[v4,19/24] PM / devfreq: tegra30: Optimize upper consecutive watermark selection
diff mbox series

Message ID 20190707223303.6755-20-digetx@gmail.com
State New
Headers show
Series
  • More improvements for Tegra30 devfreq driver
Related show

Commit Message

Dmitry Osipenko July 7, 2019, 10:32 p.m. UTC
The memory activity counter may get a bit higher than a watermark which
is selected based on OPP that corresponds to a highest EMC rate, in this
case watermark is lower than the actual memory activity is and thus
results in unwanted "upper" interrupts.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/devfreq/tegra30-devfreq.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

Comments

Chanwoo Choi July 18, 2019, 9:51 a.m. UTC | #1
On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
> The memory activity counter may get a bit higher than a watermark which
> is selected based on OPP that corresponds to a highest EMC rate, in this
> case watermark is lower than the actual memory activity is and thus
> results in unwanted "upper" interrupts.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/devfreq/tegra30-devfreq.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)

It seems that you can combine patch19 with patch20.

> 
> diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
> index 8d6bf6e9f1ae..c3cf87231d25 100644
> --- a/drivers/devfreq/tegra30-devfreq.c
> +++ b/drivers/devfreq/tegra30-devfreq.c
> @@ -363,7 +363,18 @@ static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
>  	tegra_actmon_get_lower_upper(tegra, dev, freq - 1, &lower, &upper);
>  
>  	delta = do_percent(upper - lower, dev->config->boost_up_threshold);
> -	device_writel(dev, lower + delta, ACTMON_DEV_UPPER_WMARK);
> +
> +	/*
> +	 * The memory events count could go a bit higher than the maximum
> +	 * defined by the OPPs, hence make the upper watermark infinitely
> +	 * high to avoid unnecessary upper interrupts in that case.
> +	 */
> +	if (freq == tegra->max_freq)
> +		upper = ULONG_MAX;
> +	else
> +		upper = lower + delta;
> +
> +	device_writel(dev, upper, ACTMON_DEV_UPPER_WMARK);
>  
>  	/*
>  	 * Meanwhile the lower mark is based on the average value
>
Dmitry Osipenko July 19, 2019, 12:40 a.m. UTC | #2
В Thu, 18 Jul 2019 18:51:02 +0900
Chanwoo Choi <cw00.choi@samsung.com> пишет:

> On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
> > The memory activity counter may get a bit higher than a watermark
> > which is selected based on OPP that corresponds to a highest EMC
> > rate, in this case watermark is lower than the actual memory
> > activity is and thus results in unwanted "upper" interrupts.
> > 
> > Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> > ---
> >  drivers/devfreq/tegra30-devfreq.c | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)  
> 
> It seems that you can combine patch19 with patch20.

No, consecutive and average watermarks are different things that have
different purposes. Consecutive are used for boosting, while average
are for significant memory bandwidth changes.

> > 
> > diff --git a/drivers/devfreq/tegra30-devfreq.c
> > b/drivers/devfreq/tegra30-devfreq.c index
> > 8d6bf6e9f1ae..c3cf87231d25 100644 ---
> > a/drivers/devfreq/tegra30-devfreq.c +++
> > b/drivers/devfreq/tegra30-devfreq.c @@ -363,7 +363,18 @@ static
> > void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
> > tegra_actmon_get_lower_upper(tegra, dev, freq - 1, &lower, &upper); 
> >  	delta = do_percent(upper - lower,
> > dev->config->boost_up_threshold);
> > -	device_writel(dev, lower + delta, ACTMON_DEV_UPPER_WMARK);
> > +
> > +	/*
> > +	 * The memory events count could go a bit higher than the
> > maximum
> > +	 * defined by the OPPs, hence make the upper watermark
> > infinitely
> > +	 * high to avoid unnecessary upper interrupts in that case.
> > +	 */
> > +	if (freq == tegra->max_freq)
> > +		upper = ULONG_MAX;
> > +	else
> > +		upper = lower + delta;
> > +
> > +	device_writel(dev, upper, ACTMON_DEV_UPPER_WMARK);
> >  
> >  	/*
> >  	 * Meanwhile the lower mark is based on the average value
> >   
> 
>
Chanwoo Choi July 19, 2019, 1:15 a.m. UTC | #3
On 19. 7. 19. 오전 9:40, Dmitry Osipenko wrote:
> В Thu, 18 Jul 2019 18:51:02 +0900
> Chanwoo Choi <cw00.choi@samsung.com> пишет:
> 
>> On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
>>> The memory activity counter may get a bit higher than a watermark
>>> which is selected based on OPP that corresponds to a highest EMC
>>> rate, in this case watermark is lower than the actual memory
>>> activity is and thus results in unwanted "upper" interrupts.
>>>
>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>>> ---
>>>  drivers/devfreq/tegra30-devfreq.c | 13 ++++++++++++-
>>>  1 file changed, 12 insertions(+), 1 deletion(-)  
>>
>> It seems that you can combine patch19 with patch20.
> 
> No, consecutive and average watermarks are different things that have
> different purposes. Consecutive are used for boosting, while average
> are for significant memory bandwidth changes.
> 
>>>
>>> diff --git a/drivers/devfreq/tegra30-devfreq.c
>>> b/drivers/devfreq/tegra30-devfreq.c index
>>> 8d6bf6e9f1ae..c3cf87231d25 100644 ---
>>> a/drivers/devfreq/tegra30-devfreq.c +++
>>> b/drivers/devfreq/tegra30-devfreq.c @@ -363,7 +363,18 @@ static
>>> void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
>>> tegra_actmon_get_lower_upper(tegra, dev, freq - 1, &lower, &upper); 
>>>  	delta = do_percent(upper - lower,
>>> dev->config->boost_up_threshold);
>>> -	device_writel(dev, lower + delta, ACTMON_DEV_UPPER_WMARK);

This line was added on patch5 and then this line is removed on this patch.
It is wrong method to make the patch in the same patchset.

