Re: [RFC PATCH 4/4] perf: add timehist command

From: David Ahern
Date: Thu Jun 20 2013 - 11:00:19 EST


On 6/20/13 4:46 AM, Ingo Molnar wrote:
Looks very useful!

This is the kind of analysis I thought 'perf sched' might one day end up
doing.

Do you plan to submit it non-RFC, to be merged?

Yes. Hopefully I can find time to work on it over the next 2 months for 3.12, 3.13 at the latest.


Your tool could take over the somewhat stale 'perf sched' command as well
btw., while possibly carrying over some of the perf sched features like
'replay'.

'perf sched record' enough events to support the ones you need:

> perf record -e cs -c 1 -ag -- <workload>
plus:

'perf sched sum[mary]' # show the summary
'perf sched tree' # could show the tree.
'perf sched hist[ogram]' # would show the histogram

i.e. feel free to take over 'perf sched' to suit your 'timehist' workflow
and logic. As the main (and somewhat overworked) author of 'perf sched' I
have no problem with you taking it over, at all.

It should be part of perf-sched. It is not at the moment for a number of (mostly shortcut) reasons. For the next iteration I will look at combining it with perf-sched and in the process I will go through the existing code for perf-sched.

As an FYI I also have a daemon that provides the functionality in a flight recorder mode but with data dumped only when requested. Future project to integrate that with perf. ;-)


You could also add a 'perf timehist' alias to the new 'perf sched'
command, to keep your original (and well established?) naming.

It is well established internally, so a convenience shortcut would lessen the pain of moving to newer perf versions when the time comes.

David
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