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Pretty much nobody in the HPC sphere really uses hyperthreading, it's disabled in the BIOS on pretty much every HPC cluster I've ever used.
by physicsguy 5y ago
Pretty much nobody in the HPC sphere really uses hyperthreading, it's disabled in the BIOS on pretty much every HPC cluster I've ever used.
- reacharavindh 5y agoI don’t know why this insane rule of thumb still exists in the HPC world. True that some compute bound jobs that are not designed to make use of HT will be hurt by running in an HT environment. But, not all of HPC work is such purely compute bound. For a scientific field, it is ironic that someone perpetrates this blind rule. Do an A/B test with and without HT for your workload in hand and decide based on results….. As an example, in our test suite, we found that we get almost a 80% boost by turning on HT. The right rule is “HT may help or hurt your performance depending on workload. Test and decide”.
- the-dude 5y agoWhy is this a A/B test and not a regular test?
- physicsguy 5y agoWell, it's not such a bad idea for most cluster admins (me being one at a large UK University). Most of our compute time comes from a small number of very popular MPI parallelised applications, all of which suffer from worse (or at best equivalent) performance with hyperthreading.
- mhh__ 5y agoPoint is you can use it without worrying about security.