
Ask HN: Generic guidelines on when to turn hyperthreading off? - totalperspectiv
Does anyone have any recent experience benchmarks different workloads with or without hyperthreading? Are there general characteristics that would indicate better runtime without hyperthreading?<p>All the resources I&#x27;ve found for this are pretty old and I&#x27;m curious if the state of hyperthreading has changed. The general guideline I&#x27;ve followed is:<p>If my workload can and will pin one or more threads for a long amount of time, it will be faster to have hyperthreading off.
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jepler
Compile workload seems to benefit from HT in general.

In our software build process (extremely parallel g++ of around 9000 files,
often cached by ccache), we have benchmarked with all threads, and with just 1
thread per core (via "taskset", not via BIOS disabling of HT), and if we don't
use the second thread on each core offered by HT, we lose 20% performance.

These results are from some old CPUs (i7-4930K) and some new CPUs (TR 1950x);
the 20% figure is based on the i7, and I don't have the figure handy for the
TR, but I believe it showed more benefit.

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benologist
I find Total War: Warhammer 2 runs snappier with my 4c/8t + bursting reduced
to 2c/2t + bursting. I think it can sustain the burst speed but I haven't
measured precisely.

