Re: [PATCH v10 00/25] Speculative page faults

From: Laurent Dufour
Date: Wed May 02 2018 - 10:45:40 EST




On 02/05/2018 16:17, Punit Agrawal wrote:
> Hi Laurent,
>
> One query below -
>
> Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx> writes:
>
> [...]
>
>>
>> Ebizzy:
>> -------
>> The test is counting the number of records per second it can manage, the
>> higher is the best. I run it like this 'ebizzy -mTRp'. To get consistent
>> result I repeated the test 100 times and measure the average result. The
>> number is the record processes per second, the higher is the best.
>>
>> BASE SPF delta
>> 16 CPUs x86 VM 12405.52 91104.52 634.39%
>> 80 CPUs P8 node 37880.01 76201.05 101.16%
>
> How do you measure the number of records processed? Is there a specific
> version of ebizzy that reports this? I couldn't find a way to get this
> information with the ebizzy that's included in ltp.

I'm using the original one : http://ebizzy.sourceforge.net/

>
>>
>> Here are the performance counter read during a run on a 16 CPUs x86 VM:
>> Performance counter stats for './ebizzy -mRTp':
>> 860074 faults
>> 856866 spf
>> 285 pagefault:spf_pte_lock
>> 1506 pagefault:spf_vma_changed
>> 0 pagefault:spf_vma_noanon
>> 73 pagefault:spf_vma_notsup
>> 0 pagefault:spf_vma_access
>> 0 pagefault:spf_pmd_changed
>>
>> And the ones captured during a run on a 80 CPUs Power node:
>> Performance counter stats for './ebizzy -mRTp':
>> 722695 faults
>> 699402 spf
>> 16048 pagefault:spf_pte_lock
>> 6838 pagefault:spf_vma_changed
>> 0 pagefault:spf_vma_noanon
>> 277 pagefault:spf_vma_notsup
>> 0 pagefault:spf_vma_access
>> 0 pagefault:spf_pmd_changed
>>
>> In ebizzy's case most of the page fault were handled in a speculative way,
>> leading the ebizzy performance boost.
>
> A trial run showed increased fault handling when SPF is enabled on an
> 8-core ARM64 system running 4.17-rc3. I am using a port of your x86
> patch to enable spf on arm64.
>
> SPF
> ---
>
> Performance counter stats for './ebizzy -vvvmTRp':
>
> 1,322,736 faults
> 1,299,241 software/config=11/
>
> 10.005348034 seconds time elapsed
>
> No SPF
> -----
>
> Performance counter stats for './ebizzy -vvvmTRp':
>
> 708,916 faults
> 0 software/config=11/
>
> 10.005807432 seconds time elapsed

Thanks for sharing these good numbers !

> Thanks,
> Punit
>
> [...]
>