2 x quad-core system is slower that 2 x dual core on FreeBSD

Ivan Voras ivoras at freebsd.org
Fri Nov 23 02:16:46 PST 2007

On 23/11/2007, Krassimir Slavchev <krassi at bulinfo.net> wrote:

> Would someone define what exact tests to be performed.
> Ok, using "ab" is fine but with what parameters it is used and against
> what, script or static html? It will be good to have written some perl,

In this thread, it's always PHP code, with database backends.

> php ... scripts or C programs which simulates some kind of 'real world'
> work.

The problem is that a realistic applications does a lot of things that
are not easily simulated:

- usually has a lot of code, lots of include files, libraries, etc.
(so it stresses file systems, as was shown with fstat() in the thread
- the code is most likely checking for changes in PHP libraries)
- uses a database, which is populated with real-world data (so it has
a lot of IPC of very varied sizes)
- uses some kind of caching, both of compiled PHP code (eAccelerator,
pecl-APC) and of data (eAccelerator, memcached) (which uses SysV SHM
and IPC).

Reducing all that to a C file that does all of it is very nontrivial.
For "classic" setups with mod_php, it's not uncommon that httpd
processes grow to 100 MB or more each, with all the heavy stuff
brought in.

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