linux-kernel - Re: [RFC] Fair-user 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: <45BA4B57.1070604@nortel.com>
Date:	Fri, 26 Jan 2007 12:41:27 -0600
From:	"Chris Friesen" <cfriesen@...tel.com>
To:	vatsa@...ibm.com
CC:	riel@...hat.com, Ingo Molnar <mingo@...e.hu>,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Andrew Morton <akpm@...l.org>, linux-kernel@...r.kernel.org
Subject: Re: [RFC] Fair-user scheduler

Srivatsa Vaddagiri wrote:
> Current Linux CPU scheduler doesnt recognize process aggregates while
> allocating bandwidth. As a result of this, an user could simply spawn large 
> number of processes and get more bandwidth than others.
> 
> Here's a patch that provides fair allocation for all users in a system.
> 
> Some benchmark numbers with and without the patch applied follows:
> 
> 
> 		 	user "vatsa"		    user "guest"
> 		    (make -s -j4 bzImage)      (make -s -j20 bzImage)
> 
> 2.6.20-rc5		472.07s (real)		   257.48s (real)
> 2.6.20-rc5+fairsched	766.74s (real)		   766.73s (real)

As Kirill brought up, why does it take so much more time?  Are you 
thrashing the cache?

> 	- breaks O(1) (ouch!)
> 		Best way to avoid this is to split runqueue to be per-user and
> 		per-cpu, which I have not implemented to keep the patch simple.

Presumably this would be made generic, as in per-"group" rather than per 
user?

> 	- Fairsched aware SMP load balance NOT addressed (yet)

This is kind of important, no?

Chris
-
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/