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

Alexey Popov lol at chistydom.ru
Thu Nov 22 23:35:37 PST 2007


Hi.

Kris Kennaway wrote:

>> Now FreeBSD 7-STABLE ULE 8-core server without optimized PHP 
>> realpath_cache_size (producing 2000+ lstats per request) can handle up 
>> to ~24 rps as opposed to  max. 17 rps without your patch. %sys never 
>> grows over %user with your patch. On the server with optimized 
>> realpath_cache_size there's no visible influence of your patch.
> 
> You said "20" before for this configuration, so I'm a bit suspicious 
> about how seriously to treat your measurements :)
Sorry, my mistake. s/ULE/4BSD.

> Anyway, please obtain another lock profiling trace using the same 
> conditions as the previous one (same workload & duration, etc), so we 
> can compare what changed.
OK, I'll make it a little bit later.

Also I tried to find what else is slow in FreeBSD, I tried hwpmc as 
module and in kernel, but it fails with error:
pmc: Unknown Intel CPU.
module_register_init: MOD_LOAD (hwpmc, 0xffffffff804833e0, 
0xffffffff809338a0) error 78

This is related to 
http://www.freebsd.org/cgi/query-pr.cgi?pr=amd64%2F111994&cat=
and it is impossible to use hwpmc with modern CPUs.

Is kgmon profiling usable on FreeBSD 7?

With best regards,
Alexey Popov


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