Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 15 Oct 2001 22:15:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 15 Oct 2001 22:14:50 -0400 Received: from [209.195.52.30] ([209.195.52.30]:27938 "HELO [209.195.52.30]") by vger.kernel.org with SMTP id ; Mon, 15 Oct 2001 22:14:29 -0400 From: David Lang To: Patrick McFarland Cc: linux-kernel@vger.kernel.org Date: Mon, 15 Oct 2001 17:53:32 -0700 (PDT) Subject: Re: VM In-Reply-To: <20011015211216.A1314@localhost> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org from an interested bystander here's how I see it much of the time the -ac VM is better, but sometimes it is MUCH worse. It's performance can vary substantually even while running the same test. the linux VM may not be as fast in some cases, but it is far more predictable and repeatable, and doesn't have the same horrible 'worst case' performance that has been the bane of the 2.4 kernels. say for the sake of argument that the linus VM is only 80% as good as the -ac VM. but the -ac VM has pathalogical conditions that hit is 5% of the time (both numbers out of thin air, I'm sure that aa would argue that it's better then the 80% and Rik would argue that it's less then 5% :-) we're late in the 2.4 series, stability and predictability is better then raw performance. the 5% pathalogical problem is bad enough to make that VM unsuatable for many machines (and worse the conditions that trigger it aren't well understood making it untrustworthy for a much larger group of machines) while the slight performance hit on the 80% as good is much easier to deal with (buy a faster disk or more ram) I have been impressed by the repeatability shown by the linus VM system and have just been waiting for the last of the gotchas to be hammered out before switching my production machines from 2.4.5 to a newer kernel. David Lang On Mon, 15 Oct 2001, Patrick McFarland wrote: > Date: Mon, 15 Oct 2001 21:12:18 -0400 > From: Patrick McFarland > To: linux-kernel@vger.kernel.org > Subject: VM > > Linus, this question is really to you... > > Why is the simple vm system still in place on the linus tree? I would think the smart vm system in the ac tree would be better suited to .. oh.. say .. everything. (The potential for less swapping is _always better_) > > -- > Patrick "Diablo-D3" McFarland || unknown@panax.com > - > 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/ > - 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/