Possible improvement to the slab allocator...

Paul Lindner lindner at inuus.com
Thu Oct 4 14:14:39 UTC 2007

[Sorry to revive this, slowly catching up with a backlog of mail.]

The number of entries in the slabs table is typically less than 48.  A
large array of size->slab would probably chew up the L2 cache and
well, it doesn't feel right..

I think it would be interesting to apply a function to the size input
and determine a minimum value to start searching the array, that could
save some cycles.

Either that or use a binary tree to speed up the search.

On Thu, Aug 23, 2007 at 02:17:00PM -0700, Tony Di Croce wrote:
> I think you could gain a little speed in your slab allocator by re-writing
> slabs_clsid() to use a lookup table.
> Basically, if you had an array with 1mb buckets, where each bucket was a
> pointer (so that the total size of the array would be 4mb), you could locate
> which slab to use simply by using the requested size as an index... It would
> save walking that array of up to POWER_LARGEST buckets.
> Since this function is called by do_slab_alloc(), it could potentially be a
> big win.
>    td

Paul Lindner        ||||| | | | |  |  |  |   |   |
lindner at inuus.com
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