From: Chanwoo Choi <cw00.choi@samsung.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Tomeu Vizoso <tomeu.vizoso@collabora.com>,
linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 20/24] PM / devfreq: tegra30: Optimize upper average watermark selection
Date: Wed, 24 Jul 2019 20:17:45 +0900 [thread overview]
Message-ID: <6fa38946-7441-4c19-83fd-4da422be5732@samsung.com> (raw)
In-Reply-To: <01b442e4-437d-799d-ed0d-4628bd0d683b@gmail.com>
On 19. 7. 20. 오전 2:52, Dmitry Osipenko wrote:
> 19.07.2019 9:11, Chanwoo Choi пишет:
>> On 19. 7. 19. 오후 3:09, Chanwoo Choi wrote:
>>> On 19. 7. 19. 오전 11:21, Dmitry Osipenko wrote:
>>>> В Fri, 19 Jul 2019 11:06:05 +0900
>>>> Chanwoo Choi <cw00.choi@samsung.com> пишет:
>>>>
>>>>> On 19. 7. 19. 오전 10:59, Dmitry Osipenko wrote:
>>>>>> В Fri, 19 Jul 2019 10:36:30 +0900
>>>>>> Chanwoo Choi <cw00.choi@samsung.com> пишет:
>>>>>>
>>>>>>> On 19. 7. 8. 오전 7:32, Dmitry Osipenko wrote:
>>>>>>>> I noticed that CPU may be crossing the dependency threshold very
>>>>>>>> frequently for some workloads and this results in a lot of
>>>>>>>> interrupts which could be avoided if MCALL client is keeping
>>>>>>>> actual EMC frequency at a higher rate.
>>>>>>>>
>>>>>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>>>>>>>> ---
>>>>>>>> drivers/devfreq/tegra30-devfreq.c | 23 ++++++++++++++++++-----
>>>>>>>> 1 file changed, 18 insertions(+), 5 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/drivers/devfreq/tegra30-devfreq.c
>>>>>>>> b/drivers/devfreq/tegra30-devfreq.c index
>>>>>>>> c3cf87231d25..4d582809acb6 100644 ---
>>>>>>>> a/drivers/devfreq/tegra30-devfreq.c +++
>>>>>>>> b/drivers/devfreq/tegra30-devfreq.c @@ -314,7 +314,8 @@ static
>>>>>>>> void tegra_actmon_get_lower_upper(struct tegra_devfreq *tegra, }
>>>>>>>>
>>>>>>>> static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq
>>>>>>>> *tegra,
>>>>>>>> - struct
>>>>>>>> tegra_devfreq_device *dev)
>>>>>>>> + struct
>>>>>>>> tegra_devfreq_device *dev,
>>>>>>>> + unsigned long freq)
>>>>>>>> {
>>>>>>>> unsigned long avg_threshold, lower, upper;
>>>>>>>>
>>>>>>>> @@ -323,6 +324,15 @@ static void
>>>>>>>> tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
>>>>>>>> avg_threshold = dev->config->avg_dependency_threshold;
>>>>>>>> avg_threshold = avg_threshold * ACTMON_SAMPLING_PERIOD;
>>>>>>>> + /*
>>>>>>>> + * If cumulative EMC frequency selection is higher than
>>>>>>>> the
>>>>>>>> + * device's, then there is no need to set upper watermark
>>>>>>>> to
>>>>>>>> + * a lower value because it will result in unnecessary
>>>>>>>> upper
>>>>>>>> + * interrupts.
>>>>>>>> + */
>>>>>>>> + if (freq * ACTMON_SAMPLING_PERIOD > upper)
>>>>>>>> + upper = freq * ACTMON_SAMPLING_PERIOD;
>>>>>>>
>>>>>>> Also, 'upper value is used on the patch5. You can combine this code
>>>>>>> to patch5 or if this patch depends on the cpu notifier, you can
>>>>>>> combine it to the patch of adding cpu notifier without separate
>>>>>>> patch.
