XP smp using a lot of CPU

XP smp using a lot of CPU

[Ross Boylan]

I just installed XP into a new VM, specifying -smp 2 for the machine.
According to top, it's using nearly 200% of a cpu even when I'm not
doing anything.

Is this real CPU useage, or just a reporting problem (just as my disk
image is big according to ls, but isn't really)?

If it's real, is there anything I can do about it?

kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon chips; 32
bit version of XP pro installed, now fully patched (including the
Windows Genuine Advantage stuff, though I cancelled it when it wanted to
run).  

Task manager in XP shows virtually no CPU useage.

Please cc me on responses.

Thanks for any assistance.
-- 
Ross Boylan                                      wk:  (415) 514-8146
185 Berry St #5700                               ross@biostat.ucsf.edu
Dept of Epidemiology and Biostatistics           fax: (415) 514-8150
University of California, San Francisco
San Francisco, CA 94107-1739                     hm:  (415) 550-1062

Re: XP smp using a lot of CPU

[Elias Probst]

[-- Attachment #1: Type: text/plain, Size: 1119 bytes --]

Hi,

I'm facing the same problem here.

A Windows XP (SP3 + all current Updates) which uses constantly ~95% CPU on 
each core.

I've already tried:
- Using only 1 core
- Replacing the HAL in Windows
- Using another KVM version
- Using different timer options for KVM

I'm currently on KVM-85 where the problem still exists.

Regards, Elias P.


On Wednesday 13 May 2009 02:41:38 Ross Boylan wrote:
> I just installed XP into a new VM, specifying -smp 2 for the machine.
> According to top, it's using nearly 200% of a cpu even when I'm not
> doing anything.
>
> Is this real CPU useage, or just a reporting problem (just as my disk
> image is big according to ls, but isn't really)?
>
> If it's real, is there anything I can do about it?
>
> kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon chips; 32
> bit version of XP pro installed, now fully patched (including the
> Windows Genuine Advantage stuff, though I cancelled it when it wanted to
> run).
>
> Task manager in XP shows virtually no CPU useage.
>
> Please cc me on responses.
>
> Thanks for any assistance.


[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 198 bytes --]

Re: XP smp using a lot of CPU

[Avi Kivity]

Ross Boylan wrote:
> I just installed XP into a new VM, specifying -smp 2 for the machine.
> According to top, it's using nearly 200% of a cpu even when I'm not
> doing anything.
>
> Is this real CPU useage, or just a reporting problem (just as my disk
> image is big according to ls, but isn't really)?
>
> If it's real, is there anything I can do about it?
>
> kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon chips; 32
> bit version of XP pro installed, now fully patched (including the
> Windows Genuine Advantage stuff, though I cancelled it when it wanted to
> run).  
>
> Task manager in XP shows virtually no CPU useage.
>
> Please cc me on responses.
>
>   

I'm guessing Windows uses a pio port to sleep, which kvm doesn't 
support.  Can you provide kvm_stat output?

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

Re: XP smp using a lot of CPU

[Erik Rull]

Hi all,

very very interesting.

I have a similar problem but the other way round.
If my XP runs up tp 100% CPU usage "top" on the linux host reports "only" 
33% cpu usage. I would expect around 50% because I only provide one core 
for the guest. I already increased the process priority of qemu and the io 
priority, nothing helped. The rest of the CPU is nearly idle, no excessive 
disk access this time :-)

Any Idea what this could be?

Best regards,

Erik


Ross Boylan wrote:
> I just installed XP into a new VM, specifying -smp 2 for the machine.
> According to top, it's using nearly 200% of a cpu even when I'm not
> doing anything.
> 
> Is this real CPU useage, or just a reporting problem (just as my disk
> image is big according to ls, but isn't really)?
> 
> If it's real, is there anything I can do about it?
> 
> kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon chips; 32
> bit version of XP pro installed, now fully patched (including the
> Windows Genuine Advantage stuff, though I cancelled it when it wanted to
> run).  
> 
> Task manager in XP shows virtually no CPU useage.
> 
> Please cc me on responses.
> 
> Thanks for any assistance.

