https://github.com/torvalds/linux
Revision c4ee841f602e5eef8eab673295c49c5b49d7732b authored by Dirk Brandewie on 29 May 2014, 16:32:24 UTC, committed by Rafael J. Wysocki on 02 June 2014, 10:45:05 UTC
The PID assumes that samples are of equal time, which for a deferable
timers this is not true when the system goes idle.  This causes the
PID to take a long time to converge to the min P state and depending
on the pattern of the idle load can make the P state appear stuck.

The hold-off value of three sample times before using the scaling is
to give a grace period for applications that have high performance
requirements and spend a lot of time idle,  The poster child for this
behavior is the ffmpeg benchmark in the Phoronix test suite.

Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
1 parent f0fe3cd
History
Tip revision: c4ee841f602e5eef8eab673295c49c5b49d7732b authored by Dirk Brandewie on 29 May 2014, 16:32:24 UTC
intel_pstate: add sample time scaling
Tip revision: c4ee841
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usr
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.gitignore -rw-r--r-- 1.1 KB
.mailmap -rw-r--r-- 4.4 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 93.6 KB
Kbuild -rw-r--r-- 2.5 KB
Kconfig -rw-r--r-- 252 bytes
MAINTAINERS -rw-r--r-- 272.1 KB
Makefile -rw-r--r-- 50.5 KB
README -rw-r--r-- 18.3 KB
REPORTING-BUGS -rw-r--r-- 7.3 KB

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