                                                                                                
  KVM_EXIT_OSI              : 0                                                                                                                                
  KVM_EXIT_PAPR_HCALL       : 0                                                                                                                                
  KVM_EXIT_S390_UCONTROL    : 0                                                                                                                                
  KVM_EXIT_WATCHDOG         : 0                                                                                                                                
  KVM_EXIT_S390_TSCH        : 0                                                                                                                                
  KVM_EXIT_EPR              : 0                                                                                                                                
  KVM_EXIT_SYSTEM_EVENT     : 0                                                                                                                                
  KVM_EXIT_S390_STSI        : 0                                                                                                                                
  KVM_EXIT_IOAPIC_EOI       : 464                                                                                                                              
  KVM_EXIT_HYPERV           : 0 

  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)


  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.

  Could someone from qemu community help me understand as to why the
  MMIO exits have increased in qemu4 ?

  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds

  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic

  
  Let me know incase more information is required .

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912777/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0
       [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
  2021-01-22 15:41 ` [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0 ANIMESH KUMAR SINHA
@ 2021-01-22 15:58 ` Thomas Huth
  2021-01-27  5:28 ` ANIMESH KUMAR SINHA
                   ` (5 subsequent siblings)
  7 siblings, 0 replies; 8+ messages in thread
From: Thomas Huth @ 2021-01-22 15:58 UTC (permalink / raw)
  To: qemu-devel

Can you provide a link to the test case that you used? Otherwise, can
you try to bisect the problem? Can you please also try with the latest
version of QEMU? v4.0 is rather old already.

** Information type changed from Public Security to Public

** Changed in: qemu
       Status: New => Incomplete

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1912777

Title:
  KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0

Status in QEMU:
  Incomplete
Status in Ubuntu:
  New

Bug description:
  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.

  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.

  
  I did a bit of digging and extracted the kvm_run_exit to figure out whats going on.

  Please find 
  Stats from Qemu2.11:

  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a
  testcase)

  
  Stats For Qemu 4.0.0:

  VM_EXIT_UNKNOWN           : 0                                                                                                                                
  KVM_EXIT_EXCEPTION        : 0                                                                                                                                
  KVM_EXIT_IO               : 163729                                                                                                                           
  KVM_EXIT_HYPERCALL        : 0                                                                                                                                
  KVM_EXIT_DEBUG            : 0                                                                                                                                
  KVM_EXIT_HLT              : 0                                                                                                                                
  KVM_EXIT_MMIO             : 1094231                                                                                                                          
  KVM_EXIT_IRQ_WINDOW_OPEN  : 46                                                                                                                               
  KVM_EXIT_SHUTDOWN         : 0                                                                                                                                
  KVM_EXIT_FAIL_ENTRY       : 0                                                                                                                                
  KVM_EXIT_INTR             : 0                                                                                                                                
  KVM_EXIT_SET_TPR          : 0                                                                                                                                
  KVM_EXIT_TPR_ACCESS       : 0                                                                                                                                
  KVM_EXIT_S390_SIEIC       : 0                                                                                                                                
  KVM_EXIT_S390_RESET       : 0                                                                                                                                
  KVM_EXIT_DCR              : 0                                                                                                                                
  KVM_EXIT_NMI              : 0                                                                                                                                
  KVM_EXIT_INTERNAL_ERROR   : 0                                                                                                                                
  KVM_EXIT_OSI              : 0                                                                                                                                
  KVM_EXIT_PAPR_HCALL       : 0                                                                                                                                
  KVM_EXIT_S390_UCONTROL    : 0                                                                                                                                
  KVM_EXIT_WATCHDOG         : 0                                                                                                                                
  KVM_EXIT_S390_TSCH        : 0                                                                                                                                
  KVM_EXIT_EPR              : 0                                                                                                                                
  KVM_EXIT_SYSTEM_EVENT     : 0                                                                                                                                
  KVM_EXIT_S390_STSI        : 0                                                                                                                                
  KVM_EXIT_IOAPIC_EOI       : 464                                                                                                                              
  KVM_EXIT_HYPERV           : 0 

  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)


  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.

