[email protected] [[email protected]] wrote: | From: Kan Liang <[email protected]> | | Add a timer to read counter regularly. Option --counter-read-interval | can be used to set the interval. | Only read counter statistics at the beginning and the end is not enough. | Sometimes, we need fine granularity to do sophisticated analysis. For | example,10-20ms is required to do sophisticated bandwidth analysis. | | Signed-off-by: Kan Liang <[email protected]> | --- | tools/perf/Documentation/perf-record.txt | 8 +++++++ | tools/perf/builtin-record.c | 37 ++++++++++++++++++++++++++++++++ | 2 files changed, 45 insertions(+) | | diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt | index 2e9ce77..c1d9024 100644 | --- a/tools/perf/Documentation/perf-record.txt | +++ b/tools/perf/Documentation/perf-record.txt | @@ -308,6 +308,14 @@ This option sets the time out limit. The default value is 500 ms. | Record context switch events i.e. events of type PERF_RECORD_SWITCH or | PERF_RECORD_SWITCH_CPU_WIDE. | | +--counter-read-interval:: | +Sets the interval to do counter read regularly. This option is only valid
How about "Sets the interval at which the counter should be read"? | +with counter read event (:C). This option is disabled by default. It means | +that the event counter can only be read at the beginning and the end. Should this last sentence be: "When this option is disabled, the event counter can only be read at the beginning and the end?" | +This option could be used when we need fine granularity to do sophisticated | +analysis. For example, 10-20ms is required to do sophisticated memory | +bandwidth analysis. I guess this is independent of the sampling frequency (perf-record -F)? IOW, is the need for --counter-read-interval so we can sample at one frequency, but read the counter values/statistics at a different frequency? Sukadev -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