XP smp using a lot of CPU

[Johannes Schlatow]

I had a similar problem some weeks ago. Finally I found out that my VM
running WinXP was working on a non-acpi system (maybe I started kvm
with -no-acpi option during the installation). In the Device Manager
there has to be the entry Computer->"ACPI Multiprocessor PC".
Otherwise the VM produced 100% real cpu load on my machines (the fans
were running on highest speed level).
I just started the WinXP installation in repair mode and this did fix
the problem.

I hope this helps!

regards
  Johannes

On Wed, May 13, 2009 at 2:41 AM, Ross Boylan <ross@biostat.ucsf.edu> wrote:
>
> I just installed XP into a new VM, specifying -smp 2 for the machine.
> According to top, it's using nearly 200% of a cpu even when I'm not
> doing anything.
>
> Is this real CPU useage, or just a reporting problem (just as my disk
> image is big according to ls, but isn't really)?
>
> If it's real, is there anything I can do about it?
>
> kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon chips; 32
> bit version of XP pro installed, now fully patched (including the
> Windows Genuine Advantage stuff, though I cancelled it when it wanted to
> run).
>
> Task manager in XP shows virtually no CPU useage.
>
> Please cc me on responses.
>
> Thanks for any assistance.
> --
> Ross Boylan                                      wk:  (415) 514-8146
> 185 Berry St #5700                               ross@biostat.ucsf.edu
> Dept of Epidemiology and Biostatistics           fax: (415) 514-8150
> University of California, San Francisco
> San Francisco, CA 94107-1739                     hm:  (415) 550-1062
>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: XP smp using a lot of CPU

[Kevin Shanahan]

On Wed, May 13, 2009 at 09:56:18AM +0300, Avi Kivity wrote:
> Ross Boylan wrote:
>> I just installed XP into a new VM, specifying -smp 2 for the machine.
>> According to top, it's using nearly 200% of a cpu even when I'm not
>> doing anything.
>>
>> Is this real CPU useage, or just a reporting problem (just as my disk
>> image is big according to ls, but isn't really)?
>>
>> If it's real, is there anything I can do about it?
>>
>> kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon chips; 32
>> bit version of XP pro installed, now fully patched (including the
>> Windows Genuine Advantage stuff, though I cancelled it when it wanted to
>> run).  
>>
>> Task manager in XP shows virtually no CPU useage.
>>
>> Please cc me on responses.
>>
>>   
>
> I'm guessing Windows uses a pio port to sleep, which kvm doesn't  
> support.  Can you provide kvm_stat output?

Could this be what has happened to Windows 2000 as well? (kvm-Bugs-2314737)

Task manager in the guest shows both CPUs idle, but on the host it
shows 200% CPU almost constantly.

ucwb-0119:/home/kmshanah/kvm/kvm-85# ./kvm_stat -1
efer_reload                    0         0
exits                 5454894602      4839
fpu_reload               5311150         5
halt_exits                200719         1
halt_wakeup               200218         1
host_state_reload     1951410204      1869
hypercalls                     0         0
insn_emulation        1391377570      1393
insn_emulation_fail           52         0
invlpg                  92034019         1
io_exits              1042421930       694
irq_exits             1545221935      1874
irq_injections         450100320       448
irq_window             225291775       245
kvm_request_irq                0         0
largepages                     0         0
mmio_exits                484805         0
mmu_cache_miss          26346459         4
mmu_flooded             21532314         4
mmu_pde_zapped            886970         0
mmu_pte_updated         52882039         4
mmu_pte_write           70044961         6
mmu_recycled                1102         0
mmu_shadow_zapped       26384127         4
mmu_unsync                  7671         0
mmu_unsync_global              0         0
nmi_injections                 0         0
nmi_window                     0         0
pf_fixed               421444565       167
pf_guest                34545643         1
remote_tlb_flush       125039581         9
request_nmi                    0         0
signal_exits                   1         0
tlb_flush              749126829       284

Regards,
Kevin.

