Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 21 Jan 2002 17:25:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 21 Jan 2002 17:24:55 -0500 Received: from waldorf.cs.uni-dortmund.de ([129.217.4.42]:44443 "EHLO waldorf.cs.uni-dortmund.de") by vger.kernel.org with ESMTP id ; Mon, 21 Jan 2002 17:24:33 -0500 Message-Id: <200201212218.g0LMI8BQ002150@tigger.cs.uni-dortmund.de> To: Robert Love cc: linux-kernel@vger.kernel.org Subject: Re: [2.4.17/18pre] VM and swap - it's really unusable In-Reply-To: Message from Robert Love of "21 Jan 2002 16:22:58 EST." <1011648179.850.473.camel@phantasy> Date: Mon, 21 Jan 2002 23:18:08 +0100 From: Horst von Brand Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Robert Love said: [...] > It doesn't have to run mostly in the kernel. It just has to be in the > kernel when the I/O-bound tasks awakes. Further, there are plenty of > what we consider CPU-bound tasks that are interactive and/or > graphics-oriented and this adds much to their time in the kernel. Look, I don't know about you, but system (kernel) tieme around here is rarely very high as a %. Perhaps 5% could be called "typical". And it is during those 5% (i.e., something like 5% of the time) any of this stuff will make a difference at all. This will be _hard_ to "feel" (if it is possible to feel at all). For the mostly positive (subjective) responses you see, there is something called "psycology", which would predict that for _exactly_ the same "feel" (whatever that may be) somebody who just made an effort downloading patches, applying them, reconfiguring ad building a kernel "to make it feel better" _will_ feel it better. I.e., nobody wants to have to say "Okay, lots of work down the drain". Besides, those who see no difference will shut up, those that delude themselves most will be vocal about it. There was a famous experiment in determining productivity of people under various circumstances. Whatever they changed, the productivity went up. They finally had to conclude their results weren't due to the environmental changes, but to the fact that the subjects felt important (and motivated). Something similar might be happening here. I'm not saying it _is_ like this, but as long as there are no reproducible ways to put numbers to the "feel", and make controlled experiments, no one will know for sure. > In a given period of time, [...] Yes, yes, we all know the theory, and it is obviously true. Question is just, _how much_ is the change? Is it large enough to compensate for the pain it causes? [...] > While we certainly need tangible empirical benefits, users finding their > desktop experience smoother and thus more enjoyable is just about the > best thing we can ask for. It just isn't enough justification for wholesale redesign on basic assumptions in the kernel, sorry. -- Horst von Brand http://counter.li.org # 22616 - 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/