Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 11 Jul 2001 01:04:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 11 Jul 2001 01:04:04 -0400 Received: from wren.rentec.com ([192.5.35.106]:55477 "EHLO ram.rentec.com") by vger.kernel.org with ESMTP id ; Wed, 11 Jul 2001 01:03:52 -0400 Message-ID: <3B4BEC57.7000509@rentec.com> Date: Wed, 11 Jul 2001 01:04:07 -0500 From: Dirk Wetter User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:0.9.2+) Gecko/20010707 X-Accept-Language: en-us MIME-Version: 1.0 To: Rik van Riel CC: Wayne Whitney , linux-kernel@vger.kernel.org Subject: Re: dead mem pages In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Filter-Version: 1.3 (wren) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rik, thx for your answer. :) Rik van Riel wrote: >On Tue, 10 Jul 2001, Dirk Wetter wrote: > >>>It would be good to know what these 2.8GB of cached pages are. >>> >>believe me, i would like to know too where all the $$$ memory >>went to. ;-) >> > >Most likely swap cache, that means it is the memory from your >simulations, just removed from the page tables and put in the >swap cache. > but why was the machine actually swapping then? sar definetely showed swap and disk activity as the applications started. >>>Again on a general note, the 2.4 kernel's VM is new and hence not fully >>>mature. So the short and unhelpful answer to your query is probably that >>>the current VM system is not well tuned for your workload (4.3GB of memory >>>hungry simulations on a 4GB machine). >>> >>concerning the maturity that's also the answer i got from the kernel >>guru's at last USENIX in boston. but ihmo it *should* become soon >>better for the future if Linux intends to become bigger in the server >>business. (my $0.02) >> > >It'll get better as soon as we have the time, for 2.4.7 >the VM statistics have already improved a bit so people >are no longer fooled by large "cached" figures ;) > Rik (and Wayne): it's *not only* the statistics. they were swapping like crazy. the only thing the machines were responding immediately to were icmp packets. no tcp/udp. keystrokes on the console were echoed 2 minutes after i typed the command in. with some patience i managed to execute "top" i caught pictures were kswapd was in the first line having 99% or so of one CPU and the load was between 20 and 30. > >Actual improvements to the code, if needed at all, will >come with time ... more than $0.02 will get you ;) > not that i don't appreciate very much your work, but i had to learn that improvements are needed: we could swap our 4GB machines to death just by submitting jobs in the size of the ~physical memory to them. but i don't have any doubts that you guys will manage to do neccessary changes:-) i do the profile tests Marcelo suggested (thx) and come back with some numbers. tschuess :-) ~dirkw - 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/