Monday, 13 September 2010

Do you want ice with your supercomputer?

[Originally posted on The NAG Blog]

Would you like ice with your drink?” It’s a common question of course. One that divides people – few will think “I don’t mind” – most have a firm preference one way or the other. There are people who hate ice with their drink and those who freak if there is none. National stereotypes have a role to play – in the USA the question is not always asked – it’s assumed you want ice with everything. In the UK, you often have to ask specifically to get ice.

Yet the role of ice in making our drinks chilled is misleading. I once had a discussion with a leading American member of the international HPC community about this. “No ice”, he was complaining as we headed out of a European country, “they had no ice for the drink”.

I don’t get this obsession with ice”, I chipped in. “What?!” He looked at me as if I were mad. “Why do you like your coke warm?

Ah, but that’s just it”, I replied. “I hate warm drinks – I really like my coke chilled. But surely, in this modern world over a century after the invention of the refrigerator, it’s not unreasonable to expect the fluid to be chilled – without the need to drop lumps of solid water into it?

Ah, fair point”, he conceded.

What has this got to do with supercomputing? Perhaps the common thread is that usually we just accept the habitual choices of ways to do things – and don’t often step back to think – “are those the only choices?

Maybe we should step back a little more often and ask ourselves what we are trying to achieve with HPC – and are the usual choices the only ways forward? Or are there different ways to approach the problem that will deliver simpler, better or cheaper performance?

Perhaps your business/research goals mean you need to conduct more complex modelling or you need faster performance. Maybe the drive of computing technology towards many-core processors rather than faster processors is limiting your ability to achieve this. (I have had several conversations recently, where companies are buying older technology because their software won’t run on multicore).

The “ice or no ice” question might be whether or not to upgrade your HPC with the latest multicore processors. But what about the “just chill the fluid” option? Well, how about upgrading the software instead, or as well?

NAG has plenty of case studies to show where enhancements to software have achieved huge gains in performance or capability (e.g.,

Sometimes buying more compute power is the right answer. Sometimes, extracting more efficient performance from what you have is the answer. Bringing them together - a balance of hardware upgrades and software innovations might well give you the best chance of optimising cost efficiency, performance and sustainability of performance.

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