ANDROID: sched/events: Introduce sched_entity load tracking trace event

The trace event keys load and util (utilization) are mapped to:

 (1) load : se->avg.load_avg

 (2) util : se->avg.util_avg

To let this trace event work for configurations w/ and w/o group
scheduling support for cfs (CONFIG_FAIR_GROUP_SCHED) the following
special handling is necessary for non-existent key=value pairs:

 path = "(null)" : In case of !CONFIG_FAIR_GROUP_SCHED or the
                   sched_entity represents a task.

 comm = "(null)" : In case sched_entity represents a task_group.

 pid = -1        : In case sched_entity represents a task_group.

The following list shows examples of the key=value pairs in different
configurations for:

 (1) a task:

     cpu=0 path=(null) comm=sshd pid=2206 load=102 util=102

 (2) a taskgroup:

     cpu=1 path=/tg1/tg11/tg111 comm=(null) pid=-1 load=882 util=510

 (3) an autogroup:

     cpu=0 path=/autogroup-13 comm=(null) pid=-1 load=49 util=48

 (4) w/o CONFIG_FAIR_GROUP_SCHED:

     cpu=0 path=(null) comm=sshd pid=2211 load=301 util=265

The trace event is only defined for CONFIG_SMP.

The helper functions __trace_sched_cpu(), __trace_sched_path() and
__trace_sched_id() are extended to deal with sched_entities as well.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Change-Id: Ia628795d7f0fd54e22a1daeb6e3d37b30ab85583
Signed-off-by: Chris Redpath <chris.redpath@arm.com>

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 96ea879b2014fec2128f47149eeb881def42170c..5e1c9314c0809f9ed7e13a105073c1eee8b50a90 100644 (file)
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -574,14 +574,15 @@ TRACE_EVENT(sched_wake_idle_without_ipi,
 #ifdef CONFIG_SMP
 #ifdef CREATE_TRACE_POINTS
 static inline
-int __trace_sched_cpu(struct cfs_rq *cfs_rq)
+int __trace_sched_cpu(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 #ifdef CONFIG_FAIR_GROUP_SCHED
-       struct rq *rq = cfs_rq->rq;
+       struct rq *rq = cfs_rq ? cfs_rq->rq : NULL;
 #else
-       struct rq *rq = container_of(cfs_rq, struct rq, cfs);
+       struct rq *rq = cfs_rq ? container_of(cfs_rq, struct rq, cfs) : NULL;
 #endif
-       return cpu_of(rq);
+       return rq ? cpu_of(rq)
+                 : task_cpu((container_of(se, struct task_struct, se)));
 }
 
 static inline
@@ -590,18 +591,26 @@ int __trace_sched_path(struct cfs_rq *cfs_rq, char *path, int len)
 #ifdef CONFIG_FAIR_GROUP_SCHED
        int l = path ? len : 0;
 
-       if (task_group_is_autogroup(cfs_rq->tg))
+       if (cfs_rq && task_group_is_autogroup(cfs_rq->tg))
                return autogroup_path(cfs_rq->tg, path, l) + 1;
-       else
+       else if (cfs_rq && cfs_rq->tg->css.cgroup)
                return cgroup_path(cfs_rq->tg->css.cgroup, path, l) + 1;
-#else
+#endif
        if (path)
                strcpy(path, "(null)");
 
        return strlen("(null)");
-#endif
 }
 
+static inline
+struct cfs_rq *__trace_sched_group_cfs_rq(struct sched_entity *se)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+       return se->my_q;
+#else
+       return NULL;
+#endif
+}
 #endif /* CREATE_TRACE_POINTS */
 
 /*
@@ -622,7 +631,7 @@ TRACE_EVENT(sched_load_cfs_rq,
        ),
 
        TP_fast_assign(
-               __entry->cpu    = __trace_sched_cpu(cfs_rq);
+               __entry->cpu    = __trace_sched_cpu(cfs_rq, NULL);
                __trace_sched_path(cfs_rq, __get_dynamic_array(path),
                                   __get_dynamic_array_len(path));
                __entry->load   = cfs_rq->runnable_load_avg;
@@ -632,6 +641,44 @@ TRACE_EVENT(sched_load_cfs_rq,
        TP_printk("cpu=%d path=%s load=%lu util=%lu", __entry->cpu,
                  __get_str(path), __entry->load, __entry->util)
 );
+
+/*
+ * Tracepoint for sched_entity load tracking:
+ */
+TRACE_EVENT(sched_load_se,
+
+       TP_PROTO(struct sched_entity *se),
+
+       TP_ARGS(se),
+
+       TP_STRUCT__entry(
+               __field(        int,            cpu                           )
+               __dynamic_array(char,           path,
+                 __trace_sched_path(__trace_sched_group_cfs_rq(se), NULL, 0) )
+               __array(        char,           comm,   TASK_COMM_LEN         )
+               __field(        pid_t,          pid                           )
+               __field(        unsigned long,  load                          )
+               __field(        unsigned long,  util                          )
+       ),
+
+       TP_fast_assign(
+               struct cfs_rq *gcfs_rq = __trace_sched_group_cfs_rq(se);
+               struct task_struct *p = gcfs_rq ? NULL
+                                   : container_of(se, struct task_struct, se);
+
+               __entry->cpu = __trace_sched_cpu(gcfs_rq, se);
+               __trace_sched_path(gcfs_rq, __get_dynamic_array(path),
+                                  __get_dynamic_array_len(path));
+               memcpy(__entry->comm, p ? p->comm : "(null)", TASK_COMM_LEN);
+               __entry->pid = p ? p->pid : -1;
+               __entry->load = se->avg.load_avg;
+               __entry->util = se->avg.util_avg;
+       ),
+
+       TP_printk("cpu=%d path=%s comm=%s pid=%d load=%lu util=%lu",
+                 __entry->cpu, __get_str(path), __entry->comm,
+                 __entry->pid, __entry->load, __entry->util)
+);
 #endif /* CONFIG_SMP */
 #endif /* _TRACE_SCHED_H */
 

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 733e7ee870adb39696a491c3db3c8a9a326103df..cfd646048725407c239b8663075f8f6f0487b4a0 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3025,6 +3025,8 @@ ___update_load_avg(u64 now, int cpu, struct sched_avg *sa,
 
        if (cfs_rq)
                trace_sched_load_cfs_rq(cfs_rq);
+       else
+               trace_sched_load_se(container_of(sa, struct sched_entity, avg));
 
        return 1;
 }
@@ -3270,6 +3272,7 @@ static inline int propagate_entity_load_avg(struct sched_entity *se)
        update_tg_cfs_load(cfs_rq, se);
 
        trace_sched_load_cfs_rq(cfs_rq);
+       trace_sched_load_se(se);
 
        return 1;
 }