Messages in this thread | | | From | "Miller, Mike (OS Dev)" <> | Subject | RE: [PATCH 1/1] cciss: set max scatter gather entries to 32 on P600 | Date | Wed, 14 Aug 2013 21:41:14 +0000 |
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-----Original Message----- From: James Bottomley [mailto:James.Bottomley@HansenPartnership.com] Sent: Wednesday, August 14, 2013 4:27 PM To: Miller, Mike (OS Dev); mikem@thumper.usa.hp.com Cc: Andrew Morton; Jens Axboe; LKML-scsi; LKML; thenzl@redhat.com; bubrown@redhat.com; scameron@beardog.cce.hp.com Subject: Re: [PATCH 1/1] cciss: set max scatter gather entries to 32 on P600
On Wed, 2013-08-14 at 15:52 -0500, Mike Miller wrote: > Patch 1/1 > > From: Mike Miller <mike.miller@hp.com> > > At one time we used to set the maximum number of scatter gather > elements on all Smart Array controllers to 32. At some point in time > the firmware began to write the "appropriate" value for each controller into the config table. > The cciss driver would then read that and set h->maxsgentries. > > h->maxsgentries = readl(&(h->cfgtable->MaxSGElements); > > On the P600 that value is 544. Under some workloads a significant > performance reduction may result. This patch forces the P600 to use > only 32 scatter gather elements. Other controllers are not affected. > > Signed-off-by: Mike Miller <mike.miller@hp.com> > Signed-off-by: Dwight (Bud) Brown <bubrown@redhat.com> > Signed-off-by: Tomas Henzl <thenzl@redhat.com> > Acked-by: Stephen M. Cameron <steve.cameron@hp.com>
I don't quite understand the signoff chain on this patch. For a one line patch, are you saying it has three authors?
James
The patch origin is unknown. I got it from Tomas and Bud who think it may have originated from HP. I cleaned it up, compile tested it, and sent it on. I'll review my procedures for future patches.
-- mikem
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