Re: [PATCH 0/4] slab: implement byte sized indexes for the freelistof a slab

From: Joonsoo Kim
Date: Wed Sep 04 2013 - 04:33:14 EST


On Tue, Sep 03, 2013 at 02:15:42PM +0000, Christoph Lameter wrote:
> On Mon, 2 Sep 2013, Joonsoo Kim wrote:
>
> > This patchset implements byte sized indexes for the freelist of a slab.
> >
> > Currently, the freelist of a slab consist of unsigned int sized indexes.
> > Most of slabs have less number of objects than 256, so much space is wasted.
> > To reduce this overhead, this patchset implements byte sized indexes for
> > the freelist of a slab. With it, we can save 3 bytes for each objects.
> >
> > This introduce one likely branch to functions used for setting/getting
> > objects to/from the freelist, but we may get more benefits from
> > this change.
> >
> > Below is some numbers of 'cat /proc/slabinfo' related to my previous posting
> > and this patchset.
>
> You may also want to run some performance tests. The cache footprint
> should also be reduced with this patchset and therefore performance should
> be better.

Yes, I did a hackbench test today, but I'm not ready for posting it.
The performance is improved for my previous posting and futher improvement is
founded by this patchset. Perhaps I will post it tomorrow.

Thanks.
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