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authorLinus Torvalds <torvalds@linux-foundation.org>2009-06-10 22:53:40 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-10 22:53:40 -0400
commit862366118026a358882eefc70238dbcc3db37aac (patch)
tree4eb62bc10327a5afac064a95a091ea05ecd2acc1 /Documentation/trace/power.txt
parent57eee9ae7bbcfb692dc96c739a5184adb6349733 (diff)
parent511b01bdf64ad8a38414096eab283c7784aebfc4 (diff)
Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (244 commits) Revert "x86, bts: reenable ptrace branch trace support" tracing: do not translate event helper macros in print format ftrace/documentation: fix typo in function grapher name tracing/events: convert block trace points to TRACE_EVENT(), fix !CONFIG_BLOCK tracing: add protection around module events unload tracing: add trace_seq_vprint interface tracing: fix the block trace points print size tracing/events: convert block trace points to TRACE_EVENT() ring-buffer: fix ret in rb_add_time_stamp ring-buffer: pass in lockdep class key for reader_lock tracing: add annotation to what type of stack trace is recorded tracing: fix multiple use of __print_flags and __print_symbolic tracing/events: fix output format of user stack tracing/events: fix output format of kernel stack tracing/trace_stack: fix the number of entries in the header ring-buffer: discard timestamps that are at the start of the buffer ring-buffer: try to discard unneeded timestamps ring-buffer: fix bug in ring_buffer_discard_commit ftrace: do not profile functions when disabled tracing: make trace pipe recognize latency format flag ...
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1The power tracer collects detailed information about C-state and P-state
2transitions, instead of just looking at the high-level "average"
3information.
4
5There is a helper script found in scrips/tracing/power.pl in the kernel
6sources which can be used to parse this information and create a
7Scalable Vector Graphics (SVG) picture from the trace data.
8
9To use this tracer:
10
11 echo 0 > /sys/kernel/debug/tracing/tracing_enabled
12 echo power > /sys/kernel/debug/tracing/current_tracer
13 echo 1 > /sys/kernel/debug/tracing/tracing_enabled
14 sleep 1
15 echo 0 > /sys/kernel/debug/tracing/tracing_enabled
16 cat /sys/kernel/debug/tracing/trace | \
17 perl scripts/tracing/power.pl > out.sv