strange performance differences of 1.2.2 vs 1.2.5

Brian Aker brian at
Mon Jun 2 01:31:55 UTC 2008


BTW back when we were looking at this change this was the blog post I  

While I suspect that the gettimeofday() is an issue for FreeBSD if its  
call is that much slower then Linux, I am having some doubts about  
this being the reason behind the issue at hand. Still, every little  
thing can help.


On Jun 2, 2008, at 8:30 AM, Sean Chittenden wrote:

>> 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

Brian "Krow" Aker, brian at
Seattle, Washington                     <-- Me                <-- Software
You can't grep a dead tree.

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