  Could someone from qemu community help me understand as to why the
  MMIO exits have increased in qemu4 ?

  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds

  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic

  
  Let me know incase more information is required .

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912777/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0
       [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
  2021-01-22 15:41 ` [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0 ANIMESH KUMAR SINHA
  2021-01-22 15:58 ` Thomas Huth
@ 2021-01-27  5:28 ` ANIMESH KUMAR SINHA
  2021-02-02 10:42 ` ANIMESH KUMAR SINHA
                   ` (4 subsequent siblings)
  7 siblings, 0 replies; 8+ messages in thread
From: ANIMESH KUMAR SINHA @ 2021-01-27  5:28 UTC (permalink / raw)
  To: qemu-devel

The testcase is a rather a very basic one.
Doing a mmap on a pcie device and triggering a read and write operation on the Virtual Address, which would in-turn trigger transaction requests on the host device.

I understand that Qemu v4.0 may be and old one, but the issue is that
test case execution has become rather very slow with Qemu4.0.0 and the
only thing i could notice from using tracebacks were related with
increase in KVM_MMIO_EXIT when compared with Qemu2.11.0 version.

Can it be verified as to why the number of KVM_EXIT_MMIO has increased
drastically in qemu4 when compared to Qemu2.11.0 ?

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1912777

Title:
  KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0

Status in QEMU:
  Incomplete
Status in Ubuntu:
  New

Bug description:
  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.

  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.

  
  I did a bit of digging and extracted the kvm_run_exit to figure out whats going on.

  Please find 
  Stats from Qemu2.11:

  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a
  testcase)

  
  Stats For Qemu 4.0.0:

  VM_EXIT_UNKNOWN           : 0                                                                                                                                
  KVM_EXIT_EXCEPTION        : 0                                                                                                                                
  KVM_EXIT_IO               : 163729                                                                                                                           
  KVM_EXIT_HYPERCALL        : 0                                                                                                                                
  KVM_EXIT_DEBUG            : 0                                                                                                                                
  KVM_EXIT_HLT              : 0                                                                                                                                
  KVM_EXIT_MMIO             : 1094231                                                                                                                          
  KVM_EXIT_IRQ_WINDOW_OPEN  : 46                                                                                                                               
  KVM_EXIT_SHUTDOWN         : 0                                                                                                                                
  KVM_EXIT_FAIL_ENTRY       : 0                                                                                                                                
  KVM_EXIT_INTR             : 0                                                                                                                                
  KVM_EXIT_SET_TPR          : 0                                                                                                                                
  KVM_EXIT_TPR_ACCESS       : 0                                                                                                                                
  KVM_EXIT_S390_SIEIC       : 0                                                                                                                                
  KVM_EXIT_S390_RESET       : 0                                                                                                                                
  KVM_EXIT_DCR              : 0                                                                                                                                
  KVM_EXIT_NMI              : 0                                                                                                                                
  KVM_EXIT_INTERNAL_ERROR   : 0                                                                                                                                
  KVM_EXIT_OSI              : 0                                                                                                                                
  KVM_EXIT_PAPR_HCALL       : 0                                                                                                                                
  KVM_EXIT_S390_UCONTROL    : 0                                                                                                                                
  KVM_EXIT_WATCHDOG         : 0                                                                                                                                
  KVM_EXIT_S390_TSCH        : 0                                                                                                                                
  KVM_EXIT_EPR              : 0                                                                                                                                
  KVM_EXIT_SYSTEM_EVENT     : 0                                                                                                                                
  KVM_EXIT_S390_STSI        : 0                                                                                                                                
  KVM_EXIT_IOAPIC_EOI       : 464                                                                                                                              
  KVM_EXIT_HYPERV           : 0 

  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)


  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.

  Could someone from qemu community help me understand as to why the
  MMIO exits have increased in qemu4 ?

