path: root/Documentation
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authorMike Chan <>2010-05-10 17:54:48 -0700
committerDan Willemsen <>2011-11-30 21:38:19 -0800
commit9075fa48d0b4453038b53a12d2a474312bf68742 (patch)
tree21f99da00bb58be1bbdc3c81757a5396186942ed /Documentation
parent7c89b4e2329d72a84e756028084b722e63103267 (diff)
scheduler: cpuacct: Enable platform hooks to track cpuusage for CPU frequencies
Introduce new platform callback hooks for cpuacct for tracking CPU frequencies Not all platforms / architectures have a set CPU_FREQ_TABLE defined for CPU transition speeds. In order to track time spent in at various CPU frequencies, we enable platform callbacks from cpuacct for this accounting. Architectures that support overclock boosting, or don't have pre-defined frequency tables can implement their own bucketing system that makes sense given their cpufreq scaling abilities. New file: cpuacct.cpufreq reports the CPU time (in nanoseconds) spent at each CPU frequency. Change-Id: I10a80b3162e6fff3a8a2f74dd6bb37e88b12ba96 Signed-off-by: Mike Chan <>
Diffstat (limited to 'Documentation')
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/cgroups/cpuacct.txt b/Documentation/cgroups/cpuacct.txt
index 9d73cc0cadb9..ac8c648ae2bc 100644
--- a/Documentation/cgroups/cpuacct.txt
+++ b/Documentation/cgroups/cpuacct.txt
@@ -39,6 +39,10 @@ system: Time spent by tasks of the cgroup in kernel mode.
user and system are in USER_HZ unit.
+cpuacct.cpufreq file gives CPU time (in nanoseconds) spent at each CPU
+frequency. Platform hooks must be implemented inorder to properly track
+time at each CPU frequency.
cpuacct controller uses percpu_counter interface to collect user and
system times. This has two side effects: