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Message-ID: <000001d10109$10d34630$3279d290$@net> Date: Wed, 7 Oct 2015 07:04:20 -0700 From: "Doug Smythies" <dsmythies@...us.net> To: "'Prarit Bhargava'" <prarit@...hat.com> Cc: "'Kristen Carlson Accardi'" <kristen@...ux.intel.com>, <linux-kernel@...r.kernel.org>, "'Viresh Kumar'" <viresh.kumar@...aro.org>, <linux-pm@...r.kernel.org>, "'Rafael J. Wysocki'" <rjw@...ysocki.net>, "Doug Smythies" <dsmythies@...us.net> Subject: RE: [PATCH] cpufreq, intel_pstate, set max_sysfs_pct and min_sysfs_pct on governor switch On 2015.10.07 03:00 Prarit Bhargava wrote: > On 10/07/2015 02:51 AM, Doug Smythies wrote: >> >> And before patch I get, using primitives and not cpupower: >> Executive Summary: Everything works fine (or at least as I thought it was supposed to). >> >> root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor >> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:powersave >> ... >> /sys/devices/system/cpu/cpu7/cpufreq/scaling_governor:powersave >> root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/intel_pstate/*_perf_* >> /sys/devices/system/cpu/intel_pstate/max_perf_pct:100 >> /sys/devices/system/cpu/intel_pstate/min_perf_pct:42 >> root@s15:/home/doug/temp# echo 50 > /sys/devices/system/cpu/intel_pstate/min_perf_pct >> root@s15:/home/doug/temp# echo 80 > /sys/devices/system/cpu/intel_pstate/max_perf_pct >> root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/intel_pstate/*_perf_* >> /sys/devices/system/cpu/intel_pstate/max_perf_pct:80 >> /sys/devices/system/cpu/intel_pstate/min_perf_pct:50 >> root@s15:/home/doug/temp# for file in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do echo "performance" > $file; done >> root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/intel_pstate/*_perf_* >> /sys/devices/system/cpu/intel_pstate/max_perf_pct:100 >> /sys/devices/system/cpu/intel_pstate/min_perf_pct:100 >> root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor >> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:performance > > The switch has to be from performance to powersave. Switch again and you'll see > the problem. Yes, of course, and I did. The first "powersave" listing was just to show the setup. Continue reading my original reply, also added back below: The "..." stuff is just where I deleted 6 of the 8 CPUs saying the same thing. root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/intel_pstate/*_perf_* /sys/devices/system/cpu/intel_pstate/max_perf_pct:100 /sys/devices/system/cpu/intel_pstate/min_perf_pct:100 root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:performance ... /sys/devices/system/cpu/cpu7/cpufreq/scaling_governor:performance root@s15:/home/doug/temp# for file in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; do echo "powersave" > $file; done root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor:powersave ... /sys/devices/system/cpu/cpu7/cpufreq/scaling_governor:powersave root@s15:/home/doug/temp# grep . /sys/devices/system/cpu/intel_pstate/*_perf_* /sys/devices/system/cpu/intel_pstate/max_perf_pct:80 /sys/devices/system/cpu/intel_pstate/min_perf_pct:50 > I can also reproduce this without using 'cpupower'. Interesting. Then maybe it is a difference between legacy mode and Hardware P state (HWP) mode. I do not have an HWP capable processor to test. I compiled cpupower, but get the same results as I get using primitives, meaning things work properly before the patch and resort to defaults after the patch. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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