Re: XP smp using a lot of CPU

[Ross Boylan]

On Thu, 2009-05-14 at 12:19 +0200, Johannes Schlatow wrote:
> I had a similar problem some weeks ago. Finally I found out that my VM
> running WinXP was working on a non-acpi system (maybe I started kvm
> with -no-acpi option during the installation). In the Device Manager
> there has to be the entry Computer->"ACPI Multiprocessor PC".
> Otherwise the VM produced 100% real cpu load on my machines (the fans
> were running on highest speed level).
> I just started the WinXP installation in repair mode and this did fix
> the problem.
> 
> I hope this helps!
> 
> regards
>   Johannes
That may be it: I was running with -no-acpi.  Various docs recommended
this for Windows performance, but your comment reminded me that acpi is
(I think) required for multiprocessors.

I'll be in where I can check on this later today.

Thanks.
Ross
> 
> On Wed, May 13, 2009 at 2:41 AM, Ross Boylan <ross@biostat.ucsf.edu>
> wrote:
>         I just installed XP into a new VM, specifying -smp 2 for the
>         machine.
>         According to top, it's using nearly 200% of a cpu even when
>         I'm not
>         doing anything.
>         
>         Is this real CPU useage, or just a reporting problem (just as
>         my disk
>         image is big according to ls, but isn't really)?
>         
>         If it's real, is there anything I can do about it?
>         
>         kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon
>         chips; 32
>         bit version of XP pro installed, now fully patched (including
>         the
>         Windows Genuine Advantage stuff, though I cancelled it when it
>         wanted to
>         run).
>         
>         Task manager in XP shows virtually no CPU useage.
>         
>         Please cc me on responses.
>         
>         Thanks for any assistance.
>         --
>         Ross Boylan                                      wk:  (415)
>         514-8146
>         185 Berry St #5700
>         ross@biostat.ucsf.edu
>         Dept of Epidemiology and Biostatistics           fax: (415)
>         514-8150
>         University of California, San Francisco
>         San Francisco, CA 94107-1739                     hm:  (415)
>         550-1062
>         
>         --
>         To unsubscribe from this list: send the line "unsubscribe kvm"
>         in
>         the body of a message to majordomo@vger.kernel.org
>         More majordomo info at
>          http://vger.kernel.org/majordomo-info.html
>         
> 

Re: XP smp using a lot of CPU

[Ross Boylan]

On Wed, 2009-05-13 at 09:56 +0300, Avi Kivity wrote:
> Ross Boylan wrote:
> > I just installed XP into a new VM, specifying -smp 2 for the machine.
> > According to top, it's using nearly 200% of a cpu even when I'm not
> > doing anything.
> >
> > Is this real CPU useage, or just a reporting problem (just as my disk
> > image is big according to ls, but isn't really)?
> >
> > If it's real, is there anything I can do about it?
> >
> > kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon chips; 32
> > bit version of XP pro installed, now fully patched (including the
> > Windows Genuine Advantage stuff, though I cancelled it when it wanted to
> > run).  
> >
> > Task manager in XP shows virtually no CPU useage.
> >
> > Please cc me on responses.
> >
> >   
> 
> I'm guessing Windows uses a pio port to sleep, which kvm doesn't 
> support.  Can you provide kvm_stat output?
markov:~# kvm_stat -1
efer_reload                    0         0
exits                    9921384       566
fpu_reload                267970         0
halt_exits                     1         0
halt_wakeup                    3         0
host_state_reload        4026050        17
hypercalls                     0         0
insn_emulation           1329455         0
insn_emulation_fail          154         0
invlpg                    176773         0
io_exits                 3818270         0
irq_exits                1434046       566
irq_injections            326730         0
irq_window                164827         0
largepages                     0         0
mmio_exits                 35892         0
mmu_cache_miss             29760         0
mmu_flooded                19908         0
mmu_pde_zapped             15557         0
mmu_pte_updated            82088         0
mmu_pte_write              97990         0
mmu_recycled                   0         0
mmu_shadow_zapped          43276         0
mmu_unsync                   891         0
mmu_unsync_global              0         0
nmi_injections                 0         0
nmi_window                     0         0
pf_fixed                 1231164         0
pf_guest                  276083         0
remote_tlb_flush          115606         0
request_irq                    0         0
request_nmi                    0         0
signal_exits                   5         0
tlb_flush                 960198         0

This is with the VM displaying the XP "It is now safe to turn off your
computer".  CPU remains about 200% from kvm.  Invoked with
sudo vdeq kvm -net nic,vlan=1,macaddr=52:54:a0:12:01:00 \
    -net vde,vlan=1,sock=/var/run/vde2/tap0.ctl \
    -std-vga -hda XP.raw \
    -boot c \
    -soundhw es1370 -localtime -no-acpi  -m 1G -smp 2

Next I'll trying fiddling with acpi.

