strange performance differences of 1.2.2 vs 1.2.5
Sean Chittenden
sean at chittenden.org
Sun Jun 1 23:30:40 UTC 2008
> That's a good guess (Brian? You know about that?:) ... but a bit
> doubtful.
>
> That gettimeofday(2) call that was changed is only made once per
> second
> asyncronously. In order to have such a large performance impact we'd
> be
> looking at some more broad changes.
Hrm.... yeah, it's wrapped in an evtimer_set(3) call. Wait...
libevent(3's gettime() static function will use gettimeofday(2) if
either HAVE_CLOCK_GETTIME and CLOCK_MONOTONIC aren't defined and
use_monotonic is false. Chris, I haven't profiled anything but it may
be worth looking into upgrading libevent(3) since it seems as though
the gettimeofday(2)/gettime() foo was still being toyed with around
the timeframe of libevent 1.3. YMMV as this was only a passing glance
at the problem w/ the details provided. :~) gprof(1) memcached(8) if
you want more specific guidance as to what it could be. -sc
Stack:
libevent(3)
event_base_loop(3)
timeout_correct()
gettime()
--
Sean Chittenden
sean at chittenden.org
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