From: Robert Hancock <hancockr@shaw.ca>
To: "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: memcpy_toio on i386 using byte writes even when n%2==0
Date: Sat, 03 Jun 2006 17:52:46 -0600 [thread overview]
Message-ID: <448220CE.4030709@shaw.ca> (raw)
In-Reply-To: <6inxv-4U2-17@gated-at.bofh.it>
H. Peter Anvin wrote:
> For something that generates I/O transactions, it's imperative to
> generate the smallest possible number of transactions. Furthermore,
> smaller than dword transactions aren't burstable, except at the
> beginning and end of a burst.
Well, theoretically for writes they could be, if the memory region was
prefetchable and the PCI chipset supported byte merge. It certainly
isn't optimal however.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@nospamshaw.ca
Home Page: http://www.roberthancock.com/
next parent reply other threads:[~2006-06-03 23:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <6ined-4gY-17@gated-at.bofh.it>
[not found] ` <6ined-4gY-21@gated-at.bofh.it>
[not found] ` <6inee-4gY-23@gated-at.bofh.it>
[not found] ` <6ined-4gY-15@gated-at.bofh.it>
[not found] ` <6inxv-4U2-17@gated-at.bofh.it>
2006-06-03 23:52 ` Robert Hancock [this message]
2006-06-04 0:48 ` memcpy_toio on i386 using byte writes even when n%2==0 H. Peter Anvin
[not found] <6gUec-3mb-7@gated-at.bofh.it>
[not found] ` <6gUec-3mb-5@gated-at.bofh.it>
[not found] ` <6icVy-56r-9@gated-at.bofh.it>
[not found] ` <6idov-5Tc-7@gated-at.bofh.it>
2006-05-31 0:55 ` Robert Hancock
2006-05-31 1:13 ` H. Peter Anvin
[not found] <6gMqr-8uW-23@gated-at.bofh.it>
2006-05-26 23:46 ` Robert Hancock
2006-05-29 7:38 ` H. Peter Anvin
2006-05-30 13:55 ` Chris Lesiak
2006-05-30 14:24 ` linux-os (Dick Johnson)
2006-05-26 15:29 Chris Lesiak
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