-- 
Ross Boylan                                      wk:  (415) 514-8146
185 Berry St #5700                               ross@biostat.ucsf.edu
Dept of Epidemiology and Biostatistics           fax: (415) 514-8150
University of California, San Francisco
San Francisco, CA 94107-1739                     hm:  (415) 550-1062

Re: XP smp using a lot of CPU

[Ross Boylan]

On Fri, 2009-05-15 at 11:56 -0300, Marcelo Tosatti wrote:
> Ross,
> 
> Can you confirm the qemu process CPU consumption is down to acceptable
> levels if you dont specify -no-acpi?
> 
> Thanks
Simply starting without -no-acpi did not help.  I tried to do a Windows
XP repair, but seemed to end up nasically doing a reinstall.  The system
now seems to be hung up.

I'm probably going to end up trying a fresh install; I'll report more
results when I have them.
> 
> 
> On Thu, May 14, 2009 at 01:01:11PM -0700, Ross Boylan wrote:
> > On Wed, 2009-05-13 at 09:56 +0300, Avi Kivity wrote:
> > > Ross Boylan wrote:
> > > > I just installed XP into a new VM, specifying -smp 2 for the machine.
> > > > According to top, it's using nearly 200% of a cpu even when I'm not
> > > > doing anything.
> > > >
> > > > Is this real CPU useage, or just a reporting problem (just as my disk
> > > > image is big according to ls, but isn't really)?
> > > >
> > > > If it's real, is there anything I can do about it?
> > > >
> > > > kvm 0.7.2 on Debian Lenny (but 2.6.29 kernel), amd64.  Xeon chips; 32
> > > > bit version of XP pro installed, now fully patched (including the
> > > > Windows Genuine Advantage stuff, though I cancelled it when it wanted to
> > > > run).  
> > > >
> > > > Task manager in XP shows virtually no CPU useage.
> > > >
> > > > Please cc me on responses.
> > > >
> > > >   
> > > 
> > > I'm guessing Windows uses a pio port to sleep, which kvm doesn't 
> > > support.  Can you provide kvm_stat output?
> > markov:~# kvm_stat -1
> > efer_reload                    0         0
> > exits                    9921384       566
> > fpu_reload                267970         0
> > halt_exits                     1         0
> > halt_wakeup                    3         0
> > host_state_reload        4026050        17
> > hypercalls                     0         0
> > insn_emulation           1329455         0
> > insn_emulation_fail          154         0
> > invlpg                    176773         0
> > io_exits                 3818270         0
> > irq_exits                1434046       566
> > irq_injections            326730         0
> > irq_window                164827         0
> > largepages                     0         0
> > mmio_exits                 35892         0
> > mmu_cache_miss             29760         0
> > mmu_flooded                19908         0
> > mmu_pde_zapped             15557         0
> > mmu_pte_updated            82088         0
> > mmu_pte_write              97990         0
> > mmu_recycled                   0         0
> > mmu_shadow_zapped          43276         0
> > mmu_unsync                   891         0
> > mmu_unsync_global              0         0
> > nmi_injections                 0         0
> > nmi_window                     0         0
> > pf_fixed                 1231164         0
> > pf_guest                  276083         0
> > remote_tlb_flush          115606         0
> > request_irq                    0         0
> > request_nmi                    0         0
> > signal_exits                   5         0
> > tlb_flush                 960198         0
> > 
> > This is with the VM displaying the XP "It is now safe to turn off your
> > computer".  CPU remains about 200% from kvm.  Invoked with
> > sudo vdeq kvm -net nic,vlan=1,macaddr=52:54:a0:12:01:00 \
> >     -net vde,vlan=1,sock=/var/run/vde2/tap0.ctl \
> >     -std-vga -hda XP.raw \
> >     -boot c \
> >     -soundhw es1370 -localtime -no-acpi  -m 1G -smp 2
> > 
> > Next I'll trying fiddling with acpi.
> > 
> > -- 
> > Ross Boylan                                      wk:  (415) 514-8146
> > 185 Berry St #5700                               ross@biostat.ucsf.edu
> > Dept of Epidemiology and Biostatistics           fax: (415) 514-8150
> > University of California, San Francisco
> > San Francisco, CA 94107-1739                     hm:  (415) 550-1062
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: XP smp using a lot of CPU [SOLVED]

