From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Message-Id: <200003270642.HAA07740@flint.arm.linux.org.uk> Subject: Re: [PATCH] Re: kswapd Date: Mon, 27 Mar 2000 07:42:32 +0100 (BST) In-Reply-To: <200003270239.SAA97539@google.engr.sgi.com> from "Kanoj Sarcar" at Mar 26, 2000 06:39:14 PM MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Kanoj Sarcar Cc: riel@nl.linux.org, linux-mm@kvack.org, linux-kernel@vger.rutgers.edu List-ID: Kanoj Sarcar writes: > > Without my patch kswapd uses between 50 and 70% CPU time > > in a particular workload. Now it uses between 3 and 5%. > > Can you explain how this is happening? I can see that in your patch, > kswapd does not go thru the loop if need_resched is set, but with > a single node, 3 zones, I would find it hard to explain such a > difference. kswapd was running until it had a quantum, whether or not it had to free any more pages. > > Oh, and the latency problem probably has been fixed too... > > What latency problem? I still believe that the pre3 code is doing > the right thing, assuming 2.3.43 was doing the right thing. Check out the linux-kernel archives, specifically for my mails about NFS/sound problems - it is not good for processes (eg, rpciod) to be starved of CPU time up to 200-400ms. It was basically impossible to play mp3s without the playback basically "stopping" for that period. (without the patch in, I see kswapd using 200ms-400ms. With the patch in, it only uses >10ms very very rarely). _____ |_____| ------------------------------------------------- ---+---+- | | Russell King rmk@arm.linux.org.uk --- --- | | | | http://www.arm.linux.org.uk/~rmk/aboutme.html / / | | +-+-+ --- -+- / | THE developer of ARM Linux |+| /|\ / | | | --- | +-+-+ ------------------------------------------------- /\\\ | -- 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.eu.org/Linux-MM/