On Apr 30, 2007, at 3:31 PM, Ashley M. Kirchner wrote:
As far as understand their explanation is that they simply call
the thumbnail creation routine sequentially, one image at a time,
which in turn goes to PHP which then goes to Apache. And as far as
the OS is concerned, it received 1 single call from Apache to do
something, as opposed to multiple calls at the same time.
Would that be a reasonable explanation (of why their process
takes so long)? Because they're not spawning multiple calls ... ?
Oh, I see. So they're actually generating all thumbnails as they
generate the HTML that links to them? Yeah, that won't do. Not taking
advantage of all the processors is the least of their problems, they
also:
- have a single GET request which takes way, way, way too long to
respond - n_unprocessed_thumbnails*time_per_thumbnail >>> 0.1 sec for
n_unprocessed_thumbnails=800, even if there's no contention for the
processor
- are forking from Apache, which is a bad idea, especially if it's
multithreaded (are you using mpm_worker)? Big processes don't fork
quickly. Much better to use a library to do this.
--
Scott Lamb <http://www.slamb.org/>
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