[Ross Boylan]

Using ACPI fixes the problem; CPU useage is now quite low.  Start line
was
sudo vdeq kvm -net nic,vlan=1,macaddr=52:54:a0:12:01:00 \
    -net vde,vlan=1,sock=/var/run/vde2/tap0.ctl \
    -boot d -cdrom /usr/local/backup/XPProSP3.iso \
    -std-vga -hda /dev/turtle/XP00 \
    -soundhw es1370 -localtime -m 1G -smp 2
I switched to -boot c later.

I ended up doing a fresh install; my repair got mucked up and I got the
message "The requested lookup key was not found in any active activation
context" when I entered a location into MSIE, including when I tried to
run Windows Update.  Googling showed this might indicate some permission
or file corruption issues.  They may have happened during my earlier
(virtual) system hang.

My experience suggests a theory: if you use SMP with XP (i.e., more than
1 virtual processor) you should enable acpi, i.e., not say -no-acpi.  It
this is true, the advice to run windows with -no-acpi should probably be
updated.  It's possible single CPU systems are affected as well.

Ross

Re: XP smp using a lot of CPU [SOLVED]

[Brian Jackson]

On May 15, 2009, at 3:24 PM, Ross Boylan wrote:

> Using ACPI fixes the problem; CPU useage is now quite low.  Start line
> was
> sudo vdeq kvm -net nic,vlan=1,macaddr=52:54:a0:12:01:00 \
>    -net vde,vlan=1,sock=/var/run/vde2/tap0.ctl \
>    -boot d -cdrom /usr/local/backup/XPProSP3.iso \
>    -std-vga -hda /dev/turtle/XP00 \
>    -soundhw es1370 -localtime -m 1G -smp 2
> I switched to -boot c later.
>
> I ended up doing a fresh install; my repair got mucked up and I got  
> the
> message "The requested lookup key was not found in any active  
> activation
> context" when I entered a location into MSIE, including when I tried  
> to
> run Windows Update.  Googling showed this might indicate some  
> permission
> or file corruption issues.  They may have happened during my earlier
> (virtual) system hang.
>
> My experience suggests a theory: if you use SMP with XP (i.e., more  
> than
> 1 virtual processor) you should enable acpi, i.e., not say -no- 
> acpi.  It
> this is true, the advice to run windows with -no-acpi should  
> probably be
> updated.  It's possible single CPU systems are affected as well.


I removed the note about -no-acpi from the howto on the wiki. I don't  
think that's been true for a long time.

--Iggy


>
>
> Ross
>

Re: XP smp using a lot of CPU

[Avi Kivity]

Erik Rull wrote:
> Hi all,
>
> very very interesting.
>
> I have a similar problem but the other way round.
> If my XP runs up tp 100% CPU usage "top" on the linux host reports 
> "only" 33% cpu usage. I would expect around 50% because I only provide 
> one core for the guest. I already increased the process priority of 
> qemu and the io priority, nothing helped. The rest of the CPU is 
> nearly idle, no excessive disk access this time :-)
>
> Any Idea what this could be?

What workload is the guest running?

What is your host cpu type (/proc/cpuinfo)?



-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

Re: XP smp using a lot of CPU

[Erik Rull]

Hi Avi,

here is the cpuinfo - what do you mean with "workload"? The CPU isage is 
around 33%.

