Re: swiotlb=force in Konrad's xen-pcifront-0.8.2 pvops domU kernel with PCI passthrough

[Dante Cinco <dantecinco@gmail.com>]

On Fri, Nov 19, 2010 at 9:10 AM, Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> On 11/18/2010 11:35 AM, Dante Cinco wrote:
>> I mentioned earlier in an previous post to this thread that I'm able
>> to apply Dulloor's xenoprofile patch to the dom0 kernel but not the
>> domU kernel. So I can't do active-domain profiling but I'm able to do
>> passive-domain profiling but I don't know how reliable the results are
>> since it shows pvclock_clocksource_read as the top consumer of CPU
>> cycles at 28%.
>
> Is rdtsc emulation on?  (I forget what the incantation is for that now.)

How do I check if rdtsc emulation is on? Does 'xm debug-keys s' do it?

(XEN) *** Serial input -> Xen (type 'CTRL-a' three times to switch
input to DOM0)
(XEN) TSC marked as reliable, warp = 0 (count=2)
(XEN) dom1: mode=0,ofs=0xca6f68770,khz=2666017,inc=1
(XEN) No domains have emulated TSC

I'm using xen-unstable-4.1 (22388:87f248de5230).

- Dante

>
>    J
>
>> CPU: Intel Architectural Perfmon, speed 2665.98 MHz (estimated)
>> Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a
>> unit mask of 0x00 (No unit mask) count 100000
>> samples  %        image name               app name                 symbol name
>> 918089   27.9310
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           pvclock_clocksource_read
>> 217811    6.6265  domain1-modules          domain1-modules
>> /domain1-modules
>> 188327    5.7295  vmlinux-2.6.32.25-pvops-stable-dom0-5.7.dcinco-debug
>> vmlinux-2.6.32.25-pvops-stable-dom0-5.7.dcinco-debug
>> mutex_spin_on_owner
>> 186684    5.6795
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           __xen_spin_lock
>> 149514    4.5487
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           __write_lock_failed
>> 123278    3.7505
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           __kernel_text_address
>> 122906    3.7392
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           xen_spin_unlock
>> 90903     2.7655
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           __spin_time_accum
>> 85880     2.6127
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           __module_address
>> 75223     2.2885
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           print_context_stack
>> 66778     2.0316
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           __module_text_address
>> 57389     1.7459
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           is_module_text_address
>> 47282     1.4385  xen-syms-4.1-unstable    domain1-xen
>> syscall_enter
>> 47219     1.4365
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           prio_tree_insert
>> 46495     1.4145  vmlinux-2.6.32.25-pvops-stable-dom0-5.7.dcinco-debug
>> vmlinux-2.6.32.25-pvops-stable-dom0-5.7.dcinco-debug
>> pvclock_clocksource_read
>> 44501     1.3539
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           prio_tree_left
>> 32482     0.9882
>> vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>> domain1-kernel           native_read_tsc
>>
>> I ran oprofile (0.9.5 with xenoprofile patch) for 20 seconds while the
>> I/Os were running. Here's the command I used:
>>
>> opcontrol --start --xen=/boot/xen-syms-4.1-unstable
>> --vmlinux=/boot/vmlinux-2.6.32.25-pvops-stable-dom0-5.7.dcinco-debug
>> --passive-domains=1
>> --passive-images=/boot/vmlinux-2.6.36-rc7-pvops-kpcif-08-2-domu-5.11.dcinco-debug
>>
>> I had to remove dom0_max_vcpus=1 (but kept dom0_vcpus_pin=true) in the
>> Xen command line. Otherwise, oprofile only gives the samples from
>> CPU0.
>>
>> I'm going to try perf next.
>>
>> - Dante
>>
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>>
>
>