commit eba1ed4b7e52720e3099325874811c38a5ec1562
author Ingo Molnar <mingo@elte.hu> Mon Oct 15 17:00:02 2007 +0200
committer Ingo Molnar <mingo@elte.hu> Mon Oct 15 17:00:02 2007 +0200
tree 4ce145dd10b6cc248a2bc3463822dff23f9dd3c5
parent a4b29ba2f72673aaa60ba11ced74d579771dd578

sched: debug: track maximum 'slice'

track the maximum amount of time a task has executed while
the CPU load was at least 2x. (i.e. at least two nice-0
tasks were runnable)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/sched.h

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 833f7dc..9761b16 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -921,6 +921,7 @@
 	u64			block_start;
 	u64			block_max;
 	u64			exec_max;
+	u64			slice_max;
 
 	unsigned long		wait_runtime_overruns;
 	unsigned long		wait_runtime_underruns;

kernel/sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index e92b185..282d037 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1603,6 +1603,7 @@
 	p->se.sleep_max			= 0;
 	p->se.block_max			= 0;
 	p->se.exec_max			= 0;
+	p->se.slice_max			= 0;
 	p->se.wait_max			= 0;
 	p->se.wait_runtime_overruns	= 0;
 	p->se.wait_runtime_underruns	= 0;

kernel/sched_debug.c

diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 94915f1..fd080f6 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -254,6 +254,7 @@
 	P(se.sleep_max);
 	P(se.block_max);
 	P(se.exec_max);
+	P(se.slice_max);
 	P(se.wait_max);
 	P(se.wait_runtime_overruns);
 	P(se.wait_runtime_underruns);
@@ -282,6 +283,7 @@
 	p->se.sleep_max			= 0;
 	p->se.block_max			= 0;
 	p->se.exec_max			= 0;
+	p->se.slice_max			= 0;
 	p->se.wait_max			= 0;
 	p->se.wait_runtime_overruns	= 0;
 	p->se.wait_runtime_underruns	= 0;

kernel/sched_fair.c

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 0990b20..5c15d8a 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -739,6 +739,17 @@
 	update_stats_wait_end(cfs_rq, se);
 	update_stats_curr_start(cfs_rq, se);
 	set_cfs_rq_curr(cfs_rq, se);
+#ifdef CONFIG_SCHEDSTATS
+	/*
+	 * Track our maximum slice length, if the CPU's load is at
+	 * least twice that of our own weight (i.e. dont track it
+	 * when there are only lesser-weight tasks around):
+	 */
+	if (rq_of(cfs_rq)->ls.load.weight >= 2*se->load.weight) {
+		se->slice_max = max(se->slice_max,
+			se->sum_exec_runtime - se->prev_sum_exec_runtime);
+	}
+#endif
 	se->prev_sum_exec_runtime = se->sum_exec_runtime;
 }