>>>>>>
>>>>>> Well okay, I'll try to squash some of the patches in the next
>>>>>> revision. Usually I'm receiving comments in the other direction,
>>>>>> asking to separate patches into smaller changes ;) So that's more a
>>>>>> personal preference of each maintainer, I'd say.
>>>>>>
>>>>>
>>>>> Right. We have to make the patch with atomic attribute.
>>>>> But, if there are patches which touch the same code
>>>>> in the same patchset. We can squash or do refactorig
>>>>> of this code.
>>>>
>>>> The main benefit of having smaller logical changes is that when there is
>>>> a bug, it's easier to narrow down the offending change using bisection.
>>>> And it's just easier to review smaller patches, of course.
>>>
>>> I agree that the patch should contain the atomic feature.
>>> To remove the some communication confusion between us,
>>> I don't mean that you have to merge patches to only one patch.
>>
>> If each patch has the atomic attribute, it have to be made as the separate patch.
>> But, if some patches are included in the the following two case,
>> can combine patches to one patch.
>>
>>>
>>> It is important to remove the following two cases on the same patchset.
>>>
>>> 1. the front patch adds the code and then later patch remove the added code.
>
> Okay, I agree that this is applicable to patch #11.
>
>>> 2. the front patch changes the code and the later patch again modified
>>> the changed code of the front patch
>
> If patch A adds a new feature and then patch B adds another new feature
> on top of A, do you consider each of these patches as atomic?
Yes, if patch A and patch A have the different role
for the same device driver, it is possible to make them
as the separate patches.
>
> [snip]
>
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
next prev parent reply other threads:[~2019-07-24 11:14 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-07 22:32 [PATCH v4 00/24] More improvements for Tegra30 devfreq driver Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 01/24] PM / devfreq: tegra30: Change irq type to unsigned int Dmitry Osipenko
2019-07-16 11:35 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 02/24] PM / devfreq: tegra30: Keep interrupt disabled while governor is stopped Dmitry Osipenko
2019-07-16 11:47 ` Chanwoo Choi
2019-07-16 13:03 ` Dmitry Osipenko
2019-07-17 6:37 ` Chanwoo Choi
2019-07-17 16:44 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 03/24] PM / devfreq: tegra30: Handle possible round-rate error Dmitry Osipenko
2019-07-16 11:50 ` Chanwoo Choi
2019-07-16 13:09 ` Dmitry Osipenko
2019-07-17 6:38 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 04/24] PM / devfreq: tegra30: Drop write-barrier Dmitry Osipenko
2019-07-16 11:51 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 05/24] PM / devfreq: tegra30: Set up watermarks properly Dmitry Osipenko
2019-07-18 10:17 ` Chanwoo Choi
2019-07-19 0:00 ` Dmitry Osipenko
2019-07-19 1:31 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 06/24] PM / devfreq: tegra30: Tune up boosting thresholds Dmitry Osipenko
2019-07-16 11:55 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 07/24] PM / devfreq: tegra30: Use CPUFreq notifier Dmitry Osipenko
2019-07-16 12:08 ` Chanwoo Choi
2019-07-16 13:18 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 08/24] PM / devfreq: tegra30: Move clk-notifier's registration to governor's start Dmitry Osipenko
2019-07-16 12:11 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 09/24] PM / devfreq: tegra30: Reset boosting on startup Dmitry Osipenko
