waketorture: Add utilization measurement

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/waketorture.c b/kernel/rcu/waketorture.c
index 75bc547206cc2599c949e22365bf7bcb78b83f91..3068a5c858c8d6e5ff0429ece89aa9727f09adfd 100644 (file)
--- a/kernel/rcu/waketorture.c
+++ b/kernel/rcu/waketorture.c
@@ -81,7 +81,9 @@ static unsigned long *waiter_iter;    /* Number of wait iterations. */
 static bool *waiter_cts;               /* Waiter already checked. */
 static unsigned long *waiter_kicks;    /* Number of waiter starvations. */
 static unsigned long *waiter_ts;       /* Jiffies last run. */
-DEFINE_MUTEX(waiter_mutex);
+static DEFINE_MUTEX(waiter_mutex);
+static DEFINE_PER_CPU(u64, waiter_cputime); /* Nanoseconds. */
+static u64 starttime;
 
 static int torture_runnable = IS_ENABLED(MODULE);
 module_param(torture_runnable, int, 0444);
@@ -133,16 +135,23 @@ static int wake_torture_waiter(void *arg)
 {
        int i;
        long me = (long)arg;
+       u64 ts;
 
        VERBOSE_TOROUT_STRING("wake_torture_waiter task started");
        set_user_nice(current, MAX_NICE);
 
+       preempt_disable();
+       ts = trace_clock_local();
        do {
                waiter_ts[me] = jiffies;
                smp_mb(); /* Ensure waiter_ts[] written before waiter_cts[]. */
                          /* Pairs with [A]. */
                waiter_cts[me] = false;
+               __this_cpu_add(waiter_cputime, trace_clock_local() - ts);
+               preempt_enable();
                cur_ops->wait(wait_duration);
+               preempt_disable();
+               ts = trace_clock_local();
                waiter_iter[me]++;
                for (i = 0; i < nrealwaiters; i++) {
                        if (waiter_done[i] ||
@@ -164,8 +173,14 @@ static int wake_torture_waiter(void *arg)
                                mutex_unlock(&waiter_mutex);
                        }
                }
+               __this_cpu_add(waiter_cputime, trace_clock_local() - ts);
+               preempt_enable();
                torture_shutdown_absorb("wake_torture_waiter");
+               preempt_disable();
+               ts = trace_clock_local();
        } while (!torture_must_stop());
+       __this_cpu_add(waiter_cputime, trace_clock_local() - ts);
+       preempt_enable();
        mutex_lock(&waiter_mutex);
        waiter_done[me] = true;
        mutex_unlock(&waiter_mutex);
@@ -189,6 +204,8 @@ wake_torture_stats_print(void)
 {
        int i;
        bool tardy = false;
+       u64 timediff;
+       u64 timetot;
 
        if (!waiter_done || !waiter_iter || !waiter_cts ||
            !waiter_kicks || !waiter_ts) {
@@ -212,6 +229,15 @@ wake_torture_stats_print(void)
                pr_cont("\n");
        else
                TOROUT_STRING(" No tardy kthreads");
+       timediff = (trace_clock_global() - starttime) / 1000;
+       timetot = 0;
+       for_each_possible_cpu(i)
+               timetot += READ_ONCE(per_cpu(waiter_cputime, i));
+       timetot /= nr_cpu_ids;
+       timetot /= timediff;
+       pr_alert("%s" TORTURE_FLAG " timediff: %llu utilization: %llu.%llu nr_cpu_ids: %d\n",
+                torture_type, timediff,
+                timetot / 1000ULL, timetot % 1000ULL, nr_cpu_ids);
 }
 
 /*
@@ -290,6 +316,7 @@ wake_torture_init(void)
 
        if (!torture_init_begin(torture_type, verbose, &torture_runnable))
                return -EBUSY;
+       starttime = trace_clock_global();
 
        /* Process args and tell the world that the torturer is on the job. */
        for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index b84b33422fe9eada3f26d7dc285a5facdd6c6a80..f17463f4a8f4f1adee7a0d01ef694e5f9e2c72ee 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1417,6 +1417,7 @@ config WAKE_TORTURE_TEST
        tristate "Torture test for wakeups and CPU hotplug"
        depends on DEBUG_KERNEL
        depends on 64BIT
+       depends on TRACE_CLOCK
        select TORTURE_TEST
        default n
        help