Re: process 'stuck' at exit.

[Dave Jones]

On Tue, Dec 10, 2013 at 01:18:20PM -0800, Linus Torvalds wrote:
 > On Tue, Dec 10, 2013 at 1:06 PM, Darren Hart <dvhart@xxxxxxxxxxxxxxx> wrote:
 > >
 > >    . Knowing exactly what syscall was made would
 > > be very useful, but I don't know if that information is even available
 > > anymore.
 > 
 > Well, the loop should be visible in the profile, since it's still active.
 > 
 > So doing something like
 > 
 >      perf record -e cycles:pp -g -a sleep 60
 > 
 > to get a good profile for a minute, and then looking at the
 > instruction-level profiles in futex_requeue() should be possible.
 > 
 > Of course, inlining etc often makes those rather hard to see, and the
 > bulk of the profile is clearly all about the lock debugging overhead,
 > but if the loop is in futex_requeue() then that *should* be visible in
 > the profile, even if it may not be anywhere near the top..
 > 
 > Dave?

http://www.codemonkey.org.uk/junk/perf.data.xz

	Dave

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