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| author | Tim Chen <tim.c.chen@linux.intel.com> | 2026-04-02 00:52:22 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-04-09 16:49:50 +0300 |
| commit | 15ad45fb80ca7fe67faf6b51dffce125a801cc5a (patch) | |
| tree | 88b7387a7f4412d238a712f5c1a6efaca81521e4 | |
| parent | 82c960aee304bf286552046b66d5b0b3933b2418 (diff) | |
| download | linux-15ad45fb80ca7fe67faf6b51dffce125a801cc5a.tar.xz | |
sched/cache: Count tasks prefering destination LLC in a sched group
During LLC load balancing, tabulate the number of tasks on each runqueue
that prefer the LLC contains the env->dst_cpu in a sched group.
For example, consider a system with 4 LLC sched groups (LLC0 to LLC3)
balancing towards LLC3. LLC0 has 3 tasks preferring LLC3, LLC1 has
2, and LLC2 has 1. LLC0, having the most tasks preferring LLC3, is
selected as the busiest source to pick tasks from.
Within a source LLC, the total number of tasks preferring a destination
LLC is computed by summing counts across all CPUs in that LLC. For
instance, if LLC0 has CPU0 with 2 tasks and CPU1 with 1 task preferring
LLC3, the total for LLC0 is 3.
These statistics allow the load balancer to choose tasks from source
sched groups that best match their preferred LLCs.
Co-developed-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/3d8502a33a753c4384b368f97f64ee70b1cea0db.1775065312.git.tim.c.chen@linux.intel.com
| -rw-r--r-- | kernel/sched/fair.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7d52cf0b85bd..cea625c79035 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10834,6 +10834,9 @@ struct sg_lb_stats { unsigned int nr_numa_running; unsigned int nr_preferred_running; #endif +#ifdef CONFIG_SCHED_CACHE + unsigned int nr_pref_dst_llc; +#endif }; /* @@ -11328,6 +11331,20 @@ static inline void update_sg_lb_stats(struct lb_env *env, if (cpu_overutilized(i)) sgs->group_overutilized = 1; +#ifdef CONFIG_SCHED_CACHE + if (sched_cache_enabled()) { + struct sched_domain *sd_tmp; + int dst_llc; + + dst_llc = llc_id(env->dst_cpu); + if (llc_id(i) != dst_llc) { + sd_tmp = rcu_dereference_all(rq->sd); + if (sd_tmp && (unsigned int)dst_llc < sd_tmp->llc_max) + sgs->nr_pref_dst_llc += sd_tmp->llc_counts[dst_llc]; + } + } +#endif + /* * No need to call idle_cpu() if nr_running is not 0 */ |