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GPUOpen-LibrariesAndSDKs / cpu-core-counts

A sample demonstrating how to correctly detect physical core and logical processor counts on AMD processors.
MIT License
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Use logical count for everything newer than dozer #4

Closed Artoria2e5 closed 3 years ago

Artoria2e5 commented 3 years ago

It probably doesn't make sense to kill the whole core detection completely, but we can still make everything a bit better by not limiting ourselves to dozer only. After all, Ken Mitchell 2017 does state that SMT is useful most of the time.

Fixes #2. Should be more in the spirit of @ThomasTheGerman's suggestion.

Artoria2e5 commented 3 years ago

Wait, when does AMD start having logical/core differences anyways? Isn't it just dozer with the clusters? What is this function good for anyways "usually" then, if all these SMT usually gets better performance? Shouldn't a README change be enough?

Eff this.

SylwesterZarebski commented 3 years ago

This patch is wrong. It should return logical core count when family is greater or equal than 0x15 not less or equal. Ryzen has family 0x17 (23).

Example: https://www.cpu-world.com/CPUs/Zen/AMD-Ryzen%207%201700.html

e0x70i commented 3 years ago

This patch is wrong. It should return logical core count when family is greater or equal than 0x15 not less or equal. Ryzen has family 0x17 (23).

Example: https://www.cpu-world.com/CPUs/Zen/AMD-Ryzen%207%201700.html

That’s exactly what the patch does.... (0x15 <= getCpuidFamily()) cpu family is greater or equal than 0x15 for that expression to return true.

SylwesterZarebski commented 3 years ago

Sorry, You're right, I replaced sides in my mind ;-), sorry!