Re: [PATCH]: Option to run cache reap in thread mode

Manfred Spraul
2004-06-16T17:25:24Z

Dimitri wrote:

>In the process of testing per/cpu interrupt response times and CPU availability,
>I've found that running cache_reap() as a timer as is done currently results
>in some fairly long CPU holdoffs.
>
What is fairly long?
If cache_reap() is slow than the caches are too large.
Could you limit cachep->free_limit and check if that helps? It's right
now scaled by num_online_cpus() - that's probably too much. It's
unlikely that all 500 cpus will try to refill their cpu arrays at the
same time. Something like a logarithmic increase should be sufficient.
Do you use the default batchcount values or have you increased the values?
I think the sgi ia64 system do not work with slab debugging, but please
check that debugging is off. Debug enabled is slow.

--
Manfred