From: Viresh Kumar <viresh.kumar@linaro.org>
To: Yunhong Jiang <yunhong.jiang@linux.intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] timer: Lazily wakup nohz CPU when adding new timer.
Date: Fri, 23 Oct 2015 07:49:51 +0530 [thread overview]
Message-ID: <20151023021951.GP3897@ubuntu> (raw)
In-Reply-To: <20151022214003.GA22993@jnakajim-build>
On 22-10-15, 14:40, Yunhong Jiang wrote:
> A naive question is, why it's sure a tick will happen when the tickless
> processor is in idle?
How do you get this impression? I don't think anyone has said that.
We are talking about deferrable timers, which by design are only
required if the target CPU is not-idle. If it is idle, then the timer
isn't required to be serviced until the CPU wakes up. And the CPU can
take whatever time it wants to wake up again.
> Is it because scheduler load balance is sure to send a
> tick to the processor in future?
No. We aren't expecting the CPU to wake up any time soon. Just ignore
the deferrable timer.
--
viresh
next prev parent reply other threads:[~2015-10-23 2:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-28 18:48 [PATCH] timer: Lazily wakup nohz CPU when adding new timer Yunhong Jiang
2015-10-05 20:51 ` Yunhong Jiang
2015-10-11 18:12 ` Thomas Gleixner
2015-10-20 22:47 ` Yunhong Jiang
2015-10-21 10:46 ` Viresh Kumar
2015-10-22 21:40 ` Yunhong Jiang
2015-10-23 2:19 ` Viresh Kumar [this message]
2015-10-23 22:10 ` Yunhong Jiang
2015-10-24 3:20 ` Viresh Kumar
2015-10-26 16:26 ` Yunhong Jiang
2015-10-27 15:11 ` Frederic Weisbecker
2015-11-13 16:13 ` Frederic Weisbecker
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