* Guest virtual CPUs limited to only 50% of host CPU
@ 2011-03-31 21:03 Drew Johnson
2011-04-05 9:03 ` Avi Kivity
0 siblings, 1 reply; 3+ messages in thread
From: Drew Johnson @ 2011-03-31 21:03 UTC (permalink / raw)
To: kvm
Hi,
I am using Qemu-KVM-0.12.5 on Intel Xeon (Vt-x enabled) processors and
monitoring the system using htop on the host. On the processors that
are running Qemu-KVM I am seeing a 50/50 split between userspace and
guest ("gu:" in htop). I have pinned the vCPU qemu-kvm threads to
specific host CPUs using taskset. In the guest the CPUs are nearly
100% userspace in htop.
Does anyone have ideas on why this is? Is there a way I can get much
higher utilization for the guest virtual CPUs wrt the host?
Thanks in advance!
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Guest virtual CPUs limited to only 50% of host CPU
2011-03-31 21:03 Guest virtual CPUs limited to only 50% of host CPU Drew Johnson
@ 2011-04-05 9:03 ` Avi Kivity
2011-04-29 0:30 ` Drew Johnson
0 siblings, 1 reply; 3+ messages in thread
From: Avi Kivity @ 2011-04-05 9:03 UTC (permalink / raw)
To: Drew Johnson; +Cc: kvm
On 03/31/2011 11:03 PM, Drew Johnson wrote:
> Hi,
>
> I am using Qemu-KVM-0.12.5
This is somewhat old. Try upgrading.
> on Intel Xeon (Vt-x enabled) processors and
> monitoring the system using htop on the host. On the processors that
> are running Qemu-KVM I am seeing a 50/50 split between userspace and
> guest ("gu:" in htop). I have pinned the vCPU qemu-kvm threads to
> specific host CPUs using taskset. In the guest the CPUs are nearly
> 100% userspace in htop.
>
> Does anyone have ideas on why this is? Is there a way I can get much
> higher utilization for the guest virtual CPUs wrt the host?
>
Please build qemu with --disable-cpu-strip and run 'perf top' to see
what's going on.
--
error compiling committee.c: too many arguments to function
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Guest virtual CPUs limited to only 50% of host CPU
2011-04-05 9:03 ` Avi Kivity
@ 2011-04-29 0:30 ` Drew Johnson
0 siblings, 0 replies; 3+ messages in thread
From: Drew Johnson @ 2011-04-29 0:30 UTC (permalink / raw)
To: Avi Kivity; +Cc: kvm
Thanks for the reply. Turns out it was htop reporting it wrong. The
utime in /proc/stat already includes guest time.
On Tue, Apr 5, 2011 at 2:03 AM, Avi Kivity <avi@redhat.com> wrote:
> On 03/31/2011 11:03 PM, Drew Johnson wrote:
>>
>> Hi,
>>
>> I am using Qemu-KVM-0.12.5
>
> This is somewhat old. Try upgrading.
>
>> on Intel Xeon (Vt-x enabled) processors and
>> monitoring the system using htop on the host. On the processors that
>> are running Qemu-KVM I am seeing a 50/50 split between userspace and
>> guest ("gu:" in htop). I have pinned the vCPU qemu-kvm threads to
>> specific host CPUs using taskset. In the guest the CPUs are nearly
>> 100% userspace in htop.
>>
>> Does anyone have ideas on why this is? Is there a way I can get much
>> higher utilization for the guest virtual CPUs wrt the host?
>>
>
> Please build qemu with --disable-cpu-strip and run 'perf top' to see what's
> going on.
>
> --
> error compiling committee.c: too many arguments to function
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-04-29 0:30 UTC | newest]
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2011-03-31 21:03 Guest virtual CPUs limited to only 50% of host CPU Drew Johnson
2011-04-05 9:03 ` Avi Kivity
2011-04-29 0:30 ` Drew Johnson
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