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From: Zhaoyang Huang <zhaoyang.huang@linaro.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	mingo@redhat.com, peterz@infradead.org,
	"Zhaoyang Huang (黄朝阳)" <zhaoyang.huang@spreadtrum.com>
Subject: Re: [RESEND PATCH v2 2/2] power/idle: enhance the precision of sleep_length
Date: Fri, 17 Jun 2016 19:18:30 +0800	[thread overview]
Message-ID: <CAN2waFuETjxzRwST_EGY4GhxFUZZsOPkysrcBsKCSmcp5hV+UQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1606171125460.5839@nanos>

On 17 June 2016 at 17:27, Thomas Gleixner <tglx@linutronix.de> wrote:
> On Fri, 17 Jun 2016, Zhaoyang Huang wrote:
>> There should be a gap between tick_nohz_idle_enter and
>> tick_nohz_get_sleep_length when idle, which will cause the
>> sleep_length is not very precised. Change it in this patch.
>
> What kind of imprecision are we talking about? Seconds, nanoseconds or
> lightyears?
>
> Your changelog lacks any form of useful information.
>
> Thanks,
>
>         tglx
>
>
sorry for the confusion. The imprecision can be caused by, for
example, the callback function registered for CPU_PM_ENTER, which may
consume a period of time within the 'idle' time. Besides, I also
wonder why not calc the 'sleep_length' in the
tick_nohz_get_sleep_length?  This value is calculated at very
beginning of the idle in current approach.

  reply	other threads:[~2016-06-17 11:18 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-17  9:13 [RESEND PATCH v2 1/2] power/cpuidle: enhance the precision of state select Zhaoyang Huang
2016-06-17  9:13 ` [RESEND PATCH v2 2/2] power/idle: enhance the precision of sleep_length Zhaoyang Huang
2016-06-17  9:27   ` Thomas Gleixner
2016-06-17 11:18     ` Zhaoyang Huang [this message]
2016-06-17 11:50       ` Thomas Gleixner
2016-06-20  1:14         ` Zhaoyang Huang
2016-06-22  3:01           ` Zhaoyang Huang
2016-06-23  7:01             ` Thomas Gleixner
2016-06-23  7:26               ` Zhaoyang Huang
2016-06-23  8:18                 ` Thomas Gleixner
2016-06-23  8:34                   ` Zhaoyang Huang
2016-06-23  8:35                     ` Thomas Gleixner
2016-06-23  8:45                       ` Zhaoyang Huang
2016-06-23 10:16                         ` Thomas Gleixner
2016-06-25  1:09 ` [RESEND PATCH v2 1/2] power/cpuidle: enhance the precision of state select Rafael J. Wysocki
2016-06-27  1:13   ` Zhaoyang Huang

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