From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Stoffel MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15137.15472.264539.290588@gargle.gargle.HOWL> Date: Fri, 8 Jun 2001 16:58:24 -0400 Subject: Re: VM Report was:Re: Break 2.4 VM in five easy steps In-Reply-To: References: <15137.3796.287765.4809@gargle.gargle.HOWL> Sender: owner-linux-mm@kvack.org Return-Path: To: Marcelo Tosatti Cc: John Stoffel , Mike Galbraith , Tobias Ringstrom , Jonathan Morton , Shane Nay , "Dr S.M. Huen" , Sean Hunter , Xavier Bestel , lkml , linux-mm@kvack.org List-ID: Marcelo> Now the stock kernel gives us crappy interactivity compared Marcelo> to my patch. (Note: my patch still does not gives me the Marcelo> interactivity I want under high VM loads, but I hope to get Marcelo> there soon). This raises the important question, how can we objectively measure interactive response in the kernel and relate it to the user's perceived interactive response? If we could come up with some sort of testing system that would show us this, it would help alot, since we could just have people run tests in a more automatic and repeatable manner. And I think it would also help us automatically tune the Kernel, since it would have a knowledge of it's own performance. There is the problem in terms of some people want pure interactive performance, while others are looking for throughput over all else, but those are both extremes of the spectrum. Though I suspect raw throughput is the less wanted (in terms of numbers of systems) than keeping interactive response good during VM pressure. I have zero knowledge of how we could do this, but giving the kernel some counters, even if only for use during debugging runs, which would give us some objective feedback on performance would be a big win. Having people just send in reports of "I ran X,Y,Z and it was slow" doesn't help us, since it's so hard to re-create their environment so you can run tests against it. Anyway, enjoy the weekend all. John John Stoffel - Senior Unix Systems Administrator - Lucent Technologies stoffel@lucent.com - http://www.lucent.com - 978-952-7548 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/