Messages in this thread | | | Date | Tue, 2 Mar 2021 10:10:32 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] sched/fair: Prefer idle CPU to cache affinity |
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On Tue, Mar 02, 2021 at 01:09:46PM +0530, Srikar Dronamraju wrote: > > Oh, could be, I didn't grep :/ We could have core code keep track of the > > smt count I suppose. > > Could we use cpumask_weight(cpu_smt_mask(this_cpu)) instead?
cpumask_weight() is potentially super expensive. With CPUMASK_OFFSTACK you get at least one more cache miss and then the bitmap might be really long.
Best to compute the results once and use it later.
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