diff options
| author | Thomas Gleixner | 2018-03-01 17:33:38 +0100 |
|---|---|---|
| committer | Ingo Molnar | 2018-03-13 07:34:23 +0100 |
| commit | 92af4dcb4e1c5f58dc337bc97bdffd4e853dbc93 (patch) | |
| tree | c3ca7b44890beee561e7bf7d3c44d92a12fa5ce8 /Documentation/trace | |
| parent | 127bfa5f4342e63d83a0b07ece376c2e8878e4a5 (diff) | |
tracing: Unify the "boot" and "mono" tracing clocks
Unify the "boot" and "mono" tracing clocks and document the new behaviour.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Easton <kevin@guarana.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20180301165150.489635255@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/ftrace.txt | 14 |
1 files changed, 3 insertions, 11 deletions
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index d4601df6e72e..bf89f98bfdb9 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -449,17 +449,9 @@ of ftrace. Here is a list of some of the key files: which is montonic but is not subject to any rate adjustments and ticks at the same rate as the hardware clocksource. - boot: This is the boot clock (CLOCK_BOOTTIME) and is based on the - fast monotonic clock, but also accounts for time spent in - suspend. Since the clock access is designed for use in - tracing in the suspend path, some side effects are possible - if clock is accessed after the suspend time is accounted before - the fast mono clock is updated. In this case, the clock update - appears to happen slightly sooner than it normally would have. - Also on 32-bit systems, it's possible that the 64-bit boot offset - sees a partial update. These effects are rare and post - processing should be able to handle them. See comments in the - ktime_get_boot_fast_ns() function for more information. + boot: Same as mono. Used to be a separate clock which accounted + for the time spent in suspend while CLOCK_MONOTONIC did + not. To set a clock, simply echo the clock name into this file. |