From: Yuyang Du <yuyang.du@intel.com>
To: bsegall@google.com
Cc: peterz@infradead.org, mingo@kernel.org,
linux-kernel@vger.kernel.org, pjt@google.com,
morten.rasmussen@arm.com, vincent.guittot@linaro.org,
dietmar.eggemann@arm.com, juri.lelli@arm.com
Subject: Re: [PATCH 3/6] sched/fair: Change the variable to hold the number of periods to 32bit integer
Date: Fri, 29 Apr 2016 02:33:47 +0800 [thread overview]
Message-ID: <20160428183347.GB16093@intel.com> (raw)
In-Reply-To: <xm26vb317ib0.fsf@bsegall-linux.mtv.corp.google.com>
On Thu, Apr 28, 2016 at 10:29:55AM -0700, bsegall@google.com wrote:
> Yuyang Du <yuyang.du@intel.com> writes:
>
> > Now a period is about 1ms, so a 32-bit unsigned integer can approximately
> > hold a maximum of 49 (=2^32/1000/3600/24) days, which means it is big enough
> > and 64-bit is needless.
> >
> If a thread sleeps for 49 days and then wakes up this would be wrong...
> but it also would just result in it not being decayed to zero, and even
> then only if it was in a very small window, so it doesn't seem like a
> huge deal if it happens.
Oh, yeah, and we wouldn't know that task is as sleepy as it realy is. :)
next prev parent reply other threads:[~2016-04-29 2:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-28 2:56 [PATCH 0/6] Optimize sched averages computation Yuyang Du
2016-04-28 2:56 ` [PATCH 1/6] sched/fair: Optimize sum computation with a lookup table Yuyang Du
2016-04-28 17:26 ` bsegall
2016-04-28 2:56 ` [PATCH 2/6] sched/fair: Rename variable names for sched averages Yuyang Du
2016-04-28 2:56 ` [PATCH 3/6] sched/fair: Change the variable to hold the number of periods to 32bit integer Yuyang Du
2016-04-28 17:29 ` bsegall
2016-04-28 18:33 ` Yuyang Du [this message]
2016-04-28 2:56 ` [PATCH 4/6] sched/fair: Add __always_inline compiler attribute to __accumulate_sum() Yuyang Du
2016-04-28 2:56 ` [PATCH 5/6] sched/fair: Optimize __update_sched_avg() Yuyang Du
2016-04-28 2:56 ` [PATCH 6/6] documentation: Add scheuler/sched-avg.txt Yuyang Du
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