From mboxrd@z Thu Jan 1 00:00:00 1970 From: Werner Almesberger Subject: Re: TOE brain dump Date: Mon, 4 Aug 2003 16:24:33 -0300 Sender: netdev-bounce@oss.sgi.com Message-ID: <20030804162433.L5798@almesberger.net> References: <20030802140444.E5798@almesberger.net> <3F2BF5C7.90400@us.ibm.com> <3F2C0C44.6020002@pobox.com> <20030802184901.G5798@almesberger.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jeff Garzik , Nivedita Singhvi , netdev@oss.sgi.com, linux-kernel@vger.kernel.org Return-path: To: "Eric W. Biederman" Content-Disposition: inline In-Reply-To: ; from ebiederm@xmission.com on Sun, Aug 03, 2003 at 01:21:09PM -0600 Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Eric W. Biederman wrote: > The optimized for low latency cases seem to have a strong > market in clusters. Clusters have captive, no, _desperate_ customers ;-) And it seems that people are just as happy putting MPI as their transport on top of all those link-layer technologies. > There is one place in low latency communications that I can think > of where TCP/IP is not the proper solution. For low latency > communication the checksum is at the wrong end of the packet. That's one of the few things ATM's AAL5 got right. But in the end, I think it doesn't really matter. At 1 Gbps, an MTU-sized packet flies by within 13 us. At 10 Gbps, it's only 1.3 us. At that point, you may well treat it as an atomic unit. > On that score it is worth noting that the next generation of > peripheral busses (Hypertransport, PCI Express, etc) are all switched. And it's about time for that :-) - Werner -- _________________________________________________________________________ / Werner Almesberger, Buenos Aires, Argentina werner@almesberger.net / /_http://www.almesberger.net/____________________________________________/