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From Brian Pane <>
Subject Re: load spikes revisited
Date Fri, 18 Jan 2002 07:04:09 GMT
Aaron Bannert wrote:

>On Thu, Jan 17, 2002 at 10:43:18PM -0800, Brian Pane wrote:
>>>prefork was changed to do a apr_poll before the accept, even in the single
>>>listen case, on Nov 10.  The polls seem to get added to the herd of selects 
>>>wake up several times a second for no real good reason.  We need to get rid 
>>>this poll once again.
>We should get rid of the poll() for S_L_U_A, but I think that would
>only treat the symptom, since it would come back when we had multiple

But in the multiple listener case, access to the poll will always
be serialized, so we won't be vulnerable to a thundering herd problem,

>  Personally, I think poll() is itself the problem, and my
>theory is that poll() has a thundering hurd problem on this particular
>version of FreeBSD. We can try this out by #undef'ing HAVE_POLL in
>srclib/apr/network_io/unix/poll.c, so we use select() instead, which
>is what we used to do before Nov 10th.

Yep, I think the poll is the problem too.  We ought to be
able to remove it altogether in the single-listener case,


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