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From: Chanwoo Choi <cw00.choi@samsung.com>
To: Lukasz Luba <l.luba@partner.samsung.com>,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org
Cc: b.zolnierkie@samsung.com, myungjoo.ham@samsung.com,
	kyungmin.park@samsung.com, m.szyprowski@samsung.com,
	s.nawrocki@samsung.com, joel@joelfernandes.org,
	chris.diamand@arm.com, mka@chromium.org, rostedt@goodmis.org,
	mingo@redhat.com
Subject: Re: [PATCH v3 1/7] drivers: devfreq: change deferred work into delayed
Date: Thu, 14 Feb 2019 13:10:26 +0900	[thread overview]
Message-ID: <85f58e8e-53f7-c622-59f7-82f7e04ab6ac@samsung.com> (raw)
In-Reply-To: <1550010238-24002-2-git-send-email-l.luba@partner.samsung.com>

Hi Lukasz,

On 19. 2. 13. 오전 7:23, Lukasz Luba wrote:
> This patch changes deferred work to delayed work, which is now not missed
> when timer is put on CPU that entered idle state.
> The devfreq framework governor was not called, thus changing the device's
> frequency did not happen.
> Benchmarks for stressing Dynamic Memory Controller show x2 (in edge cases
> even x5) performance boost with this patch when 'simpleondemand_governor'
> is responsible for monitoring the device load and frequency changes.
> 
> With this patch, the delayed work is done no mater CPUs' idle.
> All of the drivers in devfreq which rely on periodic, guaranteed wakeup
> intervals should benefit from it.
> 
> Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
> ---
>  drivers/devfreq/devfreq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 0ae3de7..0c9bff8 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -407,7 +407,7 @@ static void devfreq_monitor(struct work_struct *work)
>   */
>  void devfreq_monitor_start(struct devfreq *devfreq)
>  {
> -	INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
> +	INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);

As I commented, I can't agree that just changing the type of work
from deferrable to delayed for the always periodic timer.

Instead, if devfreq framework supports both deferrable
and delayed work according to selecting the kind of work
by user, I agree.

>  	if (devfreq->profile->polling_ms)
>  		queue_delayed_work(devfreq_wq, &devfreq->work,
>  			msecs_to_jiffies(devfreq->profile->polling_ms));
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

  reply	other threads:[~2019-02-14  4:10 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20190212222422eucas1p1624203db4db3e495035820dea542e23a@eucas1p1.samsung.com>
2019-02-12 22:23 ` [PATCH v3 0/7] drivers: devfreq: fix and optimize workqueue mechanism Lukasz Luba
     [not found]   ` <CGME20190212222430eucas1p1ad7992e29d224790c1e20ef7442e62fe@eucas1p1.samsung.com>
2019-02-12 22:23     ` [PATCH v3 1/7] drivers: devfreq: change deferred work into delayed Lukasz Luba
2019-02-14  4:10       ` Chanwoo Choi [this message]
     [not found]   ` <CGME20190212222431eucas1p1697607e6536a90283cf7dad37fa74dbb@eucas1p1.samsung.com>
2019-02-12 22:23     ` [PATCH v3 2/7] drivers: devfreq: change devfreq workqueue mechanism Lukasz Luba
2019-02-14  4:11       ` Chanwoo Choi
     [not found]   ` <CGME20190212222433eucas1p264602d67a916c644c7eb5012932fc17a@eucas1p2.samsung.com>
2019-02-12 22:23     ` [PATCH v3 3/7] Kconfig: drivers: devfreq: add default idle polling Lukasz Luba
     [not found]   ` <CGME20190212222434eucas1p134dcdce827df19704c698fd6452b0a06@eucas1p1.samsung.com>
2019-02-12 22:23     ` [PATCH v3 4/7] include: devfreq: add polling_idle_ms to 'profile' Lukasz Luba
2019-02-14  4:51       ` Chanwoo Choi
     [not found]   ` <CGME20190212222436eucas1p21eebc80796406787a2ebf9a84ee5b868@eucas1p2.samsung.com>
2019-02-12 22:23     ` [PATCH v3 5/7] drivers: devfreq: add longer polling interval in idle Lukasz Luba
     [not found]   ` <CGME20190212222437eucas1p198db6fca1f1ba3056d93c57327dd48ed@eucas1p1.samsung.com>
2019-02-12 22:23     ` [PATCH v3 6/7] trace: events: add devfreq trace event file Lukasz Luba
2019-02-12 23:14       ` Steven Rostedt
2019-02-13 13:35         ` Lukasz Luba
2019-02-14  5:01           ` Chanwoo Choi
2019-02-13 13:56       ` Steven Rostedt
2019-02-13 14:37         ` Lukasz Luba
     [not found]   ` <CGME20190212222438eucas1p27e020c2b36f2e5a2188e4df6fb18488b@eucas1p2.samsung.com>
2019-02-12 22:23     ` [PATCH v3 7/7] drivers: devfreq: add tracing for scheduling work Lukasz Luba
2019-02-14  4:57       ` Chanwoo Choi
2019-02-13  0:18   ` [PATCH v3 0/7] drivers: devfreq: fix and optimize workqueue mechanism Chanwoo Choi
2019-02-13 11:14     ` Lukasz Luba
2019-02-13 14:52       ` Lukasz Luba
2019-02-14  0:41       ` Chanwoo Choi
     [not found]   ` <CGME20190212222436eucas1p21eebc80796406787a2ebf9a84ee5b868@epcms1p3>
2019-02-18  4:33     ` [PATCH v3 5/7] drivers: devfreq: add longer polling interval in idle MyungJoo Ham
2019-02-19  8:33       ` Lukasz Luba
     [not found]       ` <CGME20190212222436eucas1p21eebc80796406787a2ebf9a84ee5b868@epcms1p7>
2019-02-21  5:56         ` MyungJoo Ham
2019-02-22 16:03           ` Lukasz Luba

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