Re: tbench regression - Why process scheduler has impact on tbenchand why small per-cpu slab (SLUB) cache creates the scenario?

From: Christoph Lameter
Date: Tue Sep 11 2007 - 16:21:25 EST


On Tue, 11 Sep 2007, Nick Piggin wrote:

> The impression I got at vm meeting was that SLUB was good to go :(

Its not? I have had Intel test this thoroughly and they assured me that it
is up to SLAB. This particular case is an synthetic tests for a PAGE_SIZE
alloc and SLUB was not optimized for that case because PAGE_SIZEd
allocations should be handled by the page allocators. Quicklists were
introduced for the explicit purpose to get these messy page sized cases
out of the slab allocators.

> But slab allocations don't really control the macro behaviour of a
> benchmark like that so much. So don't wait until something happens
> with the scheduler, fix it now.

Ok so you are for pushing in the page allocator pass through patch from mm
into rc6? Isnt it a bit late for such a change? I would think that 2.6.24
is early enough.
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