linux-kernel - Re: Question about group scheduler cpu shares

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] [day] [month] [year] [list]

Date:	Fri, 22 Jul 2016 06:19:13 +0200
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Gaurav Poothia <gaurav.poothia@...il.com>
Cc:	linux-kernel@...r.kernel.org, peterz@...radead.org,
	mingo@...hat.com
Subject: Re: Question about group scheduler cpu shares

On Thu, 2016-07-21 at 20:24 -0700, Gaurav Poothia wrote:

(top posting.. naught naughty;)

> 1.What is the function that translates from various nice levels to
> weight i.e. nice(0) == 1024 how to translate for other levels

If you rummage around in kernel/sched, you'll find this table:

const int sched_prio_to_weight[40] = {
 /* -20 */     88761,     71755,     56483,     46273,     36291,
 /* -15 */     29154,     23254,     18705,     14949,     11916,
 /* -10 */      9548,      7620,      6100,      4904,      3906,
 /*  -5 */      3121,      2501,      1991,      1586,      1277,
 /*   0 */      1024,       820,       655,       526,       423,
 /*   5 */       335,       272,       215,       172,       137,
 /*  10 */       110,        87,        70,        56,        45,
 /*  15 */        36,        29,        23,        18,        15,
};

> 2.How does that work when an interior node has multiple tasks? So if I
> added tasks E and F with difference nice levels to Group 1 task list
> how would the math work?

The math works the same as if you were adding task groups.  An entity
is an entity is an entity...

	-Mike