tree c704a0f9e3f700f0b789b29c11646de90a565aff
parent b2a33c172890b231444803b0bb38c25ac5a0f274
author David C Niemi <dniemi@verisign.com> 1286398464 -0400
committer Dave Jones <davej@redhat.com> 1287762287 -0400

[CPUFREQ] add sampling_down_factor tunable to improve ondemand performance

Adds a new global tunable, sampling_down_factor.  Set to 1 it makes no
changes from existing behavior, but set to greater than 1 (e.g. 100)
it acts as a multiplier for the scheduling interval for reevaluating
load when the CPU is at its top speed due to high load.  This improves
performance by reducing the overhead of load evaluation and helping
the CPU stay at its top speed when truly busy, rather than shifting
back and forth in speed.  This tunable has no effect on behavior at
lower speeds/lower CPU loads.

This patch is against 2.6.36-rc6.

This patch should help solve kernel bug 19672 "ondemand is slow".

Signed-off-by: David Niemi <dniemi@verisign.com>
Acked-by: Venkatesh Pallipadi <venki@google.com>
CC: Daniel Hollocher <danielhollocher@gmail.com>
CC: <cpufreq-list@vger.kernel.org>
CC: <linux-kernel@vger.kernel.org>
Signed-off-by: Dave Jones <davej@redhat.com>