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    SubjectRe: [BUG] perf sched broken
    On 01/12/2011 04:11 AM, Arnaldo Carvalho de Melo wrote:
    > 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?
    >

    I will have a look at this now. Thanks for the report.

    - Corey

    > - 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



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