linux-kernel - Re: [ANNOUNCE/RFC] Really Simple Really Fair Scheduler

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: <Pine.LNX.4.64.0709032140140.1817@scrub.home>
Date:	Mon, 3 Sep 2007 21:55:20 +0200 (CEST)
From:	Roman Zippel <zippel@...ux-m68k.org>
To:	Ingo Molnar <mingo@...e.hu>
cc:	linux-kernel@...r.kernel.org, peterz@...radead.org,
	Mike Galbraith <efault@....de>
Subject: Re: [ANNOUNCE/RFC] Really Simple Really Fair Scheduler

Hi,

On Mon, 3 Sep 2007, Ingo Molnar wrote:

> My next question then is about this code of yours in the wakeup path:
> 
>  +static void
>  +enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
>  +{
>  +       kclock_t min_time;
>  +
>  +       verify_queue(cfs_rq, cfs_rq->curr != se, se);
>  +       min_time = get_time_avg(cfs_rq) - se->req_weight_inv;
>  +       if ((kclock_t)(se->time_norm - min_time) < 0)
>  +               se->time_norm = min_time;
> 
> why do you only use the "min_time" if the pre-sleep time_norm is smaller 
> than the min_time? Here 'min_time' is close to the current average. 

It's a variation of the sleeper bonus. Let's assume two running tasks 
which have been running for 95ms and 105ms and a time slice of 10ms, the 
average is thus 100ms. If the new task has been sleeping for a while it 
starts at 90ms, if the task had been running lately it doesn't get this 
bonus again.

> Shouldnt here the woken up task be set to the average time, like i did 
> it in the crude prototype:
> 
> +               se->exec_runtime = avg_exec_runtime(cfs_rq);

That would be equivalent to simply clearing wait_runtime in CFS.

bye, Roman
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/