From: Valentin Schneider <valentin.schneider@arm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@redhat.com, peterz@infradead.org,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com
Subject: Re: [RFC PATCH 4/7] sched/fair: Dissociate wakeup decisions from SD flag value
Date: Wed, 11 Dec 2019 16:53:22 +0000 [thread overview]
Message-ID: <26381004-06f5-a006-1e30-49e5e3d4f8d8@arm.com> (raw)
In-Reply-To: <20191211164401.5013-5-valentin.schneider@arm.com>
On 11/12/2019 16:43, Valentin Schneider wrote:
> @@ -6396,9 +6396,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags)
> if (unlikely(sd)) {
> /* Slow path */
> new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag);
> - } else if (sd_flag & SD_BALANCE_WAKE) { /* XXX always ? */
> + } else if (wake_flags & WF_TTWU) { /* XXX always ? */
While I'm at it, Dietmar pointed out to me that this is only really
relevant to forkees and execees when a NULL domain is attached to the CPU
(since sd_init() unconditionally sets SD_BALANCE_{FORK, EXEC}). So this
only makes a difference when the SD hierarchy hasn't been built / is being
rebuilt, or when cpusets are involved.
So perhaps we could make that an unconditional else, or make forkees/execees
bail out earlier.
> /* Fast path */
> -
> new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
>
> if (want_affine)
>
next prev parent reply other threads:[~2019-12-11 16:53 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 16:43 [RFC PATCH 0/7] sched: Streamline select_task_rq() & select_task_rq_fair() Valentin Schneider
2019-12-11 16:43 ` [RFC PATCH 1/7] sched: Add WF_TTWU, WF_EXEC wakeup flags Valentin Schneider
2019-12-11 16:43 ` [RFC PATCH 2/7] sched: Kill select_task_rq()'s sd_flag parameter Valentin Schneider
2019-12-11 16:43 ` [RFC PATCH 3/7] sched/fair: find_idlest_group(): Remove unused " Valentin Schneider
2019-12-11 16:43 ` [RFC PATCH 4/7] sched/fair: Dissociate wakeup decisions from SD flag value Valentin Schneider
2019-12-11 16:53 ` Valentin Schneider [this message]
2019-12-11 16:43 ` [RFC PATCH 5/7] sched/topology: Make {lowest/highest}_flag_domain() work with > 1 flags Valentin Schneider
2019-12-11 16:44 ` [RFC PATCH 6/7] sched/fair: Split select_task_rq_fair want_affine logic Valentin Schneider
2019-12-11 16:44 ` [RFC PATCH 7/7] sched/topology: Define and use shortcut pointers for wakeup sd_flag scan Valentin Schneider
2020-01-06 8:10 ` [RFC PATCH 0/7] sched: Streamline select_task_rq() & select_task_rq_fair() Peter Zijlstra
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