Hi Linus,
Please pull from
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git \
pm-3.15-final
to receive final power management fixes for v3.15 with
top-most commit bf8102228a8bf053051f311e5486042fe0542894
intel_pstate: Improve initial busy calculation
on top of commit fad01e866afdbe01a1f3ec06a39c3a8b9e197014
Linux 3.15-rc8
These are four stable-candidate intel_pstate fixes, including two
fixes for regressions introduced in 3.14.
Specifics:
- Taking non-idle time into account when calculating core busy
time was a mistake and led to a performance regression. Since
the problem it was supposed to address is now taken care of in
a different way, we don't need to do it any more, so drop the
non-idle time tracking from intel_pstate. Dirk Brandewie.
- Changing to fixed point math throughout the busy calculation
introduced rounding errors that adversely affect the accuracy
of intel_pstate's computations. Fix from Dirk Brandewie.
- The PID controller algorithm used by intel_pstate assumes that
the time interval between two adjacent samples will always be the
same which is not the case for deferable timers (used by
intel_pstate) when the system is idle. This leads to inaccurate
predictions and artificially increases convergence times for
the minimum P-state. Fix from Dirk Brandewie.
- intel_pstate carries out computations using 32-bit variables
that may overflow for large enough values of APERF/MPERF. Switch
to using 64-bit variables for computations, from Doug Smythies.
Thanks!
---------------
Dirk Brandewie (3):
intel_pstate: Remove C0 tracking
intel_pstate: Correct rounding in busy calculation
intel_pstate: add sample time scaling
Doug Smythies (1):
intel_pstate: Improve initial busy calculation
---------------
drivers/cpufreq/intel_pstate.c | 52 +++++++++++++++++++++++++-----------------
1 file changed, 31 insertions(+), 21 deletions(-)
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