From: Peter Zijlstra <peterz@infradead.org>
To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Len Brown <len.brown@intel.com>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Aubrey Li <aubrey.li@linux.intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Ricardo Neri <ricardo.neri@intel.com>,
Quentin Perret <qperret@google.com>,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
linux-kernel@vger.kernel.org, Aubrey Li <aubrey.li@intel.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>
Subject: Re: [PATCH v3 5/6] sched/fair: Consider SMT in ASYM_PACKING load balance
Date: Fri, 14 May 2021 11:47:45 +0200 [thread overview]
Message-ID: <YJ5HQR943rSFsLxw@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210513154909.6385-6-ricardo.neri-calderon@linux.intel.com>
On Thu, May 13, 2021 at 08:49:08AM -0700, Ricardo Neri wrote:
> include/linux/sched/topology.h | 1 +
> kernel/sched/fair.c | 101 +++++++++++++++++++++++++++++++++
> 2 files changed, 102 insertions(+)
>
> diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
> index 8f0f778b7c91..43bdb8b1e1df 100644
> --- a/include/linux/sched/topology.h
> +++ b/include/linux/sched/topology.h
> @@ -57,6 +57,7 @@ static inline int cpu_numa_flags(void)
> #endif
>
> extern int arch_asym_cpu_priority(int cpu);
> +extern bool arch_asym_check_smt_siblings(void);
>
> struct sched_domain_attr {
> int relax_domain_level;
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index c8b66a5d593e..3d6cc027e6e6 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -106,6 +106,15 @@ int __weak arch_asym_cpu_priority(int cpu)
> return -cpu;
> }
>
> +/*
> + * For asym packing, first check the state of SMT siblings before deciding to
> + * pull tasks.
> + */
> +bool __weak arch_asym_check_smt_siblings(void)
> +{
> + return false;
> +}
> +
> /*
> * The margin used when comparing utilization with CPU capacity.
> *
> @@ -8458,6 +8550,9 @@ sched_asym(struct lb_env *env, struct sd_lb_stats *sds, struct sg_lb_stats *sgs
> if (group == sds->local)
> return false;
>
> + if (arch_asym_check_smt_siblings())
> + return asym_can_pull_tasks(env->dst_cpu, sds, sgs, group);
> +
> return sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu);
> }
So I'm thinking that this is a property of having ASYM_PACKING at a core
level, rather than some arch special. Wouldn't something like this be
more appropriate?
---
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -57,7 +57,6 @@ static inline int cpu_numa_flags(void)
#endif
extern int arch_asym_cpu_priority(int cpu);
-extern bool arch_asym_check_smt_siblings(void);
struct sched_domain_attr {
int relax_domain_level;
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -107,15 +107,6 @@ int __weak arch_asym_cpu_priority(int cp
}
/*
- * For asym packing, first check the state of SMT siblings before deciding to
- * pull tasks.
- */
-bool __weak arch_asym_check_smt_siblings(void)
-{
- return false;
-}
-
-/*
* The margin used when comparing utilization with CPU capacity.
*
* (default: ~20%)
@@ -8550,7 +8541,8 @@ sched_asym(struct lb_env *env, struct sd
if (group == sds->local)
return false;
- if (arch_asym_check_smt_siblings())
+ if ((sds->local->flags & SD_SHARE_CPUCAPACITY) ||
+ (group->flags & SD_SHARE_CPUCAPACITY))
return asym_can_pull_tasks(env->dst_cpu, sds, sgs, group);
return sched_asym_prefer(env->dst_cpu, group->asym_prefer_cpu);
next prev parent reply other threads:[~2021-05-14 9:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-13 15:49 [PATCH v3 0/6] sched/fair: Fix load balancing of SMT siblings with ASYM_PACKING Ricardo Neri
2021-05-13 15:49 ` [PATCH v3 1/6] sched/topology: Introduce sched_group::flags Ricardo Neri
2021-05-13 15:49 ` [PATCH v3 2/6] sched/fair: Optimize checking for group_asym_packing Ricardo Neri
2021-05-13 15:49 ` [PATCH v3 3/6] sched/fair: Provide update_sg_lb_stats() with sched domain statistics Ricardo Neri
2021-05-13 15:49 ` [PATCH v3 4/6] sched/fair: Carve out logic to mark a group for asymmetric packing Ricardo Neri
2021-05-17 14:21 ` Dietmar Eggemann
2021-05-18 19:18 ` Ricardo Neri
2021-05-13 15:49 ` [PATCH v3 5/6] sched/fair: Consider SMT in ASYM_PACKING load balance Ricardo Neri
2021-05-14 9:47 ` Peter Zijlstra [this message]
2021-05-15 2:14 ` Ricardo Neri
2021-05-18 19:07 ` Ricardo Neri
2021-05-19 9:59 ` Peter Zijlstra
2021-05-19 11:09 ` Nicholas Piggin
2021-05-19 12:05 ` Srikar Dronamraju
2021-05-17 15:18 ` Dietmar Eggemann
2021-05-18 19:10 ` Ricardo Neri
2021-05-17 22:28 ` Joel Fernandes
2021-05-17 22:34 ` Joel Fernandes
2021-05-13 15:49 ` [PATCH v3 6/6] x86/sched: Enable SMT checks for asymmetric packing in load balancing Ricardo Neri
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