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authorVishwanath BS <vishwanath.bs@ti.com>2011-01-25 20:12:00 -0500
committerNicolas Pitre <nicolas.pitre@linaro.org>2011-02-21 23:10:33 -0500
commit80c25683e753b73d09f189de91072486b59ae281 (patch)
tree8e2131239ac081e5b072211d885dab5d504f34f8
parente4907eff28231e3b437c981957c7175617ba73a4 (diff)
downloadlinux-linaro-80c25683e753b73d09f189de91072486b59ae281.tar.gz
cpufreq: Add documentation for sampling_down_factor
Update cpufreq governor documentation for sampling_down_factor tunable parameter. Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com> Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
-rw-r--r--Documentation/cpu-freq/governors.txt11
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/cpu-freq/governors.txt b/Documentation/cpu-freq/governors.txt
index 737988fca64..e74d0a2eb1c 100644
--- a/Documentation/cpu-freq/governors.txt
+++ b/Documentation/cpu-freq/governors.txt
@@ -158,6 +158,17 @@ intensive calculation on your laptop that you do not care how long it
takes to complete as you can 'nice' it and prevent it from taking part
in the deciding process of whether to increase your CPU frequency.
+sampling_down_factor: this parameter controls the rate at which the
+kernel makes a decision on when to decrease the frequency while running
+at top speed. When set to 1 (the default) decisions to reevaluate load
+are made at the same interval regardless of current clock speed. But
+when 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.
+
2.5 Conservative
----------------