  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds

  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic

  
  Let me know incase more information is required .

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912777/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0
       [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
                   ` (2 preceding siblings ...)
  2021-01-27  5:28 ` ANIMESH KUMAR SINHA
@ 2021-02-02 10:42 ` ANIMESH KUMAR SINHA
  2021-02-02 12:57 ` ANIMESH KUMAR SINHA
                   ` (3 subsequent siblings)
  7 siblings, 0 replies; 8+ messages in thread
From: ANIMESH KUMAR SINHA @ 2021-02-02 10:42 UTC (permalink / raw)
  To: qemu-devel

Could someone update on this?

** Changed in: qemu
       Status: Incomplete => New

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1912777

Title:
  KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0

Status in QEMU:
  New
Status in Ubuntu:
  New

Bug description:
  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.

  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.

  
  I did a bit of digging and extracted the kvm_run_exit to figure out whats going on.

  Please find 
  Stats from Qemu2.11:

  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a
  testcase)

  
  Stats For Qemu 4.0.0:

  VM_EXIT_UNKNOWN           : 0                                                                                                                                
  KVM_EXIT_EXCEPTION        : 0                                                                                                                                
  KVM_EXIT_IO               : 163729                                                                                                                           
  KVM_EXIT_HYPERCALL        : 0                                                                                                                                
  KVM_EXIT_DEBUG            : 0                                                                                                                                
  KVM_EXIT_HLT              : 0                                                                                                                                
  KVM_EXIT_MMIO             : 1094231                                                                                                                          
  KVM_EXIT_IRQ_WINDOW_OPEN  : 46                                                                                                                               
  KVM_EXIT_SHUTDOWN         : 0                                                                                                                                
  KVM_EXIT_FAIL_ENTRY       : 0                                                                                                                                
  KVM_EXIT_INTR             : 0                                                                                                                                
  KVM_EXIT_SET_TPR          : 0                                                                                                                                
  KVM_EXIT_TPR_ACCESS       : 0                                                                                                                                
  KVM_EXIT_S390_SIEIC       : 0                                                                                                                                
  KVM_EXIT_S390_RESET       : 0                                                                                                                                
  KVM_EXIT_DCR              : 0                                                                                                                                
  KVM_EXIT_NMI              : 0                                                                                                                                
  KVM_EXIT_INTERNAL_ERROR   : 0                                                                                                                                
  KVM_EXIT_OSI              : 0                                                                                                                                
  KVM_EXIT_PAPR_HCALL       : 0                                                                                                                                
  KVM_EXIT_S390_UCONTROL    : 0                                                                                                                                
  KVM_EXIT_WATCHDOG         : 0                                                                                                                                
  KVM_EXIT_S390_TSCH        : 0                                                                                                                                
  KVM_EXIT_EPR              : 0                                                                                                                                
  KVM_EXIT_SYSTEM_EVENT     : 0                                                                                                                                
  KVM_EXIT_S390_STSI        : 0                                                                                                                                
  KVM_EXIT_IOAPIC_EOI       : 464                                                                                                                              
  KVM_EXIT_HYPERV           : 0 

  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)


  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.

  Could someone from qemu community help me understand as to why the
  MMIO exits have increased in qemu4 ?

  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds

  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic

  
  Let me know incase more information is required .

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912777/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0
       [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
                   ` (3 preceding siblings ...)
  2021-02-02 10:42 ` ANIMESH KUMAR SINHA
@ 2021-02-02 12:57 ` ANIMESH KUMAR SINHA
  2021-02-03 12:34 ` ANIMESH KUMAR SINHA
                   ` (2 subsequent siblings)
  7 siblings, 0 replies; 8+ messages in thread
From: ANIMESH KUMAR SINHA @ 2021-02-02 12:57 UTC (permalink / raw)
  To: qemu-devel

One observation i made was that adding qemu arguments "-nic none"
improved the testcase performance.

Does "-nic none" reduce KVM_EXIT_MMIO ?

