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

Krassimir Slavchev krassi at bulinfo.net
Fri Nov 23 03:06:47 PST 2007


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Ivan Voras wrote:
> 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:

That's true but if the tests are same then they can be compared.

> 
> - 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)

This is not recommended for production systems.

> - 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.

Yes, may be it is easier to write perl/php scripts.

> 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.
> 
Yes, that is true for mod_perl too.

However, it is hard to simulate real workload.

I will have 2 2xQuad Core(X5450) with 8G RAM systems (DL380G5) soon and
will have about a month to play with them before put in production. If
someone wish I can run specific test on them.

Best Regards

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