Messages in this thread | | | Date | Sun, 05 May 2013 21:22:28 -0600 | From | David Ahern <> | Subject | Re: [PATCH 09/14] perf ftrace: Add 'record' sub-command |
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On 5/5/13 7:57 PM, Namhyung Kim wrote: > Hi David, > > On Fri, 26 Apr 2013 07:44:18 -0600, David Ahern wrote: >> On 4/25/13 12:24 AM, Namhyung Kim wrote: >>> But it looks there's a race between cond_wait() and cond_broatcast(). >>> I'll take a look at that. >> >> Why not use eventfd or a pipe for the signalling instead? > > Thanks for your feedback! > > I didn't have an idea of using eventfd for this case. Does it helpful > to prevent such a deadlock like this?
I have used it to replace pthread_cond_wait / pthread_cond_{signal,broadcast} -- lighter and faster. It was added in 2.6.27 I believe, so will be available for any system that supports perf (record side). For people compiling perf against say RHEL5 (e.g. analysis) you will need a check as to whether it exists.
David
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