lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Wed, 15 May 2019 18:37:52 +0200
From:   Peter Zijlstra <>
To:     Parth Shah <>
Subject: Re: [RFCv2 4/6] sched/fair: Define core capacity to limit task

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.

Powered by blists - more mailing lists