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[PATCH 07/15] cpufreq: ondemand: Simplify idle cputime granularity test

Frederic Weisbecker posted 15 patches 3 weeks, 1 day ago
There is a newer version of this series
[PATCH 07/15] cpufreq: ondemand: Simplify idle cputime granularity test
Posted by Frederic Weisbecker 3 weeks, 1 day ago 
cpufreq calls get_cpu_idle_time_us() just to know if idle cputime
accounting has a nanoseconds granularity.

Use the appropriate indicator instead to make that deduction.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 drivers/cpufreq/cpufreq_ondemand.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index a6ecc203f7b7..2d52ee035702 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -334,17 +334,12 @@ static void od_free(struct policy_dbs_info *policy_dbs)
 static int od_init(struct dbs_data *dbs_data)
 {
 	struct od_dbs_tuners *tuners;
-	u64 idle_time;
-	int cpu;
 
 	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
 	if (!tuners)
 		return -ENOMEM;
 
-	cpu = get_cpu();
-	idle_time = get_cpu_idle_time_us(cpu, NULL);
-	put_cpu();
-	if (idle_time != -1ULL) {
+	if (tick_nohz_enabled) {
 		/* Idle micro accounting is supported. Use finer thresholds */
 		dbs_data->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
 	} else {
-- 
2.51.1
Re: [PATCH 07/15] cpufreq: ondemand: Simplify idle cputime granularity test
Posted by Rafael J. Wysocki 2 weeks, 5 days ago 
On Fri, Jan 16, 2026 at 3:53 PM Frederic Weisbecker <frederic@kernel.org> wrote:
>
> cpufreq calls get_cpu_idle_time_us() just to know if idle cputime
> accounting has a nanoseconds granularity.
>
> Use the appropriate indicator instead to make that deduction.
>
> Signed-off-by: Frederic Weisbecker <frederic@kernel.org>

Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>

or please let me know if you want me to take this patch.

> ---
>  drivers/cpufreq/cpufreq_ondemand.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
> index a6ecc203f7b7..2d52ee035702 100644
> --- a/drivers/cpufreq/cpufreq_ondemand.c
> +++ b/drivers/cpufreq/cpufreq_ondemand.c
> @@ -334,17 +334,12 @@ static void od_free(struct policy_dbs_info *policy_dbs)
>  static int od_init(struct dbs_data *dbs_data)
>  {
>         struct od_dbs_tuners *tuners;
> -       u64 idle_time;
> -       int cpu;
>
>         tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
>         if (!tuners)
>                 return -ENOMEM;
>
> -       cpu = get_cpu();
> -       idle_time = get_cpu_idle_time_us(cpu, NULL);
> -       put_cpu();
> -       if (idle_time != -1ULL) {
> +       if (tick_nohz_enabled) {
>                 /* Idle micro accounting is supported. Use finer thresholds */
>                 dbs_data->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
>         } else {
> --
> 2.51.1
>
>
Re: [PATCH 07/15] cpufreq: ondemand: Simplify idle cputime granularity test
Posted by Frederic Weisbecker 2 weeks, 5 days ago 
Le Mon, Jan 19, 2026 at 01:30:07PM +0100, Rafael J. Wysocki a écrit :
> On Fri, Jan 16, 2026 at 3:53 PM Frederic Weisbecker <frederic@kernel.org> wrote:
> >
> > cpufreq calls get_cpu_idle_time_us() just to know if idle cputime
> > accounting has a nanoseconds granularity.
> >
> > Use the appropriate indicator instead to make that deduction.
> >
> > Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> 
> Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
> 
> or please let me know if you want me to take this patch.

The patch is standalone but the rest of the patchset depends on it.
Now I don't target this patchset for v6.20-rc1.

So if you manage to sneak this patch in for v6.20-rc1, it works because
I'll rebase on -rc1. Otherwise I'll need to keep it to avoid breaking
some code assumptions.

What do you think?

Thanks.

