Re: [PATCHSET 0/6] perf sched timehist: Introduce --idle-hist option (v2)

From: David Ahern
Date: Sat Dec 10 2016 - 11:33:34 EST

On 12/8/16 7:47 AM, Namhyung Kim wrote:
> Hi,
> This patchset implements the idle hist feature which analyze reason of system
> idle. Sometimes I need to investigate what makes CPUs to go idle even though
> I have jobs to do. It may be due to I/O, waiting on lock or whatever.


> Namhyung Kim (6):
> perf sched timehist: Split is_idle_sample()
> perf sched timehist: Introduce struct idle_time_data
> perf sched timehist: Save callchain when entering idle
> perf sched timehist: Skip non-idle events when necessary
> perf sched timehist: Add -I/--idle-hist option
> perf sched timehist: Show callchains for idle stat
> tools/perf/Documentation/perf-sched.txt | 4 +
> tools/perf/builtin-sched.c | 252 +++++++++++++++++++++++++++-----
> 2 files changed, 222 insertions(+), 34 deletions(-)


Acked-by: David Ahern <dsahern@xxxxxxxxx>

Suggested improvement: Add the length of the time window. ie., data collected (or analyzed over if --time is used) for N.M seconds. Puts the amount of idle time into perspective.