From: Dmitry Yusupov <dmitry_yus@yahoo.com>
To: Grant Grundler <grundler@parisc-linux.org>
Cc: "open-iscsi@googlegroups.com" <open-iscsi@googlegroups.com>,
"David S. Miller" <davem@davemloft.net>,
mpm@selenic.com, andrea@suse.de, michaelc@cs.wisc.edu,
James.Bottomley@HansenPartnership.com,
ksummit-2005-discuss@thunk.org, netdev@oss.sgi.com
Subject: Re: Linux support for RDMA (was: [Ksummit-2005-discuss] Summary of 2005 Kernel Summit Proposed Topics)
Date: Mon, 04 Apr 2005 09:54:10 -0700 [thread overview]
Message-ID: <1112633650.9559.142.camel@beastie> (raw)
In-Reply-To: <20050404063456.GB30855@colo.lackof.org>
On Mon, 2005-04-04 at 00:34 -0600, Grant Grundler wrote:
> On Sun, Apr 03, 2005 at 05:56:11PM -0700, Dmitry Yusupov wrote:
> > I do not get your concern with memory BW. With good AMD box V40Z(SUN)
> > you can get 5.3GBytes/sec. Even with 10Gbps full speed you have 80%
> > left. PCI-X BUS BW is bigger concern...
>
> Yes and No. PCI-X isn't fast enough but the data only crosses
> the PCI-X bus once. Think about the data flow:
> 1) DMA to RAM
yes.
> 2) load into CPU cache
yes.
> 3) store back into RAM
no. we are talking about receive side optimization only.
why do you think store back into RAM comes to the picture?
also keep in mind that we have huge L2 & L3 caches today and write
operation is usually very well buffered.
> We are down to 40% left...graphics folks won't like you.
>
> grant
>
next prev parent reply other threads:[~2005-04-04 16:54 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-02 19:07 [Ksummit-2005-discuss] Summary of 2005 Kernel Summit ProposedTopics Asgeir Eiriksson
2005-04-02 19:14 ` Ming Zhang
2005-04-04 0:56 ` Linux support for RDMA (was: [Ksummit-2005-discuss] Summary of 2005 Kernel Summit Proposed Topics) Dmitry Yusupov
2005-04-04 6:34 ` Grant Grundler
2005-04-04 7:10 ` David S. Miller
2005-04-04 12:58 ` Ming Zhang
2005-04-04 16:31 ` Grant Grundler
2005-04-04 12:56 ` Ming Zhang
2005-04-04 16:54 ` Dmitry Yusupov [this message]
2005-04-04 19:11 ` Grant Grundler
-- strict thread matches above, loose matches on Subject: below --
2005-04-05 22:19 jaganav
2005-04-02 7:29 jaganav
2005-04-02 18:27 ` Matthew Wilcox
2005-04-03 1:26 ` Grant Grundler
2005-04-05 15:04 ` Rik van Riel
2005-04-01 2:13 jaganav
2005-04-01 23:43 ` Stephen Hemminger
2005-04-02 1:37 ` jaganav
2005-04-02 5:27 ` Greg KH
2005-04-02 6:02 ` Greg KH
2005-04-02 15:01 ` Andrea Arcangeli
2005-04-04 16:50 ` Stephen Hemminger
[not found] <4241D106.8050302@cs.wisc.edu>
[not found] ` <20050324101622S.fujita.tomonori@lab.ntt.co.jp>
[not found] ` <1111628393.1548.307.camel@beastie>
[not found] ` <20050324113312W.fujita.tomonori@lab.ntt.co.jp>
[not found] ` <1111633846.1548.318.camel@beastie>
[not found] ` <20050324215922.GT14202@opteron.random>
[not found] ` <424346FE.20704@cs.wisc.edu>
[not found] ` <20050324233921.GZ14202@opteron.random>
[not found] ` <20050325034341.GV32638@waste.org>
[not found] ` <20050327035149.GD4053@g5.random>
2005-03-27 5:48 ` [Ksummit-2005-discuss] Summary of 2005 Kernel Summit Proposed Topics Matt Mackall
2005-03-27 6:33 ` Dmitry Yusupov
2005-03-27 6:46 ` David S. Miller
2005-03-28 19:45 ` Roland Dreier
[not found] ` <1112042936.5088.22.camel@beastie>
2005-03-28 22:32 ` Benjamin LaHaise
2005-03-29 3:19 ` Linux support for RDMA (was: [Ksummit-2005-discuss] Summary of 2005 Kernel Summit Proposed Topics) Roland Dreier
2005-03-30 16:00 ` Benjamin LaHaise
2005-03-29 3:14 ` Roland Dreier
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