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Commit 56c49951 authored by Theodore Ts'o's avatar Theodore Ts'o Committed by Ingo Molnar
Browse files

tracing: Add documentation for the power tracer 



Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Acked-by: default avatarArjan 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: default avatarIngo Molnar <mingo@elte.hu>
parent 5cb3d1d9

Documentation/trace/power.txt

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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