Re: [PATCH] perf tools: session: avoid infinite loop

From: Mark Rutland
Date: Fri Sep 18 2015 - 09:37:33 EST


> > So it looks like I shouldn't have any synthesized events. Have I missed
> > anything?
>
> Yes, you are right. But you are not getting the COMM and MMAP events from
> the exec which means you are killing perf before it execs the workload.

Oh, I see.

> Perf writes through a pipe to its forked child to do the exec, so
> to reproduce it you just need to put everything on the same cpu and play around
> with the sleep number
>
> taskset -c 0 tools/perf/perf record -- sleep 1 & sleep 0.005 ; kill -2 $!
>
> reproduces the problem for me. Of course, since the workload doesn't get exec'ed
> it doesn't matter if it is bogus i.e.
>
> taskset -c 0 tools/perf/perf record -- sdfgsdgdg & sleep 0.005 ; kill -2 $!
>
> also reproduces the problem.

Thanks for confirming!

Mark.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/