On 30 May 2014 08:34, Peter Zijlstra <[email protected]> wrote: > On Thu, May 29, 2014 at 09:56:24PM +0200, Vincent Guittot wrote: >> On 29 May 2014 16:02, Peter Zijlstra <[email protected]> wrote: >> > On Fri, May 23, 2014 at 05:53:05PM +0200, Vincent Guittot wrote: >> >> @@ -6052,8 +6006,8 @@ static inline void update_sd_lb_stats(struct lb_env >> >> *env, struct sd_lb_stats *sd >> >> * with a large weight task outweighs the tasks on the >> >> system). >> >> */ >> >> if (prefer_sibling && sds->local && >> >> - sds->local_stat.group_has_capacity) >> >> - sgs->group_capacity = min(sgs->group_capacity, 1U); >> >> + sds->local_stat.group_capacity > 0) >> >> + sgs->group_capacity = min(sgs->group_capacity, 1L); >> >> >> >> if (update_sd_pick_busiest(env, sds, sg, sgs)) { >> >> sds->busiest = sg; >> >> @@ -6228,7 +6182,7 @@ static inline void calculate_imbalance(struct >> >> lb_env *env, struct sd_lb_stats *s >> >> * have to drop below capacity to reach cpu-load >> >> equilibrium. >> >> */ >> >> load_above_capacity = >> >> - (busiest->sum_nr_running - busiest->group_capacity); >> >> + (busiest->sum_nr_running - busiest->group_weight); >> >> >> >> load_above_capacity *= (SCHED_LOAD_SCALE * >> >> SCHED_POWER_SCALE); >> >> load_above_capacity /= busiest->group_power; >> > >> > I think you just broke PREFER_SIBLING here.. >> >> you mean by replacing the capacity which was reflecting the number of >> core for SMT by the group_weight ? > > Right to in the first hunk we lower group_capacity to 1 when prefer_sibling, > then in the second hunk, you replace that group_capacity usage with > group_weight. > > With the end result that prefer_sibling is now ineffective.
ok > > That said, I fudged the prefer_sibling usage into the capacity logic, > mostly because I could and it was already how the SMT stuff was working. > But there is no reason we should continue to intertwine these two > things. > > So I think it would be good to have a patch that implements > prefer_sibling on nr_running separate from the existing capacity bits, > and then convert the remaining capacity bits to utilization (or activity > or whatever you did call it, see Morton's comments etc.). ok, i'm going to prepare such change > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
