[CentOS] Slow performance
Scott Lamb
slamb at slamb.org
Tue May 1 00:49:34 UTC 2007
On Apr 30, 2007, at 5:07 PM, Ashley M. Kirchner wrote:
> I did a test running convert, single processor and got the
> following timing:
>
> ImageMagick 'convert', 1 process, JPEG (command line)
> real 8m35.515s
> user 6m18.674s
> sys 1m46.344s
>
>
> Then I wrote a small PHP script that does the same thing (read
> image, resize with constrain) and ran it through the command line,
> and got this:
>
> PHP, 1 process, JPEG (through PHP CLI)
> real 36m17.260s
> user 35m38.972s
> sys 0m30.651s
>
>
> Why oh why is it so much slower?! Is there something
> inheritedly slow within PHP that causes it to be so much slower
> (which in turn causes the Apache process to also take an incredible
> amount of time to finish the same task)?
Interesting. I'm not sure, as I don't use PHP. You might have better
luck getting an answer if you post your test scripts to a PHP list.
A few things I might do if I were trying to diagnose this:
- throw in a few getrusage()s to see which section of the script is
using the most time - maybe I'd get lucky and see one obviously wrong
- ltrace shows all calls to shared libraries - maybe it could uncover
something weird
- use whatever profiling tool is available for profiling PHP scripts.
(In Python, I'm fond of hotshot.)
- find out what underlying library they're using and try it from a
different language (Python, C, whatever) to see if the library or PHP
is the problem.
- compile the PHP interpreter itself with profiling and run it
through gprof to where the time went.
--
Scott Lamb <http://www.slamb.org/>
More information about the CentOS
mailing list