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SubjectRe: [Q] Default SLAB allocator
On Fri, 12 Oct 2012, Ezequiel Garcia wrote:

> >> SLUB is a non-starter for us and incurs a >10% performance degradation in
> >> netperf TCP_RR.
> >
>
> Where are you seeing that?
>

In my benchmarking results.

> Notice that many defconfigs are for embedded devices,
> and many of them say "use SLAB"; I wonder if that's right.
>

If a device doesn't require the smallest memory footprint possible (SLOB)
then SLAB is the right choice when there's a limited amount of memory;
SLUB requires higher order pages for the best performance (on my desktop
system running with CONFIG_SLUB, over 50% of the slab caches default to be
high order).

> Is there any intention to replace SLAB by SLUB?

There may be an intent, but it'll be nacked as long as there's a
performance degradation.

> In that case it could make sense to change defconfigs, although
> it wouldn't be based on any actual tests.
>

Um, you can't just go changing defconfigs without doing some due diligence
in ensuring it won't be deterimental for those users.


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