From: David Daney <ddaney@caviumnetworks.com>
To: Michael Sundius <msundius@cisco.com>
Cc: linux-mips@linux-mips.org, "VomLehn, David" <dvomlehn@cisco.com>,
msundius@sundius.com
Subject: Re: memcpy and prefetch
Date: Tue, 27 Jan 2009 15:07:45 -0800 [thread overview]
Message-ID: <497F93C1.3090401@caviumnetworks.com> (raw)
In-Reply-To: <497F9214.1000609@cisco.com>
Michael Sundius wrote:
> I know this topic has been written about but so excuse me if I am
> redundant.
> I saw lots of talk in the archives but I don't know if a solution was
> ever arrived
> at. so:
>
> what is the current state of the use of prefetch in memcpy()? it seems that
> it is #undef-ed if CONFIG_DMA_COHERENT is not turned on.
>
> is this still because the memcpy does not check to prevent a prefetch of
> addresses beyond the end of the buffer?
>
> If so, what was the reason a solution was abandoned....
>
> also has anyone out there written a memcopy that does use prefetch
> intelligently (for mips32 that is)?
>
The Cavium OCTEON port overrides the default memcpy and does use
prefetch. It was recently merged (2.6.29-rc2). Look at octeon-memcpy.S
I have thought that memcpy could be generated by mm/page.c as copy_page
and clear_page are.
David Daney
next prev parent reply other threads:[~2009-01-27 23:09 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-27 23:00 memcpy and prefetch Michael Sundius
2009-01-27 23:07 ` David Daney [this message]
2009-01-28 10:37 ` Ralf Baechle
2009-01-28 15:28 ` Atsushi Nemoto
2009-01-28 18:30 ` Ralf Baechle
2009-01-29 12:36 ` Atsushi Nemoto
2009-01-29 15:58 ` Ralf Baechle
2009-01-30 3:39 ` David VomLehn (dvomlehn)
2009-01-30 3:39 ` David VomLehn (dvomlehn)
2009-02-04 21:27 ` Ralf Baechle
2009-02-04 21:27 ` Ralf Baechle
2009-02-05 15:31 ` Atsushi Nemoto
2009-01-28 19:28 ` Michael Sundius
2009-01-28 19:54 ` David Daney
2009-01-28 21:52 ` Chad Reese
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