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authorVishwanath BS <vishwanath.bs@ti.com>2011-01-25 20:12:00 -0500
committerNicolas Pitre <nicolas.pitre@linaro.org>2011-02-08 13:30:07 -0500
commitd983450dfa62e678c512fcda29e7757c59edc428 (patch)
parent6ca27f9c10b70f43d7c3cdaffb220846d36be21b (diff)
cpufreq: Add documentation for sampling_down_factorlinaro-linux-2.6.37-upstream-08Feb2011
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>
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