linux-kernel - [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-next>] [day] [month] [year] [list]

Message-ID: <20070126060142.GA2487@in.ibm.com>
Date:	Fri, 26 Jan 2007 11:31:42 +0530
From:	Srivatsa Vaddagiri <vatsa@...ibm.com>
To:	riel@...hat.com, Ingo Molnar <mingo@...e.hu>,
	Nick Piggin <nickpiggin@...oo.com.au>,
	Andrew Morton <akpm@...l.org>
Cc:	linux-kernel@...r.kernel.org
Subject: [RFC] Fair-user scheduler

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)


(Numbers taken on a 2way Intel x86_64 box)

Eventually something like this can be extended to do weighted fair share
scheduling for:

	- KVM
	- containers
	- resource management

Salient features of the patch:

	- Based on Ingo's RTLIMIT_RT_CPU patch [1]. Primary difference between 
	  RTLIMIT_RT_CPU patch and this one is that this patch handles 
	  starvation of lower priority tasks in a group and also accounting
	  is token based (rather than decaying avg).

	- Retains existing one-runqueue-per-cpu design

	- 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.

	- Fairsched aware SMP load balance NOT addressed (yet)

Comments/flames wellcome!


References:

1. http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.11-rc2/2.6.11-rc2-mm2/broken-out/rlimit_rt_cpu.patch

-- 
Regards,
vatsa
-
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/