Messages in this thread | | | Date | Thu, 15 Dec 2011 19:19:56 +0400 | From | Andrew Vagin <> | Subject | Re: [PATCH 3/4] trace: add ability to collect call chain of non-current task. |
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On 12/15/2011 12:14 AM, Arun Sharma wrote: > > > On 12/9/11 3:07 AM, Andrey Vagin wrote: > >>> Attached is an alternative approach that does what you allude to above. >> >> * Your method doesn't work for rt scheduler. > > This is no worse than sched_stat_{iowait,sleep} which are also CFS > specific? Sorry. You are right. It's the same. > >> * It doesn't distinguish blocking time and sleeping time. > > Can't we distinguish based on next->state? It will be "Running". We can distinguish based on block_start of sleep_start > >> * This patch does a bit mess between subsystems... > > Which subsystems? sched_switch belongs to scheduler. sched_stat belongs to sched_fair.
I am not sure, that it's bad. Send this patches in LKML.
> >>> perf record -agPe sched:sched_switch --filter "delay > 1000000" -- >>> sleep 1 >> >> Why do you need the option "-a" ? >> > > I'd love to see it work without the -a (so normal users can use it). > > I guess I'll need to move the trace_sched_switch() tracepoint to be > after perf_event_task_sched_in() in finish_task_switch(). > > >>> >>> allows us to collect a lot less. For some reason, "perf script" shows >> >>> the correct delay field, but the sample period still contains 1 (i.e >>> __perf_count() hint is not working for me). >> >> Which kernel do you use? Does it contain "[PATCH] event: don't divide >> events if it has field period"? It works fine with my kernel... >> > > I was using 3.2-rc2. I picked up the patch you reference above. > > # perf report -D | grep SAMPLE.*period: > 3 1437330416084 0x26d908 [0x250]: PERF_RECORD_SAMPLE(IP, 1): > 7276/7806: 0xffffffff8102c0a7 period: 140736819516096 addr: 0 > 3 1437330422290 0x26db58 [0x250]: PERF_RECORD_SAMPLE(IP, 1): > 7276/7806: 0xffffffff8102c0a7 period: 140736819516096 addr: 0 > 3 1437330428485 0x26dda8 [0x250]: PERF_RECORD_SAMPLE(IP, 1): > 7276/7806: 0xffffffff8102c0a7 period: 140736819516096 addr: 0 > > # perf script | grep next_comm=test.*delay | head -3 > test 13070 [023] 1437.320529: sched_switch: > prev_comm=kworker/0:1 prev_pid=0 prev_prio=120 prev_state=R ==> > next_comm=test next_pid=13070 next_prio=120 delay=1096877 > test 13070 [023] 1437.320531: sched_switch: > prev_comm=kworker/0:1 prev_pid=0 prev_prio=120 prev_state=R ==> > next_comm=test next_pid=13070 next_prio=120 delay=1096877 > test 13070 [023] 1437.320532: sched_switch: > prev_comm=kworker/0:1 prev_pid=0 prev_prio=120 prev_state=R ==> > next_comm=test next_pid=13070 next_prio=120 delay=1096877 > > The period still looks bogus i.e. doesn't match delay.
I pushed my tree on github git://github.com/avagin/perf.git. Look at branch "arun" https://github.com/avagin/perf/tree/arun
It works for me. You can find output of commands bellow.
# ./perf record -e sched:sched_switch -agP [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.091 MB perf.data (~3954 samples) ]
# ./perf report -D | grep SAMPLE.*period: 1 1539849049077 0x10d78 [0xc8]: PERF_RECORD_SAMPLE(IP, 1): 34/34: 0xffffffff810527c4 period: 7714488 addr: 0
#./perf script kworker/1:2 34 [001] 1539.849049: sched_switch: prev_comm=perf prev_pid=2700 prev_prio=120 prev_state=R ==> next_comm=kworker/1:2 next_pid=34 next_prio=120 delay=7714488 > Thanks for reviewing. I'll clean up some of these issues and post a > new patch in a couple of days. > > -Arun > > -- > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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