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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-07-23 12:05:55 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-09-23 07:42:22 -0700
commit13dbf9140c726c307a9c7e2b7ff83cf95da3bb44 (patch)
treec74294271b88bb0a99f841c214c0f10b8b6ab449
parentab840f7a06df780c4db01f34a5660b1e472d9ca6 (diff)
downloadlinux-linaro-stable-13dbf9140c726c307a9c7e2b7ff83cf95da3bb44.tar.gz
rcu: Track CPU-hotplug duration statistics
Many rcutorture runs include CPU-hotplug operations in their stress testing. This commit accumulates statistics on the durations of these operations in deference to the recent concern about the overhead and latency of these operations. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
-rw-r--r--kernel/rcutorture.c42
1 files changed, 37 insertions, 5 deletions
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 53c548c39265..2736cc878ba2 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -177,8 +177,14 @@ static long n_rcu_torture_boosts;
static long n_rcu_torture_timers;
static long n_offline_attempts;
static long n_offline_successes;
+static unsigned long sum_offline;
+static int min_offline = -1;
+static int max_offline;
static long n_online_attempts;
static long n_online_successes;
+static unsigned long sum_online;
+static int min_online = -1;
+static int max_online;
static long n_barrier_attempts;
static long n_barrier_successes;
static struct list_head rcu_torture_removed;
@@ -1215,11 +1221,13 @@ rcu_torture_printk(char *page)
n_rcu_torture_boost_failure,
n_rcu_torture_boosts,
n_rcu_torture_timers);
- cnt += sprintf(&page[cnt], "onoff: %ld/%ld:%ld/%ld ",
- n_online_successes,
- n_online_attempts,
- n_offline_successes,
- n_offline_attempts);
+ cnt += sprintf(&page[cnt],
+ "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
+ n_online_successes, n_online_attempts,
+ n_offline_successes, n_offline_attempts,
+ min_online, max_online,
+ min_offline, max_offline,
+ sum_online, sum_offline, HZ);
cnt += sprintf(&page[cnt], "barrier: %ld/%ld:%ld",
n_barrier_successes,
n_barrier_attempts,
@@ -1491,8 +1499,10 @@ static int __cpuinit
rcu_torture_onoff(void *arg)
{
int cpu;
+ unsigned long delta;
int maxcpu = -1;
DEFINE_RCU_RANDOM(rand);
+ unsigned long starttime;
VERBOSE_PRINTK_STRING("rcu_torture_onoff task started");
for_each_online_cpu(cpu)
@@ -1510,6 +1520,7 @@ rcu_torture_onoff(void *arg)
printk(KERN_ALERT "%s" TORTURE_FLAG
"rcu_torture_onoff task: offlining %d\n",
torture_type, cpu);
+ starttime = jiffies;
n_offline_attempts++;
if (cpu_down(cpu) == 0) {
if (verbose)
@@ -1517,12 +1528,23 @@ rcu_torture_onoff(void *arg)
"rcu_torture_onoff task: offlined %d\n",
torture_type, cpu);
n_offline_successes++;
+ delta = jiffies - starttime;
+ sum_offline += delta;
+ if (min_offline < 0) {
+ min_offline = delta;
+ max_offline = delta;
+ }
+ if (min_offline > delta)
+ min_offline = delta;
+ if (max_offline < delta)
+ max_offline = delta;
}
} else if (cpu_is_hotpluggable(cpu)) {
if (verbose)
printk(KERN_ALERT "%s" TORTURE_FLAG
"rcu_torture_onoff task: onlining %d\n",
torture_type, cpu);
+ starttime = jiffies;
n_online_attempts++;
if (cpu_up(cpu) == 0) {
if (verbose)
@@ -1530,6 +1552,16 @@ rcu_torture_onoff(void *arg)
"rcu_torture_onoff task: onlined %d\n",
torture_type, cpu);
n_online_successes++;
+ delta = jiffies - starttime;
+ sum_online += delta;
+ if (min_online < 0) {
+ min_online = delta;
+ max_online = delta;
+ }
+ if (min_online > delta)
+ min_online = delta;
+ if (max_online < delta)
+ max_online = delta;
}
}
schedule_timeout_interruptible(onoff_interval * HZ);