Re: [PATCH v2] PM / Domains: enable domain idle state accounting

[Lina Iyer <ilina@codeaurora.org>]

On Mon, Oct 05 2020 at 07:27 -0600, Rafael J. Wysocki wrote:
>On Sat, Oct 3, 2020 at 5:56 PM Lina Iyer <ilina@codeaurora.org> wrote:
>>
>> To enable better debug of PM domains, let's keep a track of the success
>> and rejections in entering each domain idle state.
>>
>> This statistics is exported in debugfs when reading the idle_states
>> node, associated with each PM domain.
>>
>> Signed-off-by: Lina Iyer <ilina@codeaurora.org>
>> ---
>> Changes in v2:
>>         - Renamed 'failed' to 'rejected'
>>
>> This patch depends-on: https://lkml.org/lkml/2020/9/24/465
>> ---
>>  drivers/base/power/domain.c | 7 +++++--
>>  include/linux/pm_domain.h   | 2 ++
>>  2 files changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index f001ac6326fb..dbe89454f594 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -564,6 +564,7 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
>>
>>         genpd->status = GENPD_STATE_OFF;
>>         genpd_update_accounting(genpd);
>> +       genpd->states[genpd->state_idx].usage++;
>
>Why not to do this in genpd_update_accounting()?
>
That function is clubbed with debugfs and does heavy tracking using
timers. This accounting is fairly basic and still quite useful for
debugging.

>>
>>         list_for_each_entry(link, &genpd->child_links, child_node) {
>>                 genpd_sd_counter_dec(link->parent);
>> @@ -574,6 +575,7 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
>>
>>         return 0;
>>  busy:
>> +       genpd->states[genpd->state_idx].rejected++;
>>         if (nr_calls)
>>                 __raw_notifier_call_chain(&genpd->power_notifiers,
>>                                           GENPD_STATE_ON, NULL,
>
>This doesn't apply to the current code, please rebase.
>
I believe it applies cleanly on top of
https://lkml.org/lkml/2020/9/24/465, which I believe you are applied to
your tree. Let me rebase and re-post. Sorry about that.

Thanks,
Lina

>> @@ -3053,7 +3055,7 @@ static int idle_states_show(struct seq_file *s, void *data)
>>         if (ret)
>>                 return -ERESTARTSYS;
>>
>> -       seq_puts(s, "State          Time Spent(ms)\n");
>> +       seq_puts(s, "State          Time Spent(ms) Usage          Rejected\n");
>>
>>         for (i = 0; i < genpd->state_count; i++) {
>>                 ktime_t delta = 0;
>> @@ -3065,7 +3067,8 @@ static int idle_states_show(struct seq_file *s, void *data)
>>
>>                 msecs = ktime_to_ms(
>>                         ktime_add(genpd->states[i].idle_time, delta));
>> -               seq_printf(s, "S%-13i %lld\n", i, msecs);
>> +               seq_printf(s, "S%-13i %-14lld %-14llu %llu\n", i, msecs,
>> +                             genpd->states[i].usage, genpd->states[i].rejected);
>>         }
>>
>>         genpd_unlock(genpd);
>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>> index 3b2b561ce846..239647f2d27f 100644
>> --- a/include/linux/pm_domain.h
>> +++ b/include/linux/pm_domain.h
>> @@ -82,6 +82,8 @@ struct genpd_power_state {
>>         s64 power_off_latency_ns;
>>         s64 power_on_latency_ns;
>>         s64 residency_ns;
>> +       u64 usage;
>> +       u64 rejected;
>>         struct fwnode_handle *fwnode;
>>         ktime_t idle_time;
>>         void *data;
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>> a Linux Foundation Collaborative Project
>>