Re: [BUG] perf sched broken

Arnaldo Carvalho de Melo
2011-01-12T12:11:36Z

Em Wed, Jan 12, 2011 at 10:29:05AM +0100, Stephane Eranian escreveu:
> Hi,
>
> I am trying to use perf sched from tip-x86 but it fails for all my attempts.
>
> First of, I think the event list is stale. This is not so much the
> events themselves
> but rather the flags.
>
> Looks to me like the :r modifier is not supported anymore, so a patch like the
> one below is needed. That helps collect a trace. But then, you can dump
> the trace.

I got to this point as well, and reverting 4c635a4 did the trick for me,
Corey, this is another report for that problem, can you take a look at
it? Stephane, can you try doing a:

git show 4c635a4 | patch -p1 -R

To see if the problem is fixed?

- Arnaldo

> $ perf sched rec dd if=/dev/zero of=/dev/null count=1000000
> 1000000+0 records in
> 1000000+0 records out
> 512000000 bytes (512 MB) copied, 0.589981 s, 868 MB/s
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.481 MB perf.data (~20997 samples) ]
>
> $ perf sched rep
> run measurement overhead: 2934 nsecs
> sleep measurement overhead: 90502 nsecs
> the run test took 999149 nsecs
> the sleep test took 1092248 nsecs
> Fatal: no trace data in the file
>
> $ perf sched trace -D
> usage: perf sched [<options>] {record|latency|map|replay|trace}
>
> -i, --input <file> input file name
> -v, --verbose be more verbose (show symbol address, etc)
> -D, --dump-raw-trace dump raw trace in ASCII
>
> Note that this is not specific to pref sched. If I use perf record directly,
> I run into the same issue:
> $ perf record -R -a -c 1 -e sched:sched_switch -- sleep 1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.365 MB perf.data (~15962 samples) ]
> $./perf report -D
> Fatal: no trace data in the file
>
> Now that perf trace is gone, how to I dump the trace?

Good question, checking this s/trace/script/g fallout.

- Arnaldo