Are there any other qemu arguments that can be used to improve qemu
overall performance ?

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1912777

Title:
  KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0

Status in QEMU:
  New
Status in Ubuntu:
  New

Bug description:
  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.

  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.

  
  I did a bit of digging and extracted the kvm_run_exit to figure out whats going on.

  Please find 
  Stats from Qemu2.11:

  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a
  testcase)

  
  Stats For Qemu 4.0.0:

  VM_EXIT_UNKNOWN           : 0                                                                                                                                
  KVM_EXIT_EXCEPTION        : 0                                                                                                                                
  KVM_EXIT_IO               : 163729                                                                                                                           
  KVM_EXIT_HYPERCALL        : 0                                                                                                                                
  KVM_EXIT_DEBUG            : 0                                                                                                                                
  KVM_EXIT_HLT              : 0                                                                                                                                
  KVM_EXIT_MMIO             : 1094231                                                                                                                          
  KVM_EXIT_IRQ_WINDOW_OPEN  : 46                                                                                                                               
  KVM_EXIT_SHUTDOWN         : 0                                                                                                                                
  KVM_EXIT_FAIL_ENTRY       : 0                                                                                                                                
  KVM_EXIT_INTR             : 0                                                                                                                                
  KVM_EXIT_SET_TPR          : 0                                                                                                                                
  KVM_EXIT_TPR_ACCESS       : 0                                                                                                                                
  KVM_EXIT_S390_SIEIC       : 0                                                                                                                                
  KVM_EXIT_S390_RESET       : 0                                                                                                                                
  KVM_EXIT_DCR              : 0                                                                                                                                
  KVM_EXIT_NMI              : 0                                                                                                                                
  KVM_EXIT_INTERNAL_ERROR   : 0                                                                                                                                
  KVM_EXIT_OSI              : 0                                                                                                                                
  KVM_EXIT_PAPR_HCALL       : 0                                                                                                                                
  KVM_EXIT_S390_UCONTROL    : 0                                                                                                                                
  KVM_EXIT_WATCHDOG         : 0                                                                                                                                
  KVM_EXIT_S390_TSCH        : 0                                                                                                                                
  KVM_EXIT_EPR              : 0                                                                                                                                
  KVM_EXIT_SYSTEM_EVENT     : 0                                                                                                                                
  KVM_EXIT_S390_STSI        : 0                                                                                                                                
  KVM_EXIT_IOAPIC_EOI       : 464                                                                                                                              
  KVM_EXIT_HYPERV           : 0 

  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)


  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.

  Could someone from qemu community help me understand as to why the
  MMIO exits have increased in qemu4 ?

  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds

  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic

  
  Let me know incase more information is required .

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912777/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0
       [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
                   ` (4 preceding siblings ...)
  2021-02-02 12:57 ` ANIMESH KUMAR SINHA
@ 2021-02-03 12:34 ` ANIMESH KUMAR SINHA
  2021-02-04  7:23 ` ANIMESH KUMAR SINHA
  2021-02-11 16:51 ` ANIMESH KUMAR SINHA
  7 siblings, 0 replies; 8+ messages in thread
From: ANIMESH KUMAR SINHA @ 2021-02-03 12:34 UTC (permalink / raw)
  To: qemu-devel

** Changed in: qemu
       Status: New => Opinion

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1912777

Title:
  KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0

Status in QEMU:
  Opinion
Status in Ubuntu:
  New

Bug description:
  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.

  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.

  
  I did a bit of digging and extracted the kvm_run_exit to figure out whats going on.

