Messages in this thread | | | Date | Mon, 17 Oct 2022 19:35:27 -0700 | From | Ricardo Neri <> | Subject | Re: [PATCH 0/4] sched/fair: Avoid unnecessary migrations within SMT domains |
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On Thu, Aug 25, 2022 at 03:55:25PM -0700, Ricardo Neri wrote: > Intel processors that support Intel Turbo Boost Max 3.0 use asym_packing > to assign higher priorities to CPUs with higher maximum frequencies. It > artificially assigns, however, a lower priority to the higher-numbered > SMT siblings to ensure that they are used last. > > This results in unnecessary task migrations within the SMT domains. > > On processors with a mixture of higher-frequency SMT cores and lower- > frequency non-SMT cores (such as Intel hybrid processors), a lower- > priority CPU pulls tasks from the higher-priority cores if more than one > SMT sibling is busy. > > Do not use different priorities for each SMT sibling. Instead, tweak the > asym_packing load balancer to recognize SMT cores with more than one > busy sibling and let lower-priority CPUs pull tasks. > > Removing these artificial priorities avoids superfluous migrations and > lets lower-priority cores inspect all SMT siblings for the busiest queue.
Hello. I'd like to know if there are any comments on these patches. This patchset is a requisite for the IPC classes of tasks patchset [1].
Thanks in advance! Ricardo
[1]. https://lore.kernel.org/lkml/20220909231205.14009-5-ricardo.neri-calderon@linux.intel.com/T/
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