2019-07-16 12:13 ` Chanwoo Choi
2019-07-16 13:19 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 10/24] PM / devfreq: tegra30: Don't enable consecutive-down interrupt " Dmitry Osipenko
2019-07-16 12:17 ` Chanwoo Choi
2019-07-16 15:17 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 11/24] PM / devfreq: tegra30: Add debug messages Dmitry Osipenko
2019-07-16 12:23 ` Chanwoo Choi
2019-07-16 13:26 ` Dmitry Osipenko
2019-07-17 6:45 ` Chanwoo Choi
2019-07-17 15:46 ` Dmitry Osipenko
2019-07-18 9:07 ` Chanwoo Choi
2019-07-19 1:13 ` Dmitry Osipenko
2019-07-19 1:22 ` Chanwoo Choi
2019-07-19 17:10 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 12/24] PM / devfreq: tegra30: Inline all one-line functions Dmitry Osipenko
2019-07-16 12:26 ` Chanwoo Choi
2019-07-16 13:35 ` Dmitry Osipenko
2019-07-18 9:09 ` Chanwoo Choi
2019-07-19 1:22 ` Dmitry Osipenko
2019-07-19 1:24 ` Chanwoo Choi
2019-07-19 1:27 ` Chanwoo Choi
2019-07-19 2:14 ` Dmitry Osipenko
2019-07-19 6:01 ` Chanwoo Choi
2019-07-19 16:52 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 13/24] PM / devfreq: tegra30: Constify structs Dmitry Osipenko
2019-07-16 12:26 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 14/24] PM / devfreq: tegra30: Ensure that target freq won't overflow Dmitry Osipenko
2019-07-16 12:30 ` Chanwoo Choi
2019-07-16 13:59 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 15/24] PM / devfreq: tegra30: Fix integer overflow on CPU's freq max out Dmitry Osipenko
2019-07-16 12:32 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 16/24] PM / devfreq: tegra30: Use kHz units uniformly in the code Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 17/24] PM / devfreq: tegra30: Use tracepoints for debugging Dmitry Osipenko
2019-07-18 9:47 ` Chanwoo Choi
2019-07-19 0:49 ` Dmitry Osipenko
2019-07-19 1:01 ` Chanwoo Choi
2019-07-19 1:50 ` Dmitry Osipenko
2019-07-07 22:32 ` [PATCH v4 18/24] PM / devfreq: tegra30: Optimize CPUFreq notifier Dmitry Osipenko
2019-07-18 9:48 ` Chanwoo Choi
2019-07-19 0:42 ` Dmitry Osipenko
2019-07-19 1:09 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 19/24] PM / devfreq: tegra30: Optimize upper consecutive watermark selection Dmitry Osipenko
2019-07-18 9:51 ` Chanwoo Choi
2019-07-19 0:40 ` Dmitry Osipenko
2019-07-19 1:15 ` Chanwoo Choi
2019-07-19 1:17 ` Chanwoo Choi
2019-07-07 22:32 ` [PATCH v4 20/24] PM / devfreq: tegra30: Optimize upper average " Dmitry Osipenko
2019-07-19 1:36 ` Chanwoo Choi
2019-07-19 1:59 ` Dmitry Osipenko
2019-07-19 2:06 ` Chanwoo Choi
2019-07-19 2:21 ` Dmitry Osipenko
2019-07-19 6:09 ` Chanwoo Choi
2019-07-19 6:11 ` Chanwoo Choi
2019-07-19 17:52 ` Dmitry Osipenko
2019-07-24 11:17 ` Chanwoo Choi [this message]
2019-07-24 11:19 ` Chanwoo Choi
2019-07-07 22:33 ` [PATCH v4 21/24] PM / devfreq: tegra30: Synchronize average count on target's update Dmitry Osipenko
2019-07-18 10:15 ` Chanwoo Choi
2019-07-19 0:31 ` Dmitry Osipenko
2019-07-19 1:40 ` Chanwoo Choi
2019-07-19 16:46 ` Dmitry Osipenko
2019-07-07 22:33 ` [PATCH v4 22/24] PM / devfreq: tegra30: Include appropriate header Dmitry Osipenko
2019-07-18 9:58 ` Chanwoo Choi
2019-07-19 0:34 ` Dmitry Osipenko
2019-07-07 22:33 ` [PATCH v4 23/24] PM / devfreq: tegra30: Increase sampling period to 16ms Dmitry Osipenko
2019-07-18 10:00 ` Chanwoo Choi
2019-07-07 22:33 ` [PATCH v4 24/24] PM / devfreq: tegra20/30: Add Dmitry as a maintainer Dmitry Osipenko
2019-07-18 9:56 ` Chanwoo Choi
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