[Beowulf] Roadrunner shutdown

Lux, Jim (337C) james.p.lux at jpl.nasa.gov
Mon Apr 1 17:20:47 PDT 2013


A commenter on Slashdot (I know, not always the most accurate of sources..) gives
444 Mflop/W for RR and 2143 MFLOP/W for Titan.  Sequoia comes in at just over 2000. K is 830.
That's a pretty big difference. 

I get 280 for Cielo (1100TF/3980kW) which is worse than Roadrunner. 

I suspect it's a combination of factors..  power consumption is one, age is another.  At a certain point, you start having maintenance issues (Prentice's  #5 (and maybe the half dozen people who really understand how box A works are now working on box B, Prentice's #3, below), and it's time to start over.

It might also be an issue of problem size that you can grind on.  The top500 is about a particular metric.  Processor speeds, per se, haven't been going up as fast as say disk drive size/speed, or solid state drives, or interconnects, which have gotten more sophisticated.

And, no, it's being sent to *north* Korea, where  it will bring the primitive electrical grid to its knees.<grin>


Jim Lux

-----Original Message-----
From: beowulf-bounces at beowulf.org [mailto:beowulf-bounces at beowulf.org] On Behalf Of Prentice Bisbal
Sent: Monday, April 01, 2013 8:10 AM
To: beowulf at beowulf.org
Subject: Re: [Beowulf] Roadrunner shutdown

Interesting. I know Roadrunner is still near the top of the Top500 list, so I did a quick check of it's standings. Here's how Roadrunner compares to Cielo, it's replacement, based on the the November 2012 Top500 and
Green500 lists:

Roadrunner:
Top500 ranking:             #22
Top500 Rmax:                 1042 TFLOP/s
Green500 Ranking:         #148
Green500 MFLOPS/W:    444.35
Total Power:                    2,345 KW

Cielo:
Top500 ranking:              #18
Top500 Rmax:                1053 TFLOP/s
Green500 Ranking:        #195
Green500 MFLOPS/W:    278.98 KW
Total Power:                    3980

Clearly there's something more to this story. Cielo is only 1% faster than Roadrunner, and produces 38.2 % LESS FLOPS/W. In most cases, the energy efficiency of RoadRunner would trump the 1% performance improvement of Cielo. I'm speculating the decommissioning of RoadRunner is driven more by people and politics than any technical issues. I think any of these reasons could be valid:

1. The contract for building/running RoadRunner mandates its decommissioning at this time.

2. Support agreement with IBM has ended, and it's either too costly to renew, or IBM isn't interested in renewing it.

3. The limited knowledgebase created by this unique system made it too difficult to either maintain or optimize codes for it (user base is too small),  casuing it to be underutilized. (This could be argued to be a technical issue or a people issue).

4. The space occupied by RoadRunner is needed for an even bigger system (Exascale, anyone?).

5. No more spare parts availability.

6. Secretly being moved to South Korea to piss off North Korea even more than the B-2 bombers did.

Any other ideas, or does anyone know the real reason driving this?  I'm sure HPCWire or some other news source will provide a more detailed explanation soon.

Prentice

On 04/01/2013 06:45 AM, John Hearns wrote:
> I now we have all seen this through different sources.
> However interesting as this is a main stream news item, and it is 
> pretty balanced.
>
> http://www.bbc.co.uk/news/technology-21993132
>

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