Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761251AbXEaJ3A (ORCPT ); Thu, 31 May 2007 05:29:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760702AbXEaJ2a (ORCPT ); Thu, 31 May 2007 05:28:30 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:49807 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760855AbXEaJ23 (ORCPT ); Thu, 31 May 2007 05:28:29 -0400 Date: Thu, 31 May 2007 15:06:22 +0530 From: Srivatsa Vaddagiri To: William Lee Irwin III Cc: Nick Piggin , ckrm-tech@lists.sourceforge.net, efault@gmx.de, Peter Williams , tingy@cs.umass.edu, linux-kernel@vger.kernel.org, kernel@kolivas.org, tong.n.li@intel.com, containers@lists.osdl.org, Ingo Molnar , torvalds@linux-foundation.org, akpm@linux-foundation.org, Guillaume Chazarain Subject: Re: [ckrm-tech] [RFC] [PATCH 0/3] Add group fairness to CFS Message-ID: <20070531093622.GB9826@in.ibm.com> Reply-To: vatsa@in.ibm.com References: <20070526154112.GA31925@holomorphy.com> <20070530171405.GA21062@in.ibm.com> <20070530201359.GD6909@holomorphy.com> <20070531032657.GA823@in.ibm.com> <20070531040926.GH6909@holomorphy.com> <20070531054828.GB663@in.ibm.com> <20070531063647.GC15426@holomorphy.com> <20070531083353.GF663@in.ibm.com> <20070531085600.GA9826@in.ibm.com> <20070531091534.GK6909@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070531091534.GK6909@holomorphy.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1708 Lines: 38 On Thu, May 31, 2007 at 02:15:34AM -0700, William Lee Irwin III wrote: > Yes, the larger number of schedulable entities and hence slower > convergence to groupwise weightings is a disadvantage of the flattening. > A hybrid scheme seems reasonable enough. Cool! This puts me back on track to implement hierarchical scheduling in CFS :) Once this is done and once I can get containers running on a box, I will experiment with the flattening trick for user and process levels inside containers. Thanks for your feedback so far! > Ideally one would chop the > hierarchy in pieces so that n levels of hierarchy become k levels of n/k > weight-flattened hierarchies for this sort of attack to be most effective > (at least assuming similar branching factors at all levels of hierarchy > and sufficient depth to the hierarchy to make it meaningful) but this is > awkward to do. Peeling off the outermost container or whichever level is > deemed most important in terms of accuracy of aggregate enforcement as > a hierarchical scheduler is a practical compromise. > > Hybrid schemes will still incur the difficulties of hierarchical > scheduling, but they're by no means insurmountable. Sadly, only > complete flattening yields the simplifications that make task group > weighting enforcement orthogonal to load balancing and the like. The > scheme I described for global nice number behavior is also not readily > adaptable to hybrid schemes. -- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/