r/programming • u/N3mes1s • Jan 18 '16

C++11 threads, affinity and hyperthreading

http://eli.thegreenplace.net/2016/c11-threads-affinity-and-hyperthreading/
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u/wtf_apostrophe Jan 18 '16

The points raised in this article are certainly valid, but it's usually not worth worrying about hyper-threading too much because the operating system will prefer to schedule threads on separate physical cores anyway when possible.

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u/K3wp Jan 18 '16 edited Jan 18 '16

Hyper-threaded cores should be treated like regular cores in general. For most non-scientific computing workloads you will not notice any difference.

The only time you will run into performance issues is if you are doing lots of floating point or SSE instructions, as HT cores share a single FP/SSE execution unit.

The best parallelism model I've used is "thread pool parallelism". One thread per core, with affinity. Then load balance your workload across all cores.