  Please find 
  Stats from Qemu2.11:

  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a
  testcase)

  
  Stats For Qemu 4.0.0:

  VM_EXIT_UNKNOWN           : 0                                                                                                                                
  KVM_EXIT_EXCEPTION        : 0                                                                                                                                
  KVM_EXIT_IO               : 163729                                                                                                                           
  KVM_EXIT_HYPERCALL        : 0                                                                                                                                
  KVM_EXIT_DEBUG            : 0                                                                                                                                
  KVM_EXIT_HLT              : 0                                                                                                                                
  KVM_EXIT_MMIO             : 1094231                                                                                                                          
  KVM_EXIT_IRQ_WINDOW_OPEN  : 46                                                                                                                               
  KVM_EXIT_SHUTDOWN         : 0                                                                                                                                
  KVM_EXIT_FAIL_ENTRY       : 0                                                                                                                                
  KVM_EXIT_INTR             : 0                                                                                                                                
  KVM_EXIT_SET_TPR          : 0                                                                                                                                
  KVM_EXIT_TPR_ACCESS       : 0                                                                                                                                
  KVM_EXIT_S390_SIEIC       : 0                                                                                                                                
  KVM_EXIT_S390_RESET       : 0                                                                                                                                
  KVM_EXIT_DCR              : 0                                                                                                                                
  KVM_EXIT_NMI              : 0                                                                                                                                
  KVM_EXIT_INTERNAL_ERROR   : 0                                                                                                                                
  KVM_EXIT_OSI              : 0                                                                                                                                
  KVM_EXIT_PAPR_HCALL       : 0                                                                                                                                
  KVM_EXIT_S390_UCONTROL    : 0                                                                                                                                
  KVM_EXIT_WATCHDOG         : 0                                                                                                                                
  KVM_EXIT_S390_TSCH        : 0                                                                                                                                
  KVM_EXIT_EPR              : 0                                                                                                                                
  KVM_EXIT_SYSTEM_EVENT     : 0                                                                                                                                
  KVM_EXIT_S390_STSI        : 0                                                                                                                                
  KVM_EXIT_IOAPIC_EOI       : 464                                                                                                                              
  KVM_EXIT_HYPERV           : 0 

  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)


  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.

  Could someone from qemu community help me understand as to why the
  MMIO exits have increased in qemu4 ?

  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds

  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic

  
  Let me know incase more information is required .

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912777/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0
       [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
                   ` (5 preceding siblings ...)
  2021-02-03 12:34 ` ANIMESH KUMAR SINHA
@ 2021-02-04  7:23 ` ANIMESH KUMAR SINHA
  2021-02-11 16:51 ` ANIMESH KUMAR SINHA
  7 siblings, 0 replies; 8+ messages in thread
From: ANIMESH KUMAR SINHA @ 2021-02-04  7:23 UTC (permalink / raw)
  To: qemu-devel

** Description changed:

  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.
  
  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.
  
+ I did a bit of digging and extracted the kvm_run_exit to figure out
+ whats going on.
  
- I did a bit of digging and extracted the kvm_run_exit to figure out whats going on.
- 
- Please find 
+ Please find
  Stats from Qemu2.11:
  
  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0
  
  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a testcase)
  
- 
  Stats For Qemu 4.0.0:
  
