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Subject: Re: Question about group scheduler cpu shares
From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: Gaurav Poothia <gaurav.poothia@gmail.com>
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Date: Fri, 22 Jul 2016 06:19:13 +0200
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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