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Diffstat (limited to 'Documentation/trace/ftrace.rst')
| -rw-r--r-- | Documentation/trace/ftrace.rst | 22 |
1 files changed, 7 insertions, 15 deletions
diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index 0bc33ad4a3f9..fdf5fb54a04c 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -461,21 +461,13 @@ of ftrace. Here is a list of some of the key files: 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. - - To set a clock, simply echo the clock name into this file:: - - echo global > trace_clock + 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:: + + # echo global > trace_clock trace_marker: |