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authorDaniel Bristot de Oliveira <bristot@kernel.org>2022-02-18 16:17:38 +0100
committerSteven Rostedt (Google) <rostedt@goodmis.org>2022-02-25 12:07:01 -0500
commitdd990352f01ee9a6c6eee152e5d11c021caccfe4 (patch)
tree84fff9fc4945fc10a63db9d7d1f56bd6b00dd7ac /kernel
parentab2f993c01f261aa3eeb8842842ff38bff7806b6 (diff)
downloadlinux-dd990352f01ee9a6c6eee152e5d11c021caccfe4.tar.bz2
tracing/osnoise: Make osnoise_main to sleep for microseconds
osnoise's runtime and period are in the microseconds scale, but it is currently sleeping in the millisecond's scale. This behavior roots in the usage of hwlat as the skeleton for osnoise. Make osnoise to sleep in the microseconds scale. Also, move the sleep to a specialized function. Link: https://lkml.kernel.org/r/302aa6c7bdf2d131719b22901905e9da122a11b2.1645197336.git.bristot@kernel.org Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_osnoise.c53
1 files changed, 32 insertions, 21 deletions
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 870a08da5b48..cfddb30e65ab 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -1437,6 +1437,37 @@ static struct cpumask osnoise_cpumask;
static struct cpumask save_cpumask;
/*
+ * osnoise_sleep - sleep until the next period
+ */
+static void osnoise_sleep(void)
+{
+ u64 interval;
+ ktime_t wake_time;
+
+ mutex_lock(&interface_lock);
+ interval = osnoise_data.sample_period - osnoise_data.sample_runtime;
+ mutex_unlock(&interface_lock);
+
+ /*
+ * differently from hwlat_detector, the osnoise tracer can run
+ * without a pause because preemption is on.
+ */
+ if (!interval) {
+ /* Let synchronize_rcu_tasks() make progress */
+ cond_resched_tasks_rcu_qs();
+ return;
+ }
+
+ wake_time = ktime_add_us(ktime_get(), interval);
+ __set_current_state(TASK_INTERRUPTIBLE);
+
+ while (schedule_hrtimeout_range(&wake_time, 0, HRTIMER_MODE_ABS)) {
+ if (kthread_should_stop())
+ break;
+ }
+}
+
+/*
* osnoise_main - The osnoise detection kernel thread
*
* Calls run_osnoise() function to measure the osnoise for the configured runtime,
@@ -1444,30 +1475,10 @@ static struct cpumask save_cpumask;
*/
static int osnoise_main(void *data)
{
- u64 interval;
while (!kthread_should_stop()) {
-
run_osnoise();
-
- mutex_lock(&interface_lock);
- interval = osnoise_data.sample_period - osnoise_data.sample_runtime;
- mutex_unlock(&interface_lock);
-
- do_div(interval, USEC_PER_MSEC);
-
- /*
- * differently from hwlat_detector, the osnoise tracer can run
- * without a pause because preemption is on.
- */
- if (interval < 1) {
- /* Let synchronize_rcu_tasks() make progress */
- cond_resched_tasks_rcu_qs();
- continue;
- }
-
- if (msleep_interruptible(interval))
- break;
+ osnoise_sleep();
}
return 0;