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| author | Dirk Brandewie <dirk.j.brandewie@intel.com> | 2014-05-29 09:32:24 -0700 |
|---|---|---|
| committer | Show Liu <show.liu@linaro.org> | 2014-06-18 12:05:30 +0800 |
| commit | 72f0c934039695a91bc0b1d2c57c001aae39911b (patch) | |
| tree | 4862784d0202325e1a87f58ccafa818460f105b4 /fs | |
| parent | 9b115000e7deeb3ce53e48b3ca4844904063cfa1 (diff) | |
intel_pstate: add sample time scaling
commit c4ee841f602e5eef8eab673295c49c5b49d7732b upstream.
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.
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
0 files changed, 0 insertions, 0 deletions