| Re: [PATCH 0/7] Profiling sleep times (v3) [message #44612 is a reply to message #44405] |
Wed, 07 December 2011 20:33  |
Arun Sharma
Messages: 2
Registered: December 2011
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Junior Member |
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On 12/5/11 11:15 PM, Andrey Vagin wrote:
> Arun Sharma said, that the second versions of patches works ok for him.
> (Arun is the first user of this functionality after me.)
Yes - Andrey's patches (v2) have been functional for me when used via:
perf record -agP -e sched:sched_switch --filter "prev_state == 1 ||
prev_state == 2" -e sched:sched_stat_sleep,sched:sched_stat_iowait --
sleep 3
mv perf.data{,.old}; perf inject -s -i perf.data.old -o perf.data
perf report --stdio -g graph --sort pid -C command-name
There are two major issues though:
* The above command lines cause us to collect way too much data and perf
can't keep up on a busy server
Eg:
Warning:
Processed 55182 events and lost 13 chunks!
Check IO/CPU overload!
* Requires root access
I suspect there is a way to stash the delay information available at
enqueue_sleeper() into the task_struct (or some place else) and make it
available at the sched:sched_switch tracepoint. This would solve both of
the problems above, but I don't have a patch yet.
-Arun
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