Re: [PATCH v3] cpufreq: trace frequency limits change

From: Steven Rostedt
Date: Wed Jul 25 2018 - 09:18:08 EST


On Tue, 24 Jul 2018 10:35:44 -0700
Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> wrote:

> From: Ruchi Kandoi <kandoiruchi@xxxxxxxxxx>
>
> systrace used for tracing for Android systems has carried a patch for
> many years in the Android tree that traces when the cpufreq limits
> change. With the help of this information, systrace can know when the
> policy limits change and can visually display the data. Lets add
> upstream support for the same.
>
> Signed-off-by: Ruchi Kandoi <kandoiruchi@xxxxxxxxxx>
> Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>

Better ;-)

Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>

-- Steve

> ---
> Viresh since I changed the patch, could you Ack it again?
>
> v2->v3: reduce parameters to tracepoint call (Steve)
> v1->v2: correct ordering of min/max (Viresh)
>
> Documentation/trace/events-power.rst | 1 +
> drivers/cpufreq/cpufreq.c | 1 +
> include/trace/events/power.h | 25 +++++++++++++++++++++++++
> 3 files changed, 27 insertions(+)
>
> diff --git a/Documentation/trace/events-power.rst b/Documentation/trace/events-power.rst
> index a77daca75e30..2ef318962e29 100644
> --- a/Documentation/trace/events-power.rst
> +++ b/Documentation/trace/events-power.rst
> @@ -27,6 +27,7 @@ cpufreq.
>
> cpu_idle "state=%lu cpu_id=%lu"
> cpu_frequency "state=%lu cpu_id=%lu"
> + cpu_frequency_limits "min=%lu max=%lu cpu_id=%lu"
>
> A suspend event is used to indicate the system going in and out of the
> suspend mode:
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index b0dfd3222013..52566f1f1050 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -2236,6 +2236,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
>
> policy->min = new_policy->min;
> policy->max = new_policy->max;
> + trace_cpu_frequency_limits(policy);
>
> policy->cached_target_freq = UINT_MAX;
>
> diff --git a/include/trace/events/power.h b/include/trace/events/power.h
> index 908977d69783..f7aece721aed 100644
> --- a/include/trace/events/power.h
> +++ b/include/trace/events/power.h
> @@ -5,6 +5,7 @@
> #if !defined(_TRACE_POWER_H) || defined(TRACE_HEADER_MULTI_READ)
> #define _TRACE_POWER_H
>
> +#include <linux/cpufreq.h>
> #include <linux/ktime.h>
> #include <linux/pm_qos.h>
> #include <linux/tracepoint.h>
> @@ -148,6 +149,30 @@ DEFINE_EVENT(cpu, cpu_frequency,
> TP_ARGS(frequency, cpu_id)
> );
>
> +TRACE_EVENT(cpu_frequency_limits,
> +
> + TP_PROTO(struct cpufreq_policy *policy),
> +
> + TP_ARGS(policy),
> +
> + TP_STRUCT__entry(
> + __field(u32, min_freq)
> + __field(u32, max_freq)
> + __field(u32, cpu_id)
> + ),
> +
> + TP_fast_assign(
> + __entry->min_freq = policy->min;
> + __entry->max_freq = policy->max;
> + __entry->cpu_id = policy->cpu;
> + ),
> +
> + TP_printk("min=%lu max=%lu cpu_id=%lu",
> + (unsigned long)__entry->min_freq,
> + (unsigned long)__entry->max_freq,
> + (unsigned long)__entry->cpu_id)
> +);
> +
> TRACE_EVENT(device_pm_callback_start,
>
> TP_PROTO(struct device *dev, const char *pm_ops, int event),