From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: mike.miller@hp.com, mikem@thumper.usa.hp.com
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>,
LKML-scsi <linux-scsi@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
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
Date: Wed, 14 Aug 2013 14:27:07 -0700 [thread overview]
Message-ID: <1376515627.2028.41.camel@dabdike.int.hansenpartnership.com> (raw)
In-Reply-To: <20130814205236.GB23042@beardog.cce.hp.com>
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
next prev parent reply other threads:[~2013-08-14 21:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-14 20:52 Mike Miller
2013-08-14 21:27 ` James Bottomley [this message]
2013-08-14 21:41 ` Miller, Mike (OS Dev)
2013-08-15 11:21 ` Tomas Henzl
2013-08-15 20:11 ` Bud Brown
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