From: Changwoo Min Date: Fri, 31 Jan 2025 07:09:31 +0000 (+0900) Subject: sched_ext: Add an event, SCX_EV_DISPATCH_KEEP_LAST X-Git-Tag: v6.15-rc1~227^2~40 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7125660bc16b7e87665bc859e7337388bdb63e0a;p=linux.git sched_ext: Add an event, SCX_EV_DISPATCH_KEEP_LAST Add a core event, SCX_EV_DISPATCH_KEEP_LAST, which represents how many times a task is continued to run without ops.enqueue() when SCX_OPS_ENQ_LAST is not set. __scx_add_event() is used since the caller holds an rq lock, so the preemption has already been disabled. Signed-off-by: Changwoo Min Signed-off-by: Tejun Heo --- diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index d1447f18381e..cbb3d059072f 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -1455,6 +1455,12 @@ struct scx_event_stats { * the meantime. In this case, the task is bounced to the global DSQ. */ u64 SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE; + + /* + * If SCX_OPS_ENQ_LAST is not set, the number of times that a task + * continued to run because there were no other tasks on the CPU. + */ + u64 SCX_EV_DISPATCH_KEEP_LAST; }; /* @@ -2907,6 +2913,7 @@ no_tasks: if (prev_on_rq && (!static_branch_unlikely(&scx_ops_enq_last) || scx_rq_bypassing(rq))) { rq->scx.flags |= SCX_RQ_BAL_KEEP; + __scx_add_event(SCX_EV_DISPATCH_KEEP_LAST, 1); goto has_tasks; } rq->scx.flags &= ~SCX_RQ_IN_BALANCE; @@ -4977,6 +4984,7 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len) scx_bpf_events(&events, sizeof(events)); scx_dump_event(s, &events, SCX_EV_SELECT_CPU_FALLBACK); scx_dump_event(s, &events, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE); + scx_dump_event(s, &events, SCX_EV_DISPATCH_KEEP_LAST); if (seq_buf_has_overflowed(&s) && dump_len >= sizeof(trunc_marker)) memcpy(ei->dump + dump_len - sizeof(trunc_marker), @@ -7112,6 +7120,7 @@ __bpf_kfunc void scx_bpf_events(struct scx_event_stats *events, e_cpu = per_cpu_ptr(&event_stats_cpu, cpu); scx_agg_event(&e_sys, e_cpu, SCX_EV_SELECT_CPU_FALLBACK); scx_agg_event(&e_sys, e_cpu, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE); + scx_agg_event(&e_sys, e_cpu, SCX_EV_DISPATCH_KEEP_LAST); } /*