Messages in this thread Patch in this message | | | Date | Sun, 12 Apr 2009 13:00:39 GMT | From | "Theodore Ts'o" <> | Subject | [tip:tracing/core] tracing: Add documentation for the power tracer |
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Commit-ID: 56c49951747f250d8398582509e02ae5ce1d36d1 Gitweb: http://git.kernel.org/tip/56c49951747f250d8398582509e02ae5ce1d36d1 Author: Theodore Ts'o <tytso@mit.edu> AuthorDate: Sat, 11 Apr 2009 15:51:19 -0400 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Sun, 12 Apr 2009 14:51:42 +0200
tracing: Add documentation for the power tracer
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <1239479479-2603-4-git-send-email-tytso@mit.edu> Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- Documentation/trace/power.txt | 17 +++++++++++++++++ 1 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/Documentation/trace/power.txt b/Documentation/trace/power.txt new file mode 100644 index 0000000..cd805e1 --- /dev/null +++ b/Documentation/trace/power.txt @@ -0,0 +1,17 @@ +The power tracer collects detailed information about C-state and P-state +transitions, instead of just looking at the high-level "average" +information. + +There is a helper script found in scrips/tracing/power.pl in the kernel +sources which can be used to parse this information and create a +Scalable Vector Graphics (SVG) picture from the trace data. + +To use this tracer: + + echo 0 > /sys/kernel/debug/tracing/tracing_enabled + echo power > /sys/kernel/debug/tracing/current_tracer + echo 1 > /sys/kernel/debug/tracing/tracing_enabled + sleep 1 + echo 0 > /sys/kernel/debug/tracing/tracing_enabled + cat /sys/kernel/debug/tracing/trace | \ + perl scripts/tracing/power.pl > out.sv
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