[PATCH] cpufreq: schedutil: Update last_update from sugov_set_iowait_boost()

[PATCH] cpufreq: schedutil: Update last_update from sugov_set_iowait_boost()

[Viresh Kumar]

sg_cpu->last_update is always updated right after we call
sugov_set_iowait_boost() and its better to update it from that routine
itself. This makes it more readable.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 kernel/sched/cpufreq_schedutil.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 29a397067ffa..63557b9f36b6 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -177,6 +177,8 @@ static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
 		if (delta_ns > TICK_NSEC)
 			sg_cpu->iowait_boost = 0;
 	}
+
+	sg_cpu->last_update = time;
 }
 
 static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util,
@@ -219,7 +221,6 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
 	bool busy;
 
 	sugov_set_iowait_boost(sg_cpu, time, flags);
-	sg_cpu->last_update = time;
 
 	if (!sugov_should_update_freq(sg_policy, time))
 		return;
@@ -299,7 +300,6 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
 	sg_cpu->flags = flags;
 
 	sugov_set_iowait_boost(sg_cpu, time, flags);
-	sg_cpu->last_update = time;
 
 	if (sugov_should_update_freq(sg_policy, time)) {
 		if (flags & SCHED_CPUFREQ_RT_DL)
-- 
2.13.0.71.gd7076ec9c9cb

Re: [PATCH] cpufreq: schedutil: Update last_update from sugov_set_iowait_boost()

[Juri Lelli]

Hi Viresh,

On 18/07/17 10:24, Viresh Kumar wrote:
> sg_cpu->last_update is always updated right after we call
> sugov_set_iowait_boost() and its better to update it from that routine
> itself. This makes it more readable.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  kernel/sched/cpufreq_schedutil.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> index 29a397067ffa..63557b9f36b6 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -177,6 +177,8 @@ static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
>  		if (delta_ns > TICK_NSEC)
>  			sg_cpu->iowait_boost = 0;
>  	}
> +
> +	sg_cpu->last_update = time;
>  }
>  
>  static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util,
> @@ -219,7 +221,6 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
>  	bool busy;
>  
>  	sugov_set_iowait_boost(sg_cpu, time, flags);
> -	sg_cpu->last_update = time;
>  
>  	if (!sugov_should_update_freq(sg_policy, time))
>  		return;
> @@ -299,7 +300,6 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
>  	sg_cpu->flags = flags;
>  
>  	sugov_set_iowait_boost(sg_cpu, time, flags);
> -	sg_cpu->last_update = time;

It actually belongs here, IMHO. We update other fields (util, max,
flags) before looking at iowait. Why hiding the time update into a
function dealing with only one of such fields?

Best,

- Juri

Re: [PATCH] cpufreq: schedutil: Update last_update from sugov_set_iowait_boost()

[Viresh Kumar]

On 18-07-17, 12:20, Juri Lelli wrote:
> Hi Viresh,
> 
> On 18/07/17 10:24, Viresh Kumar wrote:
> > sg_cpu->last_update is always updated right after we call
> > sugov_set_iowait_boost() and its better to update it from that routine
> > itself. This makes it more readable.
> > 
> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> > ---
> >  kernel/sched/cpufreq_schedutil.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
> > index 29a397067ffa..63557b9f36b6 100644
> > --- a/kernel/sched/cpufreq_schedutil.c
> > +++ b/kernel/sched/cpufreq_schedutil.c
> > @@ -177,6 +177,8 @@ static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
> >  		if (delta_ns > TICK_NSEC)
> >  			sg_cpu->iowait_boost = 0;
> >  	}
> > +
> > +	sg_cpu->last_update = time;
> >  }
> >  
> >  static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util,
> > @@ -219,7 +221,6 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
> >  	bool busy;
> >  
> >  	sugov_set_iowait_boost(sg_cpu, time, flags);
> > -	sg_cpu->last_update = time;
> >  
> >  	if (!sugov_should_update_freq(sg_policy, time))
> >  		return;
> > @@ -299,7 +300,6 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
> >  	sg_cpu->flags = flags;
> >  
> >  	sugov_set_iowait_boost(sg_cpu, time, flags);
> > -	sg_cpu->last_update = time;
> 
> It actually belongs here, IMHO. We update other fields (util, max,
> flags)

Yeah, because they have bigger roles and aren't specific to iowait
boost.

> before looking at iowait. Why hiding the time update into a
> function dealing with only one of such fields?

But last_update is very much specific to iowait_boost only and so it
should be updated from sugov_set_iowait_boost() IMHO.

-- 
viresh

Re: [PATCH] cpufreq: schedutil: Update last_update from sugov_set_iowait_boost()

[Juri Lelli]

On 18/07/17 16:55, Viresh Kumar wrote:
> On 18-07-17, 12:20, Juri Lelli wrote:
> > Hi Viresh,
> > 
> > On 18/07/17 10:24, Viresh Kumar wrote:

[...]

> > 
> > It actually belongs here, IMHO. We update other fields (util, max,
> > flags)
> 
> Yeah, because they have bigger roles and aren't specific to iowait
> boost.
> 
> > before looking at iowait. Why hiding the time update into a
> > function dealing with only one of such fields?
> 
> But last_update is very much specific to iowait_boost only and so it
> should be updated from sugov_set_iowait_boost() IMHO.
> 

Huh, I see you point. However, I'm using it also to deal with stale CFS
util values in my patches [1]. Sure, not mainline yet, but I guess I'll
have to sort of revert your proposed change for my next version. Or
think of a better idea. :)

Thanks,

- Juri

[1] http://marc.info/?l=linux-kernel&m=149924526528298&w=2

Re: [PATCH] cpufreq: schedutil: Update last_update from sugov_set_iowait_boost()

[Rafael J. Wysocki]

On Tuesday, July 18, 2017 12:35:52 PM Juri Lelli wrote:
> On 18/07/17 16:55, Viresh Kumar wrote:
> > On 18-07-17, 12:20, Juri Lelli wrote:
> > > Hi Viresh,
> > > 
> > > On 18/07/17 10:24, Viresh Kumar wrote:
> 
> [...]
> 
> > > 
> > > It actually belongs here, IMHO. We update other fields (util, max,
> > > flags)
> > 
> > Yeah, because they have bigger roles and aren't specific to iowait
> > boost.
> > 
> > > before looking at iowait. Why hiding the time update into a
> > > function dealing with only one of such fields?
> > 
> > But last_update is very much specific to iowait_boost only and so it
> > should be updated from sugov_set_iowait_boost() IMHO.
> > 
> 
> Huh, I see you point. However, I'm using it also to deal with stale CFS
> util values in my patches [1]. Sure, not mainline yet, but I guess I'll
> have to sort of revert your proposed change for my next version. Or
> think of a better idea. :)

Yes, so I'd prefer to prioritize your patches.

The patch from Viresh is purely cosmetic AFAICS and it really can wait.

Thanks,
Rafael