On 02/03/2010 01:00 PM, Alan Cox wrote:
On Wed, 03 Feb 2010 12:52:34 -0500
Jeff Garzik<jgarzik@xxxxxxxxx> wrote:
On 02/03/2010 12:46 PM, Alan Cox wrote:
And indeed there was a patch I proposed in 2008 for this bounce
buffer latency: See the archive
Date: Fri, 29 Feb 2008 13:51:06 +0000
From: Alan Cox<alan@xxxxxxxxxxxxxxxxxxx>
To: linux-ide@xxxxxxxxxxxxxxx, jeff@xxxxxxxxxx
Subject: [RFC PATCH] libata: PIO via bounce buffer
although it doesn't deal with the dcache coherency issue and seems to
need a little tweaking to apply due to other changes
Yeah, I definitely liked the idea. I wonder if we could do the
allocation during port_start rather than at the time of bounce?
I actually got better numbers using kmalloc - no idea why - perhaps we
get a hot page ?
Seems logical. It surprises me, though, that being lockless and
completely avoiding the kmalloc infrastructure wasn't a bigger win. Was
this measured on UP?
If your approach has the lowest cost, let's get it in... I like
decisions informed by hard data. :)
Jeff
--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
