linux-kernel - Re: [PATCH] sched/fair: Do not decay new task load on first enqueue

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:   Sun, 9 Oct 2016 11:39:27 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     Matt Fleming <matt@...eblueprint.co.uk>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Mike Galbraith <umgwanakikbuti@...il.com>,
        Yuyang Du <yuyang.du@...el.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>
Subject: Re: [PATCH] sched/fair: Do not decay new task load on first enqueue

2016-09-29 3:37 GMT+08:00 Matt Fleming <matt@...eblueprint.co.uk>:
> On Wed, 28 Sep, at 12:14:22PM, Peter Zijlstra wrote:
>>
>> Which suggests we do something like the below (not compile tested or
>> anything, also I ran out of tea again).
>
> I'm away on FTO right now. I can test this when I return on Friday.
>
> Funnily enough, I now remember that I already sent a fix for the
> missing update_rq_clock() in post_init_entity_util_avg(), but didn't
> apply it when chasing this hackbench regression (oops),
>
>   https://lkml.kernel.org/r/20160921133813.31976-3-matt@codeblueprint.co.uk

The difference between this patch and Peterz's is your patch have a
delta since activate_task()->enqueue_task() does do update_rq_clock(),
so why don't have the delta will cause low cpu machines (4 or 8) to
regress against your another reply in this thread?

Regards,
Wanpeng Li