Re: [PATCH v4 18/24] PM / devfreq: tegra30: Optimize CPUFreq notifier

Chanwoo Choi
2019-07-19T01:09:57Z

On 19. 7. 19. 오전 9:42, Dmitry Osipenko wrote:
> В Thu, 18 Jul 2019 18:48:42 +0900
> Chanwoo Choi <cw00.choi@samsung.com> пишет:
>
>> On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
>>> When CPU's memory activity is low or memory activity is high such
>>> that CPU's frequency contribution to the boosting is not taken into
>>> account, then there is no need to schedule devfreq's update. This
>>> eliminates unnecessary CPU activity during of idling caused by the
>>> scheduled work.
>>>
>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>>> ---
>>> drivers/devfreq/tegra30-devfreq.c | 73
>>> +++++++++++++++++++++++++++---- 1 file changed, 64 insertions(+), 9
>>> deletions(-)
>>
>> Patch4 add the 'cpufreq notifier' and this patch optimize the cpufreq
>> notifier. I think t hat you can combine two patches.
>
> I'd prefer to keep them separate for a sake of git bisection.

Sorry, patch7 instead of patch4.

Patch7 made the 'tegra_actmon_cpu_notify_cb()' function
and this patch makes 'tegra_actmon_cpufreq_contribution' function
which is only called in the 'tegra_actmon_cpu_notify_cb()' function.

It is enough to make them as the only one patch related to
the cpu notifier. As I replied on patch17, you can merge
the patch if the patches has some relationship in this patchset.

>
>>>
>>> diff --git a/drivers/devfreq/tegra30-devfreq.c
>>> b/drivers/devfreq/tegra30-devfreq.c index
>>> 43c9c5fbfe91..8d6bf6e9f1ae 100644 ---
>>> a/drivers/devfreq/tegra30-devfreq.c +++
>>> b/drivers/devfreq/tegra30-devfreq.c @@ -216,10 +216,10 @@ static
>>> inline unsigned long do_percent(unsigned long val, unsigned int
>>> pct) return val * pct / 100; }
>>>
>>> -static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq
>>> *tegra) +static unsigned long actmon_cpu_to_emc_rate(struct
>>> tegra_devfreq *tegra,
>>> + unsigned int cpu_freq)
>>> {
>>> const struct tegra_actmon_emc_ratio *ratio =
>>> actmon_emc_ratios;
>>> - unsigned int cpu_freq = cpufreq_get(0);
>>> unsigned int i;
>>>
>>> for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++,
>>> ratio++) { @@ -239,15 +239,15 @@
>>> tegra_actmon_account_cpu_freq(struct tegra_devfreq *tegra, struct
>>> tegra_devfreq_device *dev, unsigned long target_freq)
>>> {
>>> - unsigned long static_cpu_emc_freq;
>>> + unsigned long cpu_emc_freq = 0;
>>>
>>> - if (dev->config->avg_dependency_threshold &&
>>> - dev->config->avg_dependency_threshold < dev->avg_freq)
>>> {
>>> - static_cpu_emc_freq =
>>> actmon_cpu_to_emc_rate(tegra);
>>> - target_freq = max(target_freq,
>>> static_cpu_emc_freq);
>>> - }
>>> + if (!dev->config->avg_dependency_threshold)
>>> + return target_freq;
>>>
>>> - return target_freq;
>>> + if (dev->avg_freq > dev->config->avg_dependency_threshold)
>>> + cpu_emc_freq = actmon_cpu_to_emc_rate(tegra,
>>> cpufreq_get(0)); +
>>> + return max(target_freq, cpu_emc_freq);
>>> }
>>>
>>> static unsigned long tegra_actmon_lower_freq(struct tegra_devfreq
>>> *tegra, @@ -531,16 +531,71 @@ static void
>>> tegra_actmon_delayed_update(struct work_struct *work)
>>> mutex_unlock(&tegra->devfreq->lock); }
>>>
>>> +static unsigned long
>>> +tegra_actmon_cpufreq_contribution(struct tegra_devfreq *tegra,
>>> + unsigned int cpu_freq)
>>> +{
>>> + unsigned long freq, static_cpu_emc_freq;
>>> +
>>> + /* check whether CPU's freq is taken into account at all */
>>> + if (tegra->devices[MCCPU].avg_freq <=
>>> + tegra->devices[MCCPU].config->avg_dependency_threshold)
>>> + return 0;
>>> +
>>> + static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra,
>>> cpu_freq); +
>>> + /* compare static CPU-EMC freq with MCALL */
>>> + freq = tegra->devices[MCALL].avg_freq +
>>> + tegra->devices[MCALL].boost_freq;
>>> +
>>> + freq = tegra_actmon_upper_freq(tegra, freq);
>>> +
>>> + if (freq == tegra->max_freq || freq >= static_cpu_emc_freq)
>>> + return 0;
>>> +
>>> + /* compare static CPU-EMC freq with MCCPU */
>>> + freq = tegra->devices[MCCPU].avg_freq +
>>> + tegra->devices[MCCPU].boost_freq;
>>> +
>>> + freq = tegra_actmon_upper_freq(tegra, freq);
>>> +
>>> + if (freq == tegra->max_freq || freq >= static_cpu_emc_freq)
>>> + return 0;
>>> +
>>> + return static_cpu_emc_freq;
>>> +}
>>> +
>>> static int tegra_actmon_cpu_notify_cb(struct notifier_block *nb,
>>> unsigned long action, void
>>> *ptr) {
>>> + struct cpufreq_freqs *freqs = ptr;
>>> struct tegra_devfreq *tegra;
>>> + unsigned long old, new;
>>>
>>> if (action != CPUFREQ_POSTCHANGE)
>>> return NOTIFY_OK;
>>>
>>> tegra = container_of(nb, struct tegra_devfreq,
>>> cpu_rate_change_nb);
>>> + /*
>>> + * Quickly check whether CPU frequency should be taken
>>> into account
>>> + * at all, without blocking CPUFreq's core.
>>> + */
>>> + if (mutex_trylock(&tegra->devfreq->lock)) {
>>> + old = tegra_actmon_cpufreq_contribution(tegra,
>>> freqs->old);
>>> + new = tegra_actmon_cpufreq_contribution(tegra,
>>> freqs->new);
>>> + mutex_unlock(&tegra->devfreq->lock);
>>> +
>>> + /*
>>> + * If CPU's frequency shouldn't be taken into
>>> account at
>>> + * the moment, then there is no need to update the
>>> devfreq's
>>> + * state because ISR will re-check CPU's frequency
>>> on the
>>> + * next interrupt.
>>> + */
>>> + if (old == new)
>>> + return NOTIFY_OK;
>>> + }
>>> +
>>> /*
>>> * CPUFreq driver should support
>>> CPUFREQ_ASYNC_NOTIFICATION in order
>>> * to allow asynchronous notifications. This means we
>>> can't block
>>
>>
>
>
>

--
Best Regards,
Chanwoo Choi
Samsung Electronics