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| author | Steven Rostedt <srostedt@redhat.com> | 2011-09-19 11:35:58 -0400 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2011-09-19 11:35:58 -0400 |
| commit | 6249687f76b69cc0b2ad34636f4a18d693ef3262 (patch) | |
| tree | 9c007b85738eb86f113a9a6de1e35129532e5f54 /include/linux/trace_clock.h | |
| parent | c64e148a3be3cb786534ad38298c25c833116c26 (diff) | |
| download | blackbird-op-linux-6249687f76b69cc0b2ad34636f4a18d693ef3262.tar.gz blackbird-op-linux-6249687f76b69cc0b2ad34636f4a18d693ef3262.zip | |
tracing: Add a counter clock for those that do not trust clocks
When debugging tight race conditions, it can be helpful to have a
synchronized tracing method. Although in most cases the global clock
provides this functionality, if timings is not the issue, it is more
comforting to know that the order of events really happened in a precise
order.
Instead of using a clock, add a "counter" that is simply an incrementing
atomic 64bit counter that orders the events as they are perceived to
happen.
The trace_clock_counter() is added from the attempt by Peter Zijlstra
trying to convert the trace_clock_global() to it. I took Peter's counter
code and made trace_clock_counter() instead, and added it to the choice
of clocks. Just echo counter > /debug/tracing/trace_clock to activate
it.
Requested-by: Thomas Gleixner <tglx@linutronix.de>
Requested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/trace_clock.h')
| -rw-r--r-- | include/linux/trace_clock.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/trace_clock.h b/include/linux/trace_clock.h index 7a8130384087..4eb490237d4c 100644 --- a/include/linux/trace_clock.h +++ b/include/linux/trace_clock.h @@ -15,5 +15,6 @@ extern u64 notrace trace_clock_local(void); extern u64 notrace trace_clock(void); extern u64 notrace trace_clock_global(void); +extern u64 notrace trace_clock_counter(void); #endif /* _LINUX_TRACE_CLOCK_H */ |
