From: Tejun Heo <tj@kernel.org>
To: Shaohua Li <shaohua.li@intel.com>
Cc: linux-ide <linux-ide@vger.kernel.org>, Jeff Garzik <jgarzik@pobox.com>
Subject: Re: [RFC] add DMA setup FIS auto-activate feature
Date: Thu, 23 Jul 2009 12:50:37 +0900 [thread overview]
Message-ID: <4A67DE0D.5040101@kernel.org> (raw)
In-Reply-To: <1248320734.9035.22.camel@sli10-desk.sh.intel.com>
Shaohua Li wrote:
> hi,
> The SATA spec defines DMA setup FIS auto-activate optimization for FPDMA
> transfers. I had an attempt to add it, though my test doesn't show obvious
> performance improvement (not worse too), I wonder why not add this feature?
>
> Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Eh... It's not clear whether all controllers support AA and it's also
not clear whether devices which claim to support AA actually work
properly when AA is enabled. For optional features in ATA(PI), the
best we can do is probably to allow enabling it from userland or bios.
It used to be better for ATA compared to ATAPI but with the
introduction of SSDs, the situation has gotten worse rapidly. :-(
Thanks.
--
tejun
next prev parent reply other threads:[~2009-07-23 3:51 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-23 3:45 [RFC] add DMA setup FIS auto-activate feature Shaohua Li
2009-07-23 3:50 ` Tejun Heo [this message]
2009-07-23 3:59 ` Jeff Garzik
2009-07-23 5:40 ` Shaohua Li
2009-07-23 5:45 ` Tejun Heo
2009-07-23 6:07 ` Jeff Garzik
2009-07-23 6:12 ` Tejun Heo
2009-07-23 6:48 ` Jeff Garzik
2009-07-23 7:25 ` Shaohua Li
2009-07-23 18:07 ` Robert Hancock
2009-07-23 18:11 ` Jeff Garzik
2009-07-23 20:52 ` Tejun Heo
2009-07-24 9:12 ` Shaohua Li
2009-07-25 0:47 ` Tejun Heo
2009-07-27 1:24 ` Shaohua Li
2009-07-27 1:31 ` Tejun Heo
2009-07-29 1:20 ` Jeff Garzik
2009-07-23 6:18 ` Robert Hancock
2009-07-23 9:55 ` Sergei Shtylyov
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