Re: [cpufreq] 06c4d00466: will-it-scale.per_process_ops -53.4% regression

kernel test robot
2020-03-26T08:34:27Z

On Wed, Mar 25, 2020 at 11:32:06AM +0100, Thomas Gleixner wrote:
> Rong Chen <rong.a.chen@intel.com> writes:
> > On 3/24/20 6:24 PM, Andy Shevchenko wrote:
> >> On Tue, Mar 24, 2020 at 8:02 AM kernel test robot <rong.a.chen@intel.com> wrote:
> >>> Greeting,
> >>>
> >>> FYI, we noticed a -53.4% regression of will-it-scale.per_process_ops due to commit:
> >>> commit: 06c4d00466eb374841bc84c39af19b3161ff6917 ("[patch 09/22] cpufreq: Convert to new X86 CPU match macros")
> >>> url: https://github.com/0day-ci/linux/commits/Thomas-Gleixner/x86-devicetable-Move-x86-specific-macro-out-of-generic-code/20200321-031729
> >>> base: https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git linux-next
> >>>
> >>> in testcase: will-it-scale
> >>> on test machine: 4 threads Intel(R) Core(TM) i3-3220 CPU @ 3.30GHz with 8G memory
> >>> with following parameters:
> >>
> >> drivers/cpufreq/speedstep-centrino.c change missed the terminator,
> >> perhaps it's a culprit, because I don't believe removing dups and
> >> reordering lines may affect this.
> >> Can you restore terminator there and re-test?
> >>
> >
> > I have retested with the change, but it has no effect on the performance.
>
> Bah. The binary equivalence testing detected this, but I obvioulsy
> missed it. Delta fix below.
>
> Thanks,
>
> tglx
>
> 8<--------------
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -2727,7 +2727,7 @@ static inline void intel_pstate_request_
>
> #define X86_MATCH_HWP(model, hwp_mode) \
> X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6, INTEL_FAM6_##model, \
> - X86_FEATURE_APERFMPERF, hwp_mode)
> + X86_FEATURE_HWP, hwp_mode)
>
> static const struct x86_cpu_id hwp_support_ids[] __initconst = {
> X86_MATCH_HWP(BROADWELL_X, INTEL_PSTATE_HWP_BROADWELL),

Hi Thomas,

The patch can fix the regression:

commit:
06c4d00466 ("cpufreq: Convert to new X86 CPU match macros")
d369f9be1a ("the fix patch")

06c4d00466eb3748 d369f9be1ad1e22da4e8f03557 testcase/testparams/testbox
---------------- -------------------------- ---------------------------
%stddev change %stddev
\ | \
93200 114% 199599 will-it-scale/performance-process-16-read2-ucode=0x21/lkp-ivb-d02
93200 114% 199599 GEO-MEAN will-it-scale.per_process_ops

Best Regards,
Rong Chen