Re: [RFC PATCH] crypto: crc32c-pclmul - Use pmovzxdq to shrink K_table

From: Dirk Brandewie
Date: Fri May 30 2014 - 14:45:27 EST

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On 05/30/2014 10:56 AM, Tim Chen wrote:
> On Thu, 2014-05-29 at 21:16 -0400, Dave Jones wrote:
>> On Thu, May 29, 2014 at 06:07:16PM -0700, Tim Chen wrote:
>> > On Thu, 2014-05-29 at 19:54 -0400, George Spelvin wrote:
>> > > Sorry for the delay; my Ivy Bridge test machine isn't in my
>> > > office and getting to the console to tweak the BIOS is a
>> > > bit of a bother.
>> > >
>> > > Anyway, i7-4930K, turbo boost & hyperthreading disabled,
>> > > $ cat /sys/devices/system/cpu/cpu?/cpufreq/scaling_governor
>> > > performance
>> > > performance
>> > > performance
>> > > performance
>> > > performance
>> > > performance
>> > >
>> > > Oddly, though, CPU speed still seems to be fluctuating:
>> > > $ grep MHz /proc/cpuinfo
>> > > cpu MHz : 1255.875
>> > > cpu MHz : 3168.375
>> > > cpu MHz : 3062.125
>> > > cpu MHz : 1468.375
>> > > cpu MHz : 1309.000
>> > > cpu MHz : 2212.125
>> > > $ grep MHz /proc/cpuinfo
>> > > cpu MHz : 1255.875
>> > > cpu MHz : 2690.250
>> > > cpu MHz : 1255.875
>> > > cpu MHz : 2530.875
>> > > cpu MHz : 2212.125
>> > > cpu MHz : 1521.500
>> >
>> > This is odd. On my Ivy Bridge system the CPU speed from /proc/cpuinfo
>> > is at max freq once I set the performance governor.
>> > The numbers above almost look like
>> > the cpu frequency is fluctuating and an average is taken.
>> > What version of the kernel are you running? Is
>> > CONFIG_CPU_FREQ_GOV_PERFORMANCE compiled in?
>> >
>> > Does /sys/devices/system/cpu/cpu?/cpufreq/scaling_cur_freq
>> > also changes?
>> >
>> > Can you check what are the available governors in your system
>> > and available frequencies?
>> >
>> > cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
>> > cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
>> >
>> > If userspace governor is available, you can try set the governor
>> > to userspace, then pin frequency to 3400 MHz (assuming that's your
>> > max) with command like:
>>
>> intel_pstate overrides any governor choice you make through sysfs.
>>
>> Dave
>>
>
> Dirk,
>
> Wonder if this the right behavior for intel_pstate that when I set the
> governor to performance, intel_pstate driver still adjusts
> the cpu frequencies around?

No, the value returned is a measured/delivered frequency instead of the P state
requested which is what the other governors return.

>
> Turbotstat also confirms that the frequencies are not at max,
> even though the max_perf_pct and min_perf_pct are both set at 100.
>

I calculate frequency the same way turbostat does but my samples are a *lot*
shorter.

> I ran on my HSW system with 3.15-rc7 kernel and see similar
> issue that Geroge reported.
>
> It is really a pain when we need to do performance benchmarking and
> need to have a constant cpu frequency.
>

