Re: [PATCH 03/13] scsi: unify allocation of scsi command and sense buffer
From: Nick Piggin
Date: Mon May 25 2009 - 07:33:04 EST
On Mon, May 25, 2009 at 11:15:42AM +0300, Pekka Enberg wrote:
> On Mon, May 25, 2009 at 10:30 AM, Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:
> > Fold the sense buffer into the command, thereby eliminating a slab
> > allocation and free per command.
> > Signed-off-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
> Interesting. I wonder how this affects the SLAB vs. SLUB regression
> people are seeing on high end machines in OLTP benchmarks.
It could improve it. I think these (bios, requests, commands etc) allocations
are what SLUB has trouble with in that workload, so eliminating one of them
should help it. I guess it will help the other allocators as well, but maybe
a smaller relative improvement?
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/