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Subject[PATCH tip/core/rcu 20/55] rcu: Add event-trace markers to TREE_RCU kthreads
Date
From: Paul E. McKenney <paul.mckenney@linaro.org>

Add event-trace markers to TREE_RCU kthreads to allow including these
kthread's CPU time in the utilization calculations.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/trace/events/rcu.h | 3 +++
kernel/rcutree_plugin.h | 12 ++++++++++++
2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 508824e5..ac52aba 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -13,6 +13,9 @@
* "Start <activity>" -- Mark the start of the specified activity,
* such as "context switch". Nesting is permitted.
* "End <activity>" -- Mark the end of the specified activity.
+ *
+ * An "@" character within "<activity>" is a comment character: Data
+ * reduction scripts will ignore the "@" and the remainder of the line.
*/
TRACE_EVENT(rcu_utilization,

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index ecd48a2..94d9ca1 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1219,9 +1219,12 @@ static int rcu_boost_kthread(void *arg)
int spincnt = 0;
int more2boost;

+ trace_rcu_utilization("Start boost kthread@init");
for (;;) {
rnp->boost_kthread_status = RCU_KTHREAD_WAITING;
+ trace_rcu_utilization("End boost kthread@rcu_wait");
rcu_wait(rnp->boost_tasks || rnp->exp_tasks);
+ trace_rcu_utilization("Start boost kthread@rcu_wait");
rnp->boost_kthread_status = RCU_KTHREAD_RUNNING;
more2boost = rcu_boost(rnp);
if (more2boost)
@@ -1229,11 +1232,14 @@ static int rcu_boost_kthread(void *arg)
else
spincnt = 0;
if (spincnt > 10) {
+ trace_rcu_utilization("End boost kthread@rcu_yield");
rcu_yield(rcu_boost_kthread_timer, (unsigned long)rnp);
+ trace_rcu_utilization("Start boost kthread@rcu_yield");
spincnt = 0;
}
}
/* NOTREACHED */
+ trace_rcu_utilization("End boost kthread@notreached");
return 0;
}

@@ -1490,9 +1496,12 @@ static int rcu_cpu_kthread(void *arg)
char work;
char *workp = &per_cpu(rcu_cpu_has_work, cpu);

+ trace_rcu_utilization("Start CPU kthread@init");
for (;;) {
*statusp = RCU_KTHREAD_WAITING;
+ trace_rcu_utilization("End CPU kthread@rcu_wait");
rcu_wait(*workp != 0 || kthread_should_stop());
+ trace_rcu_utilization("Start CPU kthread@rcu_wait");
local_bh_disable();
if (rcu_cpu_kthread_should_stop(cpu)) {
local_bh_enable();
@@ -1513,11 +1522,14 @@ static int rcu_cpu_kthread(void *arg)
spincnt = 0;
if (spincnt > 10) {
*statusp = RCU_KTHREAD_YIELDING;
+ trace_rcu_utilization("End CPU kthread@rcu_yield");
rcu_yield(rcu_cpu_kthread_timer, (unsigned long)cpu);
+ trace_rcu_utilization("Start CPU kthread@rcu_yield");
spincnt = 0;
}
}
*statusp = RCU_KTHREAD_STOPPED;
+ trace_rcu_utilization("End CPU kthread@term");
return 0;
}

--
1.7.3.2


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