[Beowulf] curiosity killed the cat

John Hearns John.Hearns at xma.co.uk
Thu Jun 2 01:42:42 PDT 2016

If anyone is interested in infrastructures using Ethernet like that,  have a look at JASMIN int he UK


Mellanox switching with 10Gbps to the edge and a rather large 40Gbps core infrastructure.
Put some of the switches in with my own fair hands!

From: Beowulf [beowulf-bounces at beowulf.org] on behalf of Stu Midgley [sdm900 at gmail.com]
Sent: 02 June 2016 05:01
To: Greg Lindahl
Cc: Beowulf List
Subject: Re: [Beowulf] curiosity killed the cat

just need to workout how to build large fat-trees with ethernet.

With 100G we get by with mlag for the spines (upto 640 hosts on 10g).

with our 40G/10G network, we are using ospf/mpls/vpls to give a static fat-tree...  30k lines of config applied to ~20 switches.  Nasty.

On Thu, Jun 2, 2016 at 11:57 AM, Greg Lindahl <lindahl at pbm.com<mailto:lindahl at pbm.com>> wrote:
On Thu, Jun 02, 2016 at 07:48:10AM +0800, Stu Midgley wrote:
> That's it.  As I said, I haven't used it since the early 00's.
> With 100Gb becoming common it might be time for these sort of MPI's to come
> back.

You could do better than these old interfaces, too... modern ethernet
chips have multiple send/receive queues, so you could hack up an
interface which looks a lot more like InfiniPath's one-queue-per-core
model -- the OpenIB code for InfiniPath also has code that maps M
cores:N queues if M>N.

-- greg

Dr Stuart Midgley
sdm900 at sdm900.com<mailto:sdm900 at sdm900.com>
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