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From David Reid <dr...@jetnet.co.uk>
Subject Re: [PATCH/CONTRIB] Shared Mem Hash Table
Date Sat, 07 Jul 2001 07:33:54 GMT

I'm going to try and add a configure option to allow us to add Electric Fence
support to apache, but will it be useful for APR as well?  It's a simple
enough patch as I'm not planning on much autodetection, simply having the user
identify where it is and have a couple of the more common locations checked if
they don't.  (I thought --with-ef=/path - thoughts??)

I'd be interested to know of other tools that people use that are available
for others here * on the list to use improving the code.  So far when pools
are sms the memory usage is higher than with pools alone (frighteningly so)
but this seems crazy given in testmem the same test with the same setup as per
the pools == sms code isn't anywhere near as hungry.  Probably some simplt
optimisation and it'll be fixed :)  Tools to let us know this and find the
bottlenecks are incredibly useful.

One of the things we really need to improve is our test suite.  Ian, are you
planning on adding your recent test app for pools?  We also need a better
buckets test app.  The one I quickly wrote in an hour or so at IBM isn't much
use :(

* By which I mean not costing $$$$


Cliff Woolley wrote:

> On Fri, 6 Jul 2001, Brian Pane wrote:
> > This morning, I instrumented the latest httpd-2.0 souce and found that
> > it's spending 41% of its CPU time in usr mode and 59% in sys when
> > delivering a 50KB, non-server-parsed file (on Linux, using sendfile).
> > For server-parsed requests, I've seen ratios as high as 70% usr, 30% sys.
> >
> > The bad news: the httpd is wasting a huge amount of CPU time in
> > user-space code (for an optimal httpd serving static files, the usr CPU
> > should approach zero; 41% is surprisingly high).  The good news: there's
> > an opportunity to cut the httpd's CPU utilization nearly in half by
> > tuning just the user-space code.
> The flip side of that, of course, is that we could probably also get rid
> of some useless/redundant system calls, thereby also reducing the time
> spent in sys CPU.
> --Cliff
> --------------------------------------------------------------
>    Cliff Woolley
>    cliffwoolley@yahoo.com
>    Charlottesville, VA

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