On 23/02/16 01:46, Shannon Zhao wrote:
>
>
> On 2016/2/23 1:51, Marc Zyngier wrote:
>> On 22/02/16 09:37, Shannon Zhao wrote:
>>> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>>>
>>> We are about to trap and emulate accesses to each PMU register
>>> individually. This adds the context offsets for the AArch64 PMU
>>> registers.
>>>
>>> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>>> Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>
>>> Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
>>> ---
>>> arch/arm64/include/asm/kvm_host.h | 15 +++++++++++++++
>>> 1 file changed, 15 insertions(+)
>>>
>>> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
>>> index 6f0241f..6bab7fb 100644
>>> --- a/arch/arm64/include/asm/kvm_host.h
>>> +++ b/arch/arm64/include/asm/kvm_host.h
>>> @@ -115,6 +115,21 @@ enum vcpu_sysreg {
>>> MDSCR_EL1, /* Monitor Debug System Control Register */
>>> MDCCINT_EL1, /* Monitor Debug Comms Channel Interrupt Enable Reg */
>>>
>>> + /* Performance Monitors Registers */
>>> + PMCR_EL0, /* Control Register */
>>> + PMOVSSET_EL0, /* Overflow Flag Status Set Register */
>>> + PMSELR_EL0, /* Event Counter Selection Register */
>>> + PMEVCNTR0_EL0, /* Event Counter Register (0-30) */
>>> + PMEVCNTR30_EL0 = PMEVCNTR0_EL0 + 30,
>>> + PMCCNTR_EL0, /* Cycle Counter Register */
>>> + PMEVTYPER0_EL0, /* Event Type Register (0-30) */
>>> + PMEVTYPER30_EL0 = PMEVTYPER0_EL0 + 30,
>>> + PMCCFILTR_EL0, /* Cycle Count Filter Register */
>>> + PMCNTENSET_EL0, /* Count Enable Set Register */
>>> + PMINTENSET_EL1, /* Interrupt Enable Set Register */
>>> + PMUSERENR_EL0, /* User Enable Register */
>>> + PMSWINC_EL0, /* Software Increment Register */
>>> +
>>
>> I've just noticed a rather fundamental issue with this: this makes it
>> impossible to bisect the whole series.
>>
> Ah, sorry. Will fix this.
Thanks.
>
>> I was trying to pinpoint a performance regression with this series, and
>> started bisecting.
> You mean this series introduce a performance regression? Is there any
> method to measure that? Then I can have a look too.
I'm not quite sure this is related to this series. What I'm observing is
that hackbench runs faster in a VM spawned with kvmtool than the same VM
run with qemu. As in significantly faster (62 vs 55 seconds - 2 vcpus,
1GB memory).
Given that hackbench doesn't do any IO, I don't really see why we should
see a difference. I'll add support for the PMU to kvmtool today, and
I'll be able to see if that has any impact.
M.
--
Jazz is not dead. It just smells funny...
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