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From dean gaudet <d...@arctic.org>
Subject Re: remaining CPU bottlenecks in 2.0
Date Thu, 06 Sep 2001 04:17:49 GMT
On Tue, 4 Sep 2001, Brian Pane wrote:

> * Collectively, stat and open comprise 5% of the total CPU time.
>   It would be faster to do open+fstat rather than stat+open (as
>   long as the server is delivering mostly 200s rather than 304s),
>   but that might be too radical a change.  Anybody have thoughts
>   on this?

linux' dcache makes either method about the same cost, but on other
kernels, and especially when NFS is involved (because of how NFS path
resolution occurs), the open/fstat is much better.  the trick would be to
cache open filehandles so that fstat can be used.

> * memset() is called mostly from apr_pcalloc(), which in turn is
>   used in too many places to yield any easy optimization opportunities.

sometimes folks are lazy and ask for zeroed memory out of habit, when they
could easily deal with garbage at less cost.

-dean


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