It is enough to reduce the inefficient add/remove code in the same patchset.

Have to merge this patch to patch5.

>>> +
>>> +	/*
>>> +	 * The memory events count could go a bit higher than the
>>> maximum
>>> +	 * defined by the OPPs, hence make the upper watermark
>>> infinitely
>>> +	 * high to avoid unnecessary upper interrupts in that case.
>>> +	 */
>>> +	if (freq == tegra->max_freq)
>>> +		upper = ULONG_MAX;
>>> +	else
>>> +		upper = lower + delta;
>>> +
>>> +	device_writel(dev, upper, ACTMON_DEV_UPPER_WMARK);
>>>  
>>>  	/*
>>>  	 * Meanwhile the lower mark is based on the average value
>>>   
>>
>>
> 
> 
>
Chanwoo Choi July 19, 2019, 1:17 a.m. UTC | #4
On 19. 7. 19. 오전 10:15, Chanwoo Choi wrote:
> On 19. 7. 19. 오전 9:40, Dmitry Osipenko wrote:
>> В Thu, 18 Jul 2019 18:51:02 +0900
>> Chanwoo Choi <cw00.choi@samsung.com> пишет:
>>
>>> On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
>>>> The memory activity counter may get a bit higher than a watermark
>>>> which is selected based on OPP that corresponds to a highest EMC
>>>> rate, in this case watermark is lower than the actual memory
>>>> activity is and thus results in unwanted "upper" interrupts.
>>>>
>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>>>> ---
>>>>  drivers/devfreq/tegra30-devfreq.c | 13 ++++++++++++-
>>>>  1 file changed, 12 insertions(+), 1 deletion(-)  
>>>
>>> It seems that you can combine patch19 with patch20.
>>
>> No, consecutive and average watermarks are different things that have
>> different purposes. Consecutive are used for boosting, while average
>> are for significant memory bandwidth changes.
>>
>>>>
>>>> diff --git a/drivers/devfreq/tegra30-devfreq.c
>>>> b/drivers/devfreq/tegra30-devfreq.c index
>>>> 8d6bf6e9f1ae..c3cf87231d25 100644 ---
>>>> a/drivers/devfreq/tegra30-devfreq.c +++
>>>> b/drivers/devfreq/tegra30-devfreq.c @@ -363,7 +363,18 @@ static
>>>> void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
>>>> tegra_actmon_get_lower_upper(tegra, dev, freq - 1, &lower, &upper); 
>>>>  	delta = do_percent(upper - lower,
>>>> dev->config->boost_up_threshold);
>>>> -	device_writel(dev, lower + delta, ACTMON_DEV_UPPER_WMARK);
> 
> This line was added on patch5 and then this line is removed on this patch.
> It is wrong method to make the patch in the same patchset.
> 
> It is enough to reduce the inefficient add/remove code in the same patchset.

I'm missing some expression. So, I update my comment as following:
It is possible to reduce the inefficient add/remove code in the same patchset
if you combine the patches.

> 
> Have to merge this patch to patch5.
> 
>>>> +
>>>> +	/*
>>>> +	 * The memory events count could go a bit higher than the
>>>> maximum
>>>> +	 * defined by the OPPs, hence make the upper watermark
>>>> infinitely
>>>> +	 * high to avoid unnecessary upper interrupts in that case.
>>>> +	 */
>>>> +	if (freq == tegra->max_freq)
>>>> +		upper = ULONG_MAX;
>>>> +	else
>>>> +		upper = lower + delta;
>>>> +
>>>> +	device_writel(dev, upper, ACTMON_DEV_UPPER_WMARK);
>>>>  
>>>>  	/*
>>>>  	 * Meanwhile the lower mark is based on the average value
>>>>   
>>>
>>>
>>
>>
>>
> 
>

Patch
diff mbox series

diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index 8d6bf6e9f1ae..c3cf87231d25 100644
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -363,7 +363,18 @@  static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
 	tegra_actmon_get_lower_upper(tegra, dev, freq - 1, &lower, &upper);
 
 	delta = do_percent(upper - lower, dev->config->boost_up_threshold);
-	device_writel(dev, lower + delta, ACTMON_DEV_UPPER_WMARK);
+
+	/*
+	 * The memory events count could go a bit higher than the maximum
+	 * defined by the OPPs, hence make the upper watermark infinitely
+	 * high to avoid unnecessary upper interrupts in that case.
+	 */
+	if (freq == tegra->max_freq)
+		upper = ULONG_MAX;
+	else
+		upper = lower + delta;
+
+	device_writel(dev, upper, ACTMON_DEV_UPPER_WMARK);
 
 	/*
 	 * Meanwhile the lower mark is based on the average value