linux-kernel - Re: [PATCH RFC] sched/deadline: Use the revised wakeup rule for suspending constrained dl tasks

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]

Message-ID: <5fd0446b-0c5c-ce82-7e18-c56140e1a83b@redhat.com>
Date:   Mon, 24 Apr 2017 20:51:46 +0200
From:   Daniel Bristot de Oliveira <bristot@...hat.com>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Xunlei Pang <xpang@...hat.com>,
        Juri Lelli <juri.lelli@....com>,
        Luca Abeni <luca.abeni@...tannapisa.it>,
        Tommaso Cucinotta <tommaso.cucinotta@...up.it>,
        Romulo Silva de Oliveira <romulo.deoliveira@...c.br>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC] sched/deadline: Use the revised wakeup rule for
 suspending constrained dl tasks

On 04/24/2017 07:00 PM, Steven Rostedt wrote:
>> +static void
>> +update_dl_revised_wakeup(struct sched_dl_entity *dl_se, struct rq *rq)
>> +{
>> +	u64 density = div64_u64(dl_se->dl_runtime << 20, dl_se->dl_deadline);
> Hmm, dl_runtime and dl_deadline don't get updated that often. Can't we
> simply keep a static dl_se->dl_density, and update it when dl_runtime
> or dl_deadline get updated? That would get rid of the divide in the
> middle of a wake up call.

Yeah, I agree! Juri also pointed in the same direction, I will add it in
the possible next version ;-).

Thanks for the feedback!

-- Daniel