Re: [Libevent-users] CPU spinning

[Nick Mathewson <nickm@xxxxxxxxxxxxx>]

On Thu, Sep 6, 2012 at 3:19 PM, Venkatesh Solaiyappan
<sovenkat@xxxxxxxxx> wrote:
> Hello:
>
> In one of our system,  CPU hogs in one of the thread whose stack trace to
> the following:
> Wondering if it is a known issue?? Pls advise.
>
>
>
> #0  0x00007fe60a5ef4c0 in ?? () from /usr/lib64/libevent-2.0.so.5
>
> #1  0x00007fe60a5efa7f in evmap_io_add () from /usr/lib64/libevent-2.0.so.5
>
> #2  0x00007fe60a5e0465 in ?? () from /usr/lib64/libevent-2.0.so.5
>
> #3  0x00007fe60a5e050a in event_add () from /usr/lib64/libevent-2.0.so.5

Hm. That sure shouldn't be happening; that isn't ordinarily an
expensive function.  To be clear, by "CPU Spinning", do you mean that
the thread never leaves that function, and seems to be caught in a
loop?

Can you build with more debug symbols, or do anything to find out
which function it's actually stuck in and what arguments evmap_io_add
was called with?  It could also be good to see the local variables in
these frames.

Does this behavior change if you enable a different backend?  Have you
tried running with libevent's debug_mode enabled to see if it noticies
anything? Did you remember to enable thread support on libevent before
calling other libevent functions?
-- 
Nick
***********************************************************************
To unsubscribe, send an e-mail to majordomo@xxxxxxxxxxxxx with
unsubscribe libevent-users    in the body.