On Wed, 2017-01-18 at 03:30 -0700, Jan Beulich wrote: > > > > On 18.01.17 at 11:21, <george.dun...@citrix.com> wrote: > > On 18/01/17 00:30, Dario Faggioli wrote: > > > index ef8e0d8..d086264 100644 > > > --- a/xen/common/sched_credit2.c > > > +++ b/xen/common/sched_credit2.c > > > @@ -985,7 +985,7 @@ runq_tickle(const struct scheduler *ops, > > > struct csched2_vcpu *new, s_time_t now) > > > cpumask_andnot(&mask, &rqd->active, &rqd->idle); > > > cpumask_andnot(&mask, &mask, &rqd->tickled); > > > cpumask_and(&mask, &mask, new->vcpu->cpu_hard_affinity); > > > - if ( cpumask_test_cpu(cpu, &mask) ) > > > + if ( __cpumask_test_and_clear_cpu(cpu, &mask) ) > > > > Since we're micro-optimizing -- isn't test-and-clear a locked > > operation? > > Would that be more expensive than the if() statement below? > > cpumask_test_and_clear_cpu() is, but __cpumask_test_and_clear_cpu() > isn't. > George, ping?
Thanks and Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
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