This commit adds a guest_os_delay module parameter that extends warm-up
and cool-down the specified number of seconds before and after the series
of test runs. This allows the data-collection intervals from any given
rcuscale guest OSes to line up with active periods in the other rcuscale
guest OSes, and also allows the thermal warm-up period required to obtain
consistent results from one test to the next.
Signed-off-by: Paul E. McKenney <paul...@kernel.org>
---
kernel/rcu/refscale.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index af32331ef645a..be66e5a67ee19 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -76,6 +76,9 @@ MODULE_PARM_DESC(scale_type, "Type of test (rcu, srcu,
refcnt, rwsem, rwlock.");
torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
torture_param(int, verbose_batched, 0, "Batch verbose debugging printk()s");
+// Number of seconds to extend warm-up and cool-down for multiple guest OSes
+torture_param(long, guest_os_delay, 0,
+ "Number of seconds to extend warm-up/cool-down for multiple guest
OSes.");
// Wait until there are multiple CPUs before starting test.
torture_param(int, holdoff, IS_BUILTIN(CONFIG_RCU_REF_SCALE_TEST) ? 10 : 0,
"Holdoff time before test start (s)");
@@ -835,6 +838,18 @@ static void rcu_scale_one_reader(void)
cur_ops->delaysection(loops, readdelay / 1000, readdelay %
1000);
}
+// Warm up cache, or, if needed run a series of rcu_scale_one_reader()
+// to allow multiple rcuscale guest OSes to collect mutually valid data.
+static void rcu_scale_warm_cool(void)
+{
+ unsigned long jdone = jiffies + (guest_os_delay > 0 ? guest_os_delay *
HZ : -1);
+
+ do {
+ rcu_scale_one_reader();
+ cond_resched();
+ } while (time_before(jiffies, jdone));
+}
+
// Reader kthread. Repeatedly does empty RCU read-side
// critical section, minimizing update-side interference.
static int
@@ -991,6 +1006,7 @@ static int main_func(void *arg)
schedule_timeout_uninterruptible(1);
// Start exp readers up per experiment
+ rcu_scale_warm_cool();
for (exp = 0; exp < nruns && !torture_must_stop(); exp++) {
if (torture_must_stop())
goto end;
@@ -1021,6 +1037,7 @@ static int main_func(void *arg)
result_avg[exp] = div_u64(1000 * process_durations(nreaders),
nreaders * loops);
}
+ rcu_scale_warm_cool();
// Print the average of all experiments
SCALEOUT("END OF TEST. Calculating average duration per loop
(nanoseconds)...\n");
--
2.40.1