With turbostat from rc7.
[root@echolake turbostat]# ./turbostat
Core CPU Avg_MHz %Busy Bzy_MHz TSC_MHz SMI CPU%c1 CPU%c3 CPU%c6 CPU%c7 CoreTmp PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 PkgWatt CorWatt GFXWatt
- - 1 0.08 1178 3492 0 0.12 0.08 0.01 99.71 29 29 99.23 0.00 0.00 0.00 2.18 0.00 0.00
0 0 2 0.19 1189 3492 0 0.22 0.30 0.00 99.29 29 29 99.24 0.00 0.00 0.00 2.18 0.00 0.00
0 4 1 0.12 1253 3492 0 0.29
1 1 0 0.03 1065 3492 0 0.03 0.00 0.00 99.93 23
1 5 0 0.01 1104 3492 0 0.05
2 2 0 0.02 1275 3492 0 0.22 0.00 0.03 99.73 24
2 6 2 0.18 1220 3492 0 0.06
3 3 0 0.01 992 3492 0 0.07 0.00 0.01 99.90 23
3 7 0 0.05 915 3492 0 0.04
Core CPU Avg_MHz %Busy Bzy_MHz TSC_MHz SMI CPU%c1 CPU%c3 CPU%c6 CPU%c7 CoreTmp PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 PkgWatt CorWatt GFXWatt
- - 1 0.06 1034 3492 0 0.09 5.15 0.00 94.70 28 28 99.49 0.00 0.00 0.00 2.48 0.01 0.00
0 0 1 0.09 1066 3492 0 0.17 0.01 0.00 99.73 28 28 99.49 0.00 0.00 0.00 2.48 0.01 0.00
0 4 1 0.12 1036 3492 0 0.14
1 1 0 0.04 1009 3492 0 0.05 20.59 0.00 79.32 24
1 5 0 0.02 922 3492 0 0.07
2 2 0 0.03 924 3492 0 0.15 0.00 0.00 99.82 25
2 6 1 0.12 1117 3492 0 0.06
3 3 0 0.01 911 3492 0 0.04 0.01 0.00 99.94 22
3 7 0 0.03 856 3492 0 0.02
Core CPU Avg_MHz %Busy Bzy_MHz TSC_MHz SMI CPU%c1 CPU%c3 CPU%c6 CPU%c7 CoreTmp PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 PkgWatt CorWatt GFXWatt
- - 1 0.08 889 3492 0 0.12 0.03 0.06 99.71 29 29 99.32 0.00 0.00 0.00 2.21 0.00 0.00
0 0 1 0.11 867 3492 0 0.20 0.02 0.22 99.44 29 29 99.32 0.00 0.00 0.00 2.21 0.00 0.00
0 4 1 0.14 907 3492 0 0.17
1 1 1 0.12 809 3492 0 0.04 0.11 0.01 99.73 24
1 5 0 0.01 798 3492 0 0.14
2 2 0 0.03 863 3492 0 0.18 0.00 0.01 99.78 24
2 6 1 0.14 1013 3492 0 0.07
3 3 0 0.02 853 3492 0 0.09 0.00 0.00 99.89 23
3 7 1 0.06 815 3492 0 0.05
^C
[root@echolake turbostat]# echo 100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct
[root@echolake turbostat]# ./turbostat
Core CPU Avg_MHz %Busy Bzy_MHz TSC_MHz SMI CPU%c1 CPU%c3 CPU%c6 CPU%c7 CoreTmp PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 PkgWatt CorWatt GFXWatt
- - 1 0.03 3489 3492 0 2.43 0.01 0.00 97.53 30 30 90.20 0.00 0.00 0.00 2.85 0.06 0.00
0 0 1 0.04 3470 3492 0 0.09 0.00 0.00 99.88 30 30 90.20 0.00 0.00 0.00 2.85 0.06 0.00
0 4 2 0.06 3492 3492 0 0.07
1 1 1 0.02 3495 3492 0 0.05 0.03 0.00 99.90 25
1 5 0 0.00 3494 3492 0 0.07
2 2 0 0.01 3492 3492 0 9.53 0.00 0.01 90.45 25
2 6 1 0.04 3492 3492 0 9.50
3 3 1 0.03 3492 3492 0 0.05 0.01 0.00 99.91 23
3 7 1 0.02 3493 3492 0 0.06
Core CPU Avg_MHz %Busy Bzy_MHz TSC_MHz SMI CPU%c1 CPU%c3 CPU%c6 CPU%c7 CoreTmp PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 PkgWatt CorWatt GFXWatt
- - 1 0.02 3492 3492 0 4.93 0.00 0.00 95.04 30 30 80.19 0.00 0.00 0.00 3.54 0.10 0.00
0 0 1 0.02 3491 3492 0 0.08 0.01 0.00 99.89 30 30 80.19 0.00 0.00 0.00 3.54 0.10 0.00
0 4 2 0.05 3492 3492 0 0.05
1 1 0 0.01 3492 3492 0 0.02 0.00 0.00 99.97 24
1 5 0 0.01 3493 3492 0 0.02
2 2 0 0.01 3493 3492 0 19.65 0.01 0.00 80.34 24
2 6 2 0.05 3493 3492 0 19.61
3 3 1 0.01 3492 3492 0 0.02 0.00 0.00 99.97 23
3 7 0 0.01 3494 3492 0 0.02
Core CPU Avg_MHz %Busy Bzy_MHz TSC_MHz SMI CPU%c1 CPU%c3 CPU%c6 CPU%c7 CoreTmp PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 PkgWatt CorWatt GFXWatt
- - 2 0.05 3493 3492 0 1.64 0.01 0.00 98.29 30 30 93.25 0.00 0.00 0.00 2.64 0.04 0.00
0 0 4 0.12 3492 3492 0 0.13 0.01 0.00 99.74 30 30 93.25 0.00 0.00 0.00 2.64 0.04 0.00
0 4 2 0.06 3493 3492 0 0.19
1 1 1 0.02 3492 3492 0 0.03 0.04 0.00 99.91 23
1 5 0 0.01 3494 3492 0 0.04
2 2 0 0.01 3492 3492 0 6.42 0.00 0.00 93.57 25
2 6 6 0.16 3492 3492 0 6.27
3 3 0 0.01 3501 3492 0 0.05 0.01 0.00 99.93 22
3 7 1 0.03 3492 3492 0 0.03
[root@echolake turbostat]# grep MH /proc/cpuinfo
cpu MHz : 997.089
cpu MHz : 797.480
cpu MHz : 998.320
cpu MHz : 800.078
cpu MHz : 845.878
cpu MHz : 801.445
cpu MHz : 800.078
cpu MHz : 800.351
[root@echolake turbostat]# echo 100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct
[root@echolake turbostat]# grep MH /proc/cpuinfo
cpu MHz : 3497.128
cpu MHz : 3506.699
cpu MHz : 3500.273
cpu MHz : 3500.273
cpu MHz : 3500.000
cpu MHz : 3500.000
cpu MHz : 3500.000
cpu MHz : 3495.898

> Thanks.
>
> Tim
>

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Next message: Arnd Bergmann: "Re: [PATCH v2] devicetree: Add generic IOMMU device tree bindings"
Previous message: Dan Carpenter: "Re: [PATCH] staging/goldfish: Clean up trailing whitespace."
In reply to: Tim Chen: "Re: [RFC PATCH] crypto: crc32c-pclmul - Use pmovzxdq to shrink K_table"
Next in thread: Tim Chen: "Re: [RFC PATCH] crypto: crc32c-pclmul - Use pmovzxdq to shrink K_table"
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