-----Original Message----- From: James Bottomley [mailto:James.Bottomley@xxxxxxxxxxxxxxxxxxxxx] Sent: Wednesday, August 14, 2013 4:27 PM To: Miller, Mike (OS Dev); mikem@xxxxxxxxxxxxxxxxxx Cc: Andrew Morton; Jens Axboe; LKML-scsi; LKML; thenzl@xxxxxxxxxx; bubrown@xxxxxxxxxx; scameron@xxxxxxxxxxxxxxxxxx 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@xxxxxx> > > 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@xxxxxx> > Signed-off-by: Dwight (Bud) Brown <bubrown@xxxxxxxxxx> > Signed-off-by: Tomas Henzl <thenzl@xxxxxxxxxx> > Acked-by: Stephen M. Cameron <steve.cameron@xxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