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Core(TM)2 CPU         T5600  @ 1.83GHz
stepping        : 2
cpu MHz         : 1833.554
cache size      : 2048 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca 
cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm 
constant_tsc arch_perfmon pebs bts pni monitor ds_cpl vmx est tm2 ssse3 
cx16 xtpr lahf_lm
bogomips        : 3667.98
clflush size    : 64

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Core(TM)2 CPU         T5600  @ 1.83GHz
stepping        : 2
cpu MHz         : 1833.554
cache size      : 2048 KB
physical id     : 0
siblings        : 2
core id         : 1
cpu cores       : 2
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca 
cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm 
constant_tsc arch_perfmon pebs bts pni monitor ds_cpl vmx est tm2 ssse3 
cx16 xtpr lahf_lm
bogomips        : 3666.43
clflush size    : 64

Best regards,

Erik


Avi Kivity wrote:
> Erik Rull wrote:
>> Hi all,
>>
>> very very interesting.
>>
>> I have a similar problem but the other way round.
>> If my XP runs up tp 100% CPU usage "top" on the linux host reports 
>> "only" 33% cpu usage. I would expect around 50% because I only provide 
>> one core for the guest. I already increased the process priority of 
>> qemu and the io priority, nothing helped. The rest of the CPU is 
>> nearly idle, no excessive disk access this time :-)
>>
>> Any Idea what this could be?
> 
> What workload is the guest running?
> 
> What is your host cpu type (/proc/cpuinfo)?
> 
> 
> 

Re: XP smp using a lot of CPU

[Avi Kivity]

Erik Rull wrote:
> Hi Avi,
>
> here is the cpuinfo - what do you mean with "workload"? The CPU isage 
> is around 33%.

What programs is the guest running?

-- 
error compiling committee.c: too many arguments to function

Re: XP smp using a lot of CPU

[Erik Rull]

Hi Avi,

there are some .NET apps running, doing some calculations and graphic 2D 
display, HDD access w/ database and some TCP/IP transfer.

Best regards,

Erik


Avi Kivity wrote:
> Erik Rull wrote:
>> Hi Avi,
>>
>> here is the cpuinfo - what do you mean with "workload"? The CPU isage 
>> is around 33%.
> 
> What programs is the guest running?
> 

Re: XP smp using a lot of CPU

[Avi Kivity]

Erik Rull wrote:
> Hi Avi,
>
> there are some .NET apps running, doing some calculations and graphic 
> 2D display, HDD access w/ database and some TCP/IP transfer.
>

Are you using qcow2?  What is your qemu command line?


-- 
error compiling committee.c: too many arguments to function

Re: XP smp using a lot of CPU

[Erik Rull]

Hi Avi,

no I'm using a partition as a drive, here's my command-line:
taskset 0x00000002 /usr/X11R6/bin/qemu-system-x86_64 -usb -drive 
file=/dev/hda2,cache=off -m 1536 -net nic,macaddr=$MACADDR -net 
tap,script=/etc/qemu-ifup -no-acpi -monitor stdio -L /usr/X11R6/share/qemu 
-usbdevice tablet -boot c -localtime

(I give only one CPU core of the core2duo to the virtualization)
$MACADDR was computed before.

Best regards,

Erik


Avi Kivity wrote:
> Erik Rull wrote:
>> Hi Avi,
>>
>> there are some .NET apps running, doing some calculations and graphic 
>> 2D display, HDD access w/ database and some TCP/IP transfer.
>>
> 
> Are you using qcow2?  What is your qemu command line?
> 
> 

Re: XP smp using a lot of CPU

[Avi Kivity]

Erik Rull wrote:
> Hi Avi,
>
> no I'm using a partition as a drive, here's my command-line:
> taskset 0x00000002 /usr/X11R6/bin/qemu-system-x86_64 -usb -drive 
> file=/dev/hda2,cache=off -m 1536 -net nic,macaddr=$MACADDR -net 
> tap,script=/etc/qemu-ifup -no-acpi -monitor stdio -L 
> /usr/X11R6/share/qemu -usbdevice tablet -boot c -localtime
>
> (I give only one CPU core of the core2duo to the virtualization)
> $MACADDR was computed before.
>

-usbdevice tablet can consume a lot of cpu.  I suggest you try without 
it (and without -usb as well).

-- 
error compiling committee.c: too many arguments to function