Hi Rafael,

On 6/20/23 18:40, Rafael J. Wysocki wrote:

On Mon, May 22, 2023 at 4:57 PM Lukasz Luba [off-list ref] wrote:

quoted

Some of the frequency update requests coming form the task scheduler
might be filter out. It can happen when the previous request was served
not that long ago (in a period smaller than provided by the cpufreq driver
as minimum for frequency update). In such case, we want to know if some of
the frequency updates cannot make through.
Export the new tracepoint as well. That would allow to handle it by a
toolkit for trace analyzes.

Reported-by: kernel test robot <redacted> # solved tricky build
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
---
  include/trace/events/sched.h     |  4 ++++
  kernel/sched/cpufreq_schedutil.c | 10 ++++++++--
  2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index dbfb30809f15..e34b7cd5de73 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h

@@ -739,6 +739,10 @@ DECLARE_TRACE(uclamp_update_tsk_tp,
         TP_PROTO(struct task_struct *tsk, int uclamp_id,  unsigned int value),
         TP_ARGS(tsk, uclamp_id, value));

+DECLARE_TRACE(schedutil_update_filtered_tp,
+       TP_PROTO(int cpu),
+       TP_ARGS(cpu));
+
  #endif /* _TRACE_SCHED_H */

  /* This part must be outside protection */

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index f462496e5c07..4f9daf258a65 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c

@@ -6,6 +6,8 @@
   * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
   */

+EXPORT_TRACEPOINT_SYMBOL_GPL(schedutil_update_filtered_tp);
+
  #define IOWAIT_BOOST_MIN       (SCHED_CAPACITY_SCALE / 8)

  struct sugov_tunables {

@@ -318,8 +320,10 @@ static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,

         ignore_dl_rate_limit(sg_cpu);

-       if (!sugov_should_update_freq(sg_cpu->sg_policy, time))
+       if (!sugov_should_update_freq(sg_cpu->sg_policy, time)) {
+               trace_schedutil_update_filtered_tp(sg_cpu->cpu);

It looks like the tracepoint can be added to
sugov_should_update_freq() for less code duplication.

Make sense. I will move that trace there.

In such case, of movement that trace call...
Based on your comment for patch 2/3 I got impression
that you still want it. For me it looks more 'aligned' w/ that
patch 2/3. The two functions code flows:
sugov_update_shared() and sugov_update_single_common() - how
they call and interpret result from
sugov_should_update_freq() - is more clear IMO.

So I will keep that patch 2/3 in the next version. Although,
if you don't like it - please tell me and I will drop it.

Thanks for the review!

Lukasz