From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 11 Oct 2000 01:06:11 +0100 (BST) From: Chris Evans Subject: 2.4.0test9 vm: disappointing streaming i/o under load In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Hi, Finally got round to checking out 2.4.0test9. Unfortunately, 2.4.0test9 exhibits poor streaming i/o performance when under a bit of memory pressure. The test is this: boot with mem=32M, log onto GNOME and start xmms playing a big .wav ripped from a CD (this requires 100-200k read i/o per second). Then, I start then kill netscape. I then started a find / and started gnumeric firing up at the same time. Results ======= 2.2 RH7.0: the music skipped maybe twice briefly during the test. 2.4.0test9: music stuttered repeatedly while netscape started. Worse, when firing up gnumeric with the find / on the go, there were big pauses in sound output. On pause was over 5 seconds!!! So not so hot. Could this perhaps be related to the drop_behind magic penalizing streaming i/o pages too much? Perhaps the greater ago on the i/o pages means that when there is a little memory pressure, they are getting thrown out the page cache before the app (xmms) gets a chance to use them! Might it be useful for me to try pre10-1, I note it has more "balancing fixes". Cheers Chris -- 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/