- VM_EXIT_UNKNOWN           : 0                                                                                                                                
- KVM_EXIT_EXCEPTION        : 0                                                                                                                                
- KVM_EXIT_IO               : 163729                                                                                                                           
- KVM_EXIT_HYPERCALL        : 0                                                                                                                                
- KVM_EXIT_DEBUG            : 0                                                                                                                                
- KVM_EXIT_HLT              : 0                                                                                                                                
- KVM_EXIT_MMIO             : 1094231                                                                                                                          
- KVM_EXIT_IRQ_WINDOW_OPEN  : 46                                                                                                                               
- KVM_EXIT_SHUTDOWN         : 0                                                                                                                                
- KVM_EXIT_FAIL_ENTRY       : 0                                                                                                                                
- KVM_EXIT_INTR             : 0                                                                                                                                
- KVM_EXIT_SET_TPR          : 0                                                                                                                                
- KVM_EXIT_TPR_ACCESS       : 0                                                                                                                                
- KVM_EXIT_S390_SIEIC       : 0                                                                                                                                
- KVM_EXIT_S390_RESET       : 0                                                                                                                                
- KVM_EXIT_DCR              : 0                                                                                                                                
- KVM_EXIT_NMI              : 0                                                                                                                                
- KVM_EXIT_INTERNAL_ERROR   : 0                                                                                                                                
- KVM_EXIT_OSI              : 0                                                                                                                                
- KVM_EXIT_PAPR_HCALL       : 0                                                                                                                                
- KVM_EXIT_S390_UCONTROL    : 0                                                                                                                                
- KVM_EXIT_WATCHDOG         : 0                                                                                                                                
- KVM_EXIT_S390_TSCH        : 0                                                                                                                                
- KVM_EXIT_EPR              : 0                                                                                                                                
- KVM_EXIT_SYSTEM_EVENT     : 0                                                                                                                                
- KVM_EXIT_S390_STSI        : 0                                                                                                                                
- KVM_EXIT_IOAPIC_EOI       : 464                                                                                                                              
- KVM_EXIT_HYPERV           : 0 
+ VM_EXIT_UNKNOWN           : 0
+ KVM_EXIT_EXCEPTION        : 0
+ KVM_EXIT_IO               : 163729
+ KVM_EXIT_HYPERCALL        : 0
+ KVM_EXIT_DEBUG            : 0
+ KVM_EXIT_HLT              : 0
+ KVM_EXIT_MMIO             : 1094231
+ KVM_EXIT_IRQ_WINDOW_OPEN  : 46
+ KVM_EXIT_SHUTDOWN         : 0
+ KVM_EXIT_FAIL_ENTRY       : 0
+ KVM_EXIT_INTR             : 0
+ KVM_EXIT_SET_TPR          : 0
+ KVM_EXIT_TPR_ACCESS       : 0
+ KVM_EXIT_S390_SIEIC       : 0
+ KVM_EXIT_S390_RESET       : 0
+ KVM_EXIT_DCR              : 0
+ KVM_EXIT_NMI              : 0
+ KVM_EXIT_INTERNAL_ERROR   : 0
+ KVM_EXIT_OSI              : 0
+ KVM_EXIT_PAPR_HCALL       : 0
+ KVM_EXIT_S390_UCONTROL    : 0
+ KVM_EXIT_WATCHDOG         : 0
+ KVM_EXIT_S390_TSCH        : 0
+ KVM_EXIT_EPR              : 0
+ KVM_EXIT_SYSTEM_EVENT     : 0
+ KVM_EXIT_S390_STSI        : 0
+ KVM_EXIT_IOAPIC_EOI       : 464
+ KVM_EXIT_HYPERV           : 0
  
  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)
- 
  
  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.
  
  Could someone from qemu community help me understand as to why the MMIO
  exits have increased in qemu4 ?
  
  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds
  
  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic
  
- 
  Let me know incase more information is required .

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1912777

Title:
  KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0

Status in QEMU:
  Opinion
Status in Ubuntu:
  New

Bug description:
  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.

  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.

  I did a bit of digging and extracted the kvm_run_exit to figure out
  whats going on.

  Please find
  Stats from Qemu2.11:

  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a
  testcase)

  Stats For Qemu 4.0.0:

  VM_EXIT_UNKNOWN           : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 163729
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 1094231
  KVM_EXIT_IRQ_WINDOW_OPEN  : 46
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 464
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)

  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.

  Could someone from qemu community help me understand as to why the
  MMIO exits have increased in qemu4 ?

  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds

  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic

  Let me know incase more information is required .

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1912777/+subscriptions


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0
       [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
                   ` (6 preceding siblings ...)
  2021-02-04  7:23 ` ANIMESH KUMAR SINHA
@ 2021-02-11 16:51 ` ANIMESH KUMAR SINHA
  7 siblings, 0 replies; 8+ messages in thread
From: ANIMESH KUMAR SINHA @ 2021-02-11 16:51 UTC (permalink / raw)
  To: qemu-devel

** Also affects: qemu (Ubuntu)
   Importance: Undecided
       Status: New

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1912777

Title:
  KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0

Status in QEMU:
  Opinion
Status in Ubuntu:
  New
Status in qemu package in Ubuntu:
  New

Bug description:
  I was able to generate trace dump in Qemu for kvm_run_exit event in both QEMU 2.11.0 and QEMU 4.0.0
  From the trace i noticed that the number of KVM_KXIT_MMIO calls has increased alot and is causing delay in testcase execution.

