From: "H. Peter Anvin" <hpa@zytor.com>
To: Robert Hancock <hancockr@shaw.ca>
Cc: 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 17:48:52 -0700 [thread overview]
Message-ID: <44822DF4.5090504@zytor.com> (raw)
In-Reply-To: <448220CE.4030709@shaw.ca>
Robert Hancock wrote:
> 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.
>
If so, then merging doesn't matter either way.
-hpa
next prev parent reply other threads:[~2006-06-04 0:49 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 ` memcpy_toio on i386 using byte writes even when n%2==0 Robert Hancock
2006-06-04 0:48 ` H. Peter Anvin [this message]
[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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=44822DF4.5090504@zytor.com \
--to=hpa@zytor.com \
--cc=hancockr@shaw.ca \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox