sched_ext: Add an event, SCX_EV_BYPASS_DURATION

Add a core event, SCX_EV_BYPASS_DURATION, which represents the
total duration of bypass modes in nanoseconds.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 0ed2db44ae335fd5ff10335e5efec373958176e1..8a9a30895381ac8536185a2d8242f88d78c0e79b 100644 (file)
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -1468,6 +1468,11 @@ struct scx_event_stats {
         */
        u64             SCX_EV_ENQ_SKIP_EXITING;
 
+       /*
+        * The total duration of bypass modes in nanoseconds.
+        */
+       u64             SCX_EV_BYPASS_DURATION;
+
        /*
         * The number of tasks dispatched in the bypassing mode.
         */
@@ -4408,6 +4413,8 @@ static void scx_clear_softlockup(void)
 static void scx_ops_bypass(bool bypass)
 {
        static DEFINE_RAW_SPINLOCK(bypass_lock);
+       static unsigned long bypass_timestamp;
+
        int cpu;
        unsigned long flags;
 
@@ -4417,12 +4424,15 @@ static void scx_ops_bypass(bool bypass)
                WARN_ON_ONCE(scx_ops_bypass_depth <= 0);
                if (scx_ops_bypass_depth != 1)
                        goto unlock;
+               bypass_timestamp = ktime_get_ns();
                scx_add_event(SCX_EV_BYPASS_ACTIVATE, 1);
        } else {
                scx_ops_bypass_depth--;
                WARN_ON_ONCE(scx_ops_bypass_depth < 0);
                if (scx_ops_bypass_depth != 0)
                        goto unlock;
+               scx_add_event(SCX_EV_BYPASS_DURATION,
+                             ktime_get_ns() - bypass_timestamp);
        }
 
        atomic_inc(&scx_ops_breather_depth);
@@ -5013,6 +5023,7 @@ static void scx_dump_state(struct scx_exit_info *ei, size_t dump_len)
        scx_dump_event(s, &events, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE);
        scx_dump_event(s, &events, SCX_EV_DISPATCH_KEEP_LAST);
        scx_dump_event(s, &events, SCX_EV_ENQ_SKIP_EXITING);
+       scx_dump_event(s, &events, SCX_EV_BYPASS_DURATION);
        scx_dump_event(s, &events, SCX_EV_BYPASS_DISPATCH);
        scx_dump_event(s, &events, SCX_EV_BYPASS_ACTIVATE);
 
@@ -7152,6 +7163,7 @@ __bpf_kfunc void scx_bpf_events(struct scx_event_stats *events,
                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);
                scx_agg_event(&e_sys, e_cpu, SCX_EV_ENQ_SKIP_EXITING);
+               scx_agg_event(&e_sys, e_cpu, SCX_EV_BYPASS_DURATION);
                scx_agg_event(&e_sys, e_cpu, SCX_EV_BYPASS_DISPATCH);
                scx_agg_event(&e_sys, e_cpu, SCX_EV_BYPASS_ACTIVATE);
        }