  I executed same testcase from Qemu 2.11 and Qemu4.
  Inside Virtual machine when using qemu 2.11 testcase got completed in 11 seconds
  but the same testcase when executed on Qemu 4.0.0 got executed in 26 seconds.

  I did a bit of digging and extracted the kvm_run_exit to figure out
  whats going on.

  Please find
  Stats from Qemu2.11:

  KVM_EXIT_UNKNOWN          : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 182513
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 216701
  KVM_EXIT_IRQ_WINDOW_OPEN  : 0
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 0
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 399214  (Total in Qemu 2.11 for a
  testcase)

  Stats For Qemu 4.0.0:

  VM_EXIT_UNKNOWN           : 0
  KVM_EXIT_EXCEPTION        : 0
  KVM_EXIT_IO               : 163729
  KVM_EXIT_HYPERCALL        : 0
  KVM_EXIT_DEBUG            : 0
  KVM_EXIT_HLT              : 0
  KVM_EXIT_MMIO             : 1094231
  KVM_EXIT_IRQ_WINDOW_OPEN  : 46
  KVM_EXIT_SHUTDOWN         : 0
  KVM_EXIT_FAIL_ENTRY       : 0
  KVM_EXIT_INTR             : 0
  KVM_EXIT_SET_TPR          : 0
  KVM_EXIT_TPR_ACCESS       : 0
  KVM_EXIT_S390_SIEIC       : 0
  KVM_EXIT_S390_RESET       : 0
  KVM_EXIT_DCR              : 0
  KVM_EXIT_NMI              : 0
  KVM_EXIT_INTERNAL_ERROR   : 0
  KVM_EXIT_OSI              : 0
  KVM_EXIT_PAPR_HCALL       : 0
  KVM_EXIT_S390_UCONTROL    : 0
  KVM_EXIT_WATCHDOG         : 0
  KVM_EXIT_S390_TSCH        : 0
  KVM_EXIT_EPR              : 0
  KVM_EXIT_SYSTEM_EVENT     : 0
  KVM_EXIT_S390_STSI        : 0
  KVM_EXIT_IOAPIC_EOI       : 464
  KVM_EXIT_HYPERV           : 0

  KVM_RUN_EXIT              : 1258470 (Total in qemu 4.0.0 for same
  testcase)

  From above analysis i found that the number of KVM_EXIT_MMIO has
  increased by 4.x.

  Could someone from qemu community help me understand as to why the
  MMIO exits have increased in qemu4 ?

  The results i obtained are after running same testcase.
  On Qemu2.11 testcase gets completed in : 11seconds
  on Qemu4.11 testcase gets completed in : 26 seconds

  VM Qcow2 used in Ubuntu 16.04
  VM kernel OS is : 4.4 generic

  Let me know incase more information is required .

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^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2021-02-11 17:11 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <161131847021.10154.14606822070729811950.malonedeb@gac.canonical.com>
2021-01-22 15:41 ` [Bug 1912777] Re: KVM_EXIT_MMIO has increased in Qemu4.0.0 when compared to Qemu 2.11.0 ANIMESH KUMAR SINHA
2021-01-22 15:58 ` Thomas Huth
2021-01-27  5:28 ` ANIMESH KUMAR SINHA
2021-02-02 10:42 ` ANIMESH KUMAR SINHA
2021-02-02 12:57 ` ANIMESH KUMAR SINHA
2021-02-03 12:34 ` ANIMESH KUMAR SINHA
2021-02-04  7:23 ` ANIMESH KUMAR SINHA
2021-02-11 16:51 ` ANIMESH KUMAR SINHA

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