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

[Manfred Spraul]

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

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