From: Vincent Guittot <vincent.guittot@linaro.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Brendan Jackman <brendan.jackman@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>
Subject: Re: [RFC PATCH 2/5] sched: Add NOHZ_STATS_KICK
Date: Fri, 22 Dec 2017 09:04:35 +0100 [thread overview]
Message-ID: <CAKfTPtCXuHzoFMsL7CwKzkqi0sDbhaOTKjdqPrZfdkC_7g=jkg@mail.gmail.com> (raw)
In-Reply-To: <20171222075643.zrdsayvcpovysnre@hirez.programming.kicks-ass.net>
On 22 December 2017 at 08:56, Peter Zijlstra <peterz@infradead.org> wrote:
> On Thu, Dec 21, 2017 at 05:23:27PM +0100, Vincent Guittot wrote:
>> Hi Peter,
>>
>> I think that part of the proposal is missing.
>>
>> One goal of the patchset was to kick an update of the stats of idle
>> cpu when a task wake up on a cpu but the statistic has not been
>> updated for a while.
>>
>> That's why there where a call to nohz_kick_needed in the proposal to
>> kick ilb but only for updating blocked load and not a full idle load
>> balance
>>
>> I can't find this call any more in your patchset
>
> Yeah, I took it out because it didn't make sense to me. If you're waking
> to a stale CPU, you're too late.
I agree that's it's too late for the current wake up but that's the
trade off with delaying the wake up until all blocked load has been
updated.
>
next prev parent reply other threads:[~2017-12-22 8:04 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-21 10:21 [RFC PATCH 0/5] sched: On remote stats updates Peter Zijlstra
2017-12-21 10:21 ` [RFC PATCH 1/5] sched: Convert nohz_flags to atomic_t Peter Zijlstra
2017-12-21 10:21 ` [RFC PATCH 2/5] sched: Add NOHZ_STATS_KICK Peter Zijlstra
2017-12-21 16:23 ` Vincent Guittot
2017-12-21 16:56 ` Vincent Guittot
2017-12-22 7:59 ` Peter Zijlstra
2017-12-22 8:05 ` Vincent Guittot
2017-12-22 8:29 ` Peter Zijlstra
2017-12-22 9:12 ` Peter Zijlstra
2017-12-22 14:31 ` Peter Zijlstra
2017-12-22 14:34 ` Vincent Guittot
2017-12-22 14:32 ` Vincent Guittot
2017-12-22 18:56 ` Peter Zijlstra
2017-12-22 20:42 ` Peter Zijlstra
2018-01-02 15:44 ` Morten Rasmussen
2018-01-15 9:43 ` Peter Zijlstra
2018-01-18 10:32 ` Morten Rasmussen
2018-01-03 9:16 ` Vincent Guittot
2018-01-15 8:26 ` Vincent Guittot
2018-01-18 10:38 ` Morten Rasmussen
2018-01-24 8:25 ` Vincent Guittot
2018-01-29 18:43 ` Dietmar Eggemann
2018-01-30 8:00 ` Vincent Guittot
2018-01-29 19:31 ` Valentin Schneider
2018-01-30 8:32 ` Vincent Guittot
2018-01-30 11:41 ` Valentin Schneider
2018-01-30 13:05 ` Vincent Guittot
2018-02-05 22:18 ` Valentin Schneider
2018-02-06 9:22 ` Vincent Guittot
2018-02-01 18:16 ` Peter Zijlstra
2018-02-01 16:57 ` Peter Zijlstra
2018-02-01 17:26 ` Vincent Guittot
2018-02-01 18:10 ` Peter Zijlstra
2018-02-01 19:11 ` Vincent Guittot
2018-02-06 8:32 ` [PATCH 1/3] sched: Stop nohz stats when decayed Vincent Guittot
2018-02-06 8:32 ` [PATCH 2/3] sched: reduce the periodic update duration Vincent Guittot
2018-02-06 8:32 ` [PATCH 3/3] sched: update blocked load when newly idle Vincent Guittot
2018-02-06 14:32 ` Valentin Schneider
2018-02-06 16:17 ` Vincent Guittot
2018-02-06 16:32 ` Valentin Schneider
2018-02-06 8:55 ` [PATCH 1/3] sched: Stop nohz stats when decayed Vincent Guittot
2018-02-06 14:16 ` Valentin Schneider
2018-02-06 14:31 ` Vincent Guittot
2018-02-01 16:55 ` [RFC PATCH 2/5] sched: Add NOHZ_STATS_KICK Peter Zijlstra
2018-01-22 9:40 ` Dietmar Eggemann
2018-01-22 10:23 ` Vincent Guittot
2018-02-01 16:52 ` Peter Zijlstra
2018-02-01 17:25 ` Vincent Guittot
2017-12-22 7:56 ` Peter Zijlstra
2017-12-22 8:04 ` Vincent Guittot [this message]
2017-12-21 10:21 ` [RFC PATCH 3/5] sched: Restructure nohz_balance_kick Peter Zijlstra
2017-12-21 10:21 ` [RFC PATCH 4/5] sched: Add nohz stats balancing Peter Zijlstra
2017-12-21 10:21 ` [RFC PATCH 5/5] sched: Update blocked load from NEWIDLE Peter Zijlstra
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