Messages in this thread | | | Subject | Re: [PATCH] sched/fair: Add SMT4 group_smt_balance handling | From | Tim Chen <> | Date | Wed, 26 Jul 2023 20:11:18 -0700 |
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On Mon, 2023-07-17 at 20:28 +0530, Shrikanth Hegde wrote: > From: Tim Chen <tim.c.chen@linux.intel.com> > > For SMT4, any group with more than 2 tasks will be marked as > group_smt_balance. Retain the behaviour of group_has_spare by marking > the busiest group as the group which has the least number of idle_cpus. > > Also, handle rounding effect of adding (ncores_local + ncores_busy) > when the local is fully idle and busy group has more than 2 tasks. > Local group should try to pull at least 1 task in this case. > > Originally-by: Tim Chen <tim.c.chen@linux.intel.com> > Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> > Signed-off-by: Shrikanth Hegde <sshegde@linux.vnet.ibm.com> > --- > kernel/sched/fair.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 932e7b78894a..9502013abe33 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -9532,7 +9532,7 @@ static inline long sibling_imbalance(struct lb_env *env, > imbalance /= ncores_local + ncores_busiest; > > /* Take advantage of resource in an empty sched group */ > - if (imbalance == 0 && local->sum_nr_running == 0 && > + if (imbalance <= 1 && local->sum_nr_running == 0 && > busiest->sum_nr_running > 1) > imbalance = 2; > > @@ -9720,6 +9720,17 @@ static bool update_sd_pick_busiest(struct lb_env *env, > break; > > case group_smt_balance: > + /* no idle cpus on both groups handled by group_fully_busy below */ > + if (sgs->idle_cpus != 0 || busiest->idle_cpus != 0) { > + if (sgs->idle_cpus > busiest->idle_cpus) > + return false; > + if (sgs->idle_cpus < busiest->idle_cpus) > + return true; > + if (sgs->sum_nr_running <= busiest->sum_nr_running) > + return false; > + } > + break; > + > case group_fully_busy: > /* > * Select the fully busy group with highest avg_load. In
Thanks for the fix up patch.
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
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