On Mon, Mar 01, 2021 at 10:36:01PM +0530, Srikar Dronamraju wrote: > * Peter Zijlstra <[email protected]> [2021-03-01 16:44:42]: > > > On Sat, Feb 27, 2021 at 02:56:07PM -0500, Rik van Riel wrote: > > > On Fri, 2021-02-26 at 22:10 +0530, Srikar Dronamraju wrote: > > > > > > + if (sched_feat(WA_WAKER) && tnr_busy < tllc_size) > > > > + return this_cpu; > > > > > > I wonder if we need to use a slightly lower threshold on > > > very large LLCs, both to account for the fact that the > > > select_idle_cpu code may not find the single idle CPU > > > among a dozen busy ones, or because on a system with > > > hyperthreading we may often be better off picking another > > > LLC for HT contention issues? > > > > > > Maybe we could use "tnr_busy * 4 < > > > tllc_size * 3" or > > > something like that? > > > > How about: > > > > tnr_busy < tllc_size / topology_max_smt_threads() > > > > ? > > Isn't topology_max_smt_threads only for x86 as of today? > Or Am I missing out?
Oh, could be, I didn't grep :/ We could have core code keep track of the smt count I suppose.
