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From: Peter Zijlstra <>
To: Parth Shah <>
Subject: Re: [RFCv2 4/6] sched/fair: Define core capacity to limit task packing
Date: Wed, 15 May 2019 18:37:52 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Wed, May 15, 2019 at 07:23:20PM +0530, Parth Shah wrote:
> The task packing on a core needs to be bounded based on its capacity. This
> patch defines a new method which acts as a tipping point for task packing.
> The Core capacity is the method which limits task packing above certain
> point. In general, the capacity of a core is defined to be the aggregated
> sum of all the CPUs in the Core.
> Some architectures does not have core capacity linearly increasing with the
> number of threads( or CPUs) in the core. For such cases, architecture
> specific calculations needs to be done to find core capacity.
> The `arch_scale_core_capacity` is currently tuned for `powerpc` arch by
> scaling capacity w.r.t to the number of online SMT in the core.
> The patch provides default handler for other architecture by scaling core
> capacity w.r.t. to the capacity of all the threads in the core.
> ToDo: SMT mode is calculated each time a jitter task wakes up leading to
> redundant decision time which can be eliminated by keeping track of online
> CPUs during hotplug task.

Urgh, we just got rid of capacity for SMT. Also I don't think the above
clearly defines your metric.

  reply	other threads:[~2019-05-15 16:37 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-15 13:53 [RFCv2 0/6] TurboSched: A scheduler for sustaining Turbo Frequencies for longer durations Parth Shah
2019-05-15 13:53 ` [RFCv2 1/6] sched/core: Add manual jitter classification from cgroup interface Parth Shah
2019-05-15 16:29   ` Peter Zijlstra
2019-05-16 16:12     ` Parth Shah
2019-05-15 13:53 ` [RFCv2 2/6] sched: Introduce switch to enable TurboSched mode Parth Shah
2019-05-15 16:30   ` Peter Zijlstra
2019-05-16 16:15     ` Parth Shah
2019-05-15 13:53 ` [RFCv2 3/6] sched/core: Update turbo_sched count only when required Parth Shah
2019-05-15 16:31   ` Peter Zijlstra
2019-05-15 13:53 ` [RFCv2 4/6] sched/fair: Define core capacity to limit task packing Parth Shah
2019-05-15 16:37   ` Peter Zijlstra [this message]
2019-05-15 13:53 ` [RFCv2 5/6] sched/fair: Tune task wake-up logic to pack jitter tasks Parth Shah
2019-05-15 16:43   ` Peter Zijlstra
2019-05-15 13:53 ` [RFCv2 6/6] sched/fair: Bound non idle core search by DIE domain Parth Shah
2019-05-15 16:44   ` Peter Zijlstra
2019-05-16 16:26     ` Parth Shah
2019-05-15 16:48 ` [RFCv2 0/6] TurboSched: A scheduler for sustaining Turbo Frequencies for longer durations Peter Zijlstra
2019-05-16 16:05   ` Parth Shah

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