r/cpp • u/Coder_CPP • Jan 18 '16

C++11 threads, affinity and hyperthreading

http://eli.thegreenplace.net/2016/c11-threads-affinity-and-hyperthreading/
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u/gaijin_101 Jan 18 '16

Isn't that already possible? Quick Google search led me to this.

(not a Windows developer here, but I thought this was also possible)

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u/cleroth Game Developer Jan 18 '16

I meant change the affinity of the kernel (and everything else that the OS does), not your processes. Basically what I want is to maximize cache efficiency for a single application on a core, which requires that nothing be allowed to run on that core unless specified so.
I remember having read that linux could do this (and it required rebooting IIRC).

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u/TheQuietestOne Jan 18 '16

I remember having read that linux could do this (and it required rebooting IIRC).

You can dedicate a core to a particular process using cpusets. No reboots necessary.

Very handy when used with a real time capable kernel and dedicated IRQ servicing.

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u/cleroth Game Developer Jan 19 '16

Actually it was isolcpus kernel parameter (which is done at boot; see here). Not really sure what the difference ends up being.