-- 
Frederic Weisbecker
SUSE Labs
Re: [PATCH 07/15] cpufreq: ondemand: Simplify idle cputime granularity test
Posted by Rafael J. Wysocki 2 weeks, 4 days ago 
On Mon, Jan 19, 2026 at 11:07 PM Frederic Weisbecker
<frederic@kernel.org> wrote:
>
> Le Mon, Jan 19, 2026 at 01:30:07PM +0100, Rafael J. Wysocki a écrit :
> > On Fri, Jan 16, 2026 at 3:53 PM Frederic Weisbecker <frederic@kernel.org> wrote:
> > >
> > > cpufreq calls get_cpu_idle_time_us() just to know if idle cputime
> > > accounting has a nanoseconds granularity.
> > >
> > > Use the appropriate indicator instead to make that deduction.
> > >
> > > Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> >
> > Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
> >
> > or please let me know if you want me to take this patch.
>
> The patch is standalone but the rest of the patchset depends on it.
> Now I don't target this patchset for v6.20-rc1.
>
> So if you manage to sneak this patch in for v6.20-rc1, it works because
> I'll rebase on -rc1. Otherwise I'll need to keep it to avoid breaking
> some code assumptions.
>
> What do you think?

It can go into -rc1.
Re: [PATCH 07/15] cpufreq: ondemand: Simplify idle cputime granularity test
Posted by Frederic Weisbecker 2 weeks, 4 days ago 
Le Tue, Jan 20, 2026 at 01:32:50PM +0100, Rafael J. Wysocki a écrit :
> On Mon, Jan 19, 2026 at 11:07 PM Frederic Weisbecker
> <frederic@kernel.org> wrote:
> >
> > Le Mon, Jan 19, 2026 at 01:30:07PM +0100, Rafael J. Wysocki a écrit :
> > > On Fri, Jan 16, 2026 at 3:53 PM Frederic Weisbecker <frederic@kernel.org> wrote:
> > > >
> > > > cpufreq calls get_cpu_idle_time_us() just to know if idle cputime
> > > > accounting has a nanoseconds granularity.
> > > >
> > > > Use the appropriate indicator instead to make that deduction.
> > > >
> > > > Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> > >
> > > Acked-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
> > >
> > > or please let me know if you want me to take this patch.
> >
> > The patch is standalone but the rest of the patchset depends on it.
> > Now I don't target this patchset for v6.20-rc1.
> >
> > So if you manage to sneak this patch in for v6.20-rc1, it works because
> > I'll rebase on -rc1. Otherwise I'll need to keep it to avoid breaking
> > some code assumptions.
> >
> > What do you think?
> 
> It can go into -rc1.

Very nice, thanks for taking it!


-- 
Frederic Weisbecker
SUSE Labs
Re: [PATCH 07/15] cpufreq: ondemand: Simplify idle cputime granularity test
Posted by Viresh Kumar 2 weeks, 5 days ago 
On 16-01-26, 15:52, Frederic Weisbecker wrote:
> cpufreq calls get_cpu_idle_time_us() just to know if idle cputime
> accounting has a nanoseconds granularity.
> 
> Use the appropriate indicator instead to make that deduction.
> 
> Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
> ---
>  drivers/cpufreq/cpufreq_ondemand.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
> index a6ecc203f7b7..2d52ee035702 100644
> --- a/drivers/cpufreq/cpufreq_ondemand.c
> +++ b/drivers/cpufreq/cpufreq_ondemand.c
> @@ -334,17 +334,12 @@ static void od_free(struct policy_dbs_info *policy_dbs)
>  static int od_init(struct dbs_data *dbs_data)
>  {
>  	struct od_dbs_tuners *tuners;
> -	u64 idle_time;
> -	int cpu;
>  
>  	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
>  	if (!tuners)
>  		return -ENOMEM;
>  
> -	cpu = get_cpu();
> -	idle_time = get_cpu_idle_time_us(cpu, NULL);
> -	put_cpu();
> -	if (idle_time != -1ULL) {
> +	if (tick_nohz_enabled) {
>  		/* Idle micro accounting is supported. Use finer thresholds */
>  		dbs_data->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
>  	} else {

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh

Patchew 2.1-devel-b67e4c2

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