From: Anton Blanchard <anton@samba.org>
To: "David S. Miller" <davem@redhat.com>
Cc: scott.feldman@intel.com, haveblue@us.ibm.com, hdierks@us.ibm.com,
dwg@au1.ibm.com, linux-kernel@vger.kernel.org,
milliner@us.ibm.com, ricardoz@us.ibm.com, twichell@us.ibm.com,
netdev@oss.sgi.com
Subject: Re: e1000 performance hack for ppc64 (Power4)
Date: Sat, 14 Jun 2003 10:55:34 +1000 [thread overview]
Message-ID: <20030614005534.GF32097@krispykreme> (raw)
In-Reply-To: <20030613.165250.41635765.davem@redhat.com>
> So Anton, when the PCI controller gets a set of sub-cacheline word
> reads from the device, it reads the value from memory once for every
> one of those words? ROFL, if so... I can't believe they wouldn't
> put caches on the PCI controller for this, at least a one-behind that
> snoops the bus :(
There is a cache in the host bridge and the PCI-PCI bridge. I dont
think we go back to memory for sub cacheline reads.
What I think is happening is that we arent tripping the prefetch logic.
We should take a latency hit for only the first cacheline at which point
the host bridge decides to start prefetching for us. If not then we take
take the latency hit on each transaction.
Anton
next prev parent reply other threads:[~2003-06-14 0:44 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-06-13 23:52 e1000 performance hack for ppc64 (Power4) Feldman, Scott
2003-06-13 23:52 ` David S. Miller
2003-06-14 0:55 ` Anton Blanchard [this message]
2003-06-14 1:34 ` David S. Miller
2003-06-14 0:03 ` Anton Blanchard
-- strict thread matches above, loose matches on Subject: below --
2003-06-16 18:56 Feldman, Scott
2003-06-16 18:21 Feldman, Scott
2003-06-16 18:30 ` Dave Hansen
2003-06-15 14:40 Herman Dierks
2003-06-15 14:44 ` David S. Miller
2003-06-16 16:17 ` Nivedita Singhvi
2003-06-15 14:32 Herman Dierks
2003-06-13 22:13 Feldman, Scott
2003-06-13 17:03 Herman Dierks
2003-06-13 15:17 Herman Dierks
2003-06-13 16:21 ` Dave Hansen
2003-06-13 22:38 ` Anton Blanchard
2003-06-13 22:46 ` David S. Miller
2003-06-13 23:18 ` Anton Blanchard
2003-06-14 1:52 ` Lincoln Dale
2003-06-14 5:41 ` David S. Miller
2003-06-14 5:52 ` Lincoln Dale
2003-06-14 6:08 ` David S. Miller
2003-06-14 6:14 ` David S. Miller
2003-06-14 6:27 ` William Lee Irwin III
2003-06-14 17:08 ` Greg KH
2003-06-14 17:19 ` Greg KH
2003-06-14 17:21 ` Riley Williams
2003-06-15 3:01 ` David S. Miller
2003-06-14 5:16 ` Nivedita Singhvi
2003-06-14 5:36 ` David S. Miller
2003-06-13 1:16 Feldman, Scott
2003-06-13 23:15 ` Anton Blanchard
2003-06-12 3:32 David Gibson
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