La mise à l'échelle de la fréquence du processeur de mon ordinateur portable (Intel(R) Core(TM) i7-4810MQ CPU @ 2.80GHz) ne fonctionne pas comme prévu. Après l'installation initiale d'ubuntu 16.04, je n'ai fait aucun changement concernant la gestion de l'énergie ou l'échelle de fréquence du processeur. Normalement, je suis habitué au gouverneur à la demande. Cependant, il semble que ce gouverneur ait été remplacé par un truc de type pstate et le gouverneur powersave dans les noyaux plus récents.
Même sans charge, les fréquences du processeur tournent autour de la gamme 2.x, ce qui rend les ventilateurs bruyants et fait chauffer l'appareil :
$ cat /proc/cpuinfo |grep -i mh
cpu MHz : 3435.468
cpu MHz : 2245.468
cpu MHz : 2800.218
cpu MHz : 2338.765
cpu MHz : 2800.546
cpu MHz : 2801.203
cpu MHz : 2800.875
cpu MHz : 2000.140
$ uptime
14:57:49 up 5:15, 1 user, load average: 0,01, 0,08, 0,16
$ cpufreq-info
cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
driver: intel_pstate
CPUs which run at the same hardware frequency: 0
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 3.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.80 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 2.80 GHz.
analyzing CPU 1:
driver: intel_pstate
CPUs which run at the same hardware frequency: 1
CPUs which need to have their frequency coordinated by software: 1
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 3.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.80 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 2.80 GHz.
analyzing CPU 2:
driver: intel_pstate
CPUs which run at the same hardware frequency: 2
CPUs which need to have their frequency coordinated by software: 2
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 3.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.80 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 2.79 GHz.
analyzing CPU 3:
driver: intel_pstate
CPUs which run at the same hardware frequency: 3
CPUs which need to have their frequency coordinated by software: 3
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 3.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.80 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 2.80 GHz.
analyzing CPU 4:
driver: intel_pstate
CPUs which run at the same hardware frequency: 4
CPUs which need to have their frequency coordinated by software: 4
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 3.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.80 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 2.80 GHz.
analyzing CPU 5:
driver: intel_pstate
CPUs which run at the same hardware frequency: 5
CPUs which need to have their frequency coordinated by software: 5
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 3.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.80 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 2.78 GHz.
analyzing CPU 6:
driver: intel_pstate
CPUs which run at the same hardware frequency: 6
CPUs which need to have their frequency coordinated by software: 6
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 3.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.80 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 2.90 GHz.
analyzing CPU 7:
driver: intel_pstate
CPUs which run at the same hardware frequency: 7
CPUs which need to have their frequency coordinated by software: 7
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 3.80 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 800 MHz and 3.80 GHz.
The governor "powersave" may decide which speed to use
within this range.
current CPU frequency is 2.79 GHz.Curieusement, j'ai également observé le comportement inverse : la machine était sous forte charge mais les fréquences diminuaient jusqu'à ce qu'après environ 20-30 secondes, tous les cœurs atteignent ~ 800 MHz. 20-30sec tous les cœurs ont atteint ~ 800MHz. J'ai vérifié avec cpufreq-info et la configuration semblait correcte (gouverneur powersave, fréquence min/max à des niveaux appropriés). Malheureusement, je suis incapable de reproduire l'erreur...
Avez-vous une idée de la cause de ces problèmes de mise à l'échelle ou de ce qui pourrait être fait pour les résoudre ?
