linux-kernel - Re: [RFC 0/2] Optimize the idle CPU search

lists.openwall.net		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 linux-hardening linux-cve-announce 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:   Tue, 9 Jul 2019 05:38:10 +0530
From:   Subhra Mazumdar <subhra.mazumdar@...cle.com>
To:     Parth Shah <parth@...ux.ibm.com>, linux-kernel@...r.kernel.org
Cc:     peterz@...radead.org, mingo@...hat.com, vincent.guittot@...aro.org
Subject: Re: [RFC 0/2] Optimize the idle CPU search


On 7/8/19 10:24 AM, Parth Shah wrote:
> When searching for an idle_sibling, scheduler first iterates to search for
> an idle core and then for an idle CPU. By maintaining the idle CPU mask
> while iterating through idle cores, we can mark non-idle CPUs for which
> idle CPU search would not have to iterate through again. This is especially
> true in a moderately load system
>
> Optimize idle CPUs search by marking already found non idle CPUs during
> idle core search. This reduces iteration count when searching for idle
> CPUs, resulting in lower iteration count.
>
I believe this can co-exist with latency-nice? We can derive the 'nr' in
select_idle_cpu from latency-nice and use the new mask to iterate.