From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261535AbVBRWVX (ORCPT ); Fri, 18 Feb 2005 17:21:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261536AbVBRWVX (ORCPT ); Fri, 18 Feb 2005 17:21:23 -0500 Received: from mail.gmx.net ([213.165.64.20]:32478 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S261535AbVBRWVM (ORCPT ); Fri, 18 Feb 2005 17:21:12 -0500 X-Authenticated: #8956447 Subject: Re: [Problem] slow write to dvd-ram since 2.6.7-bk8 From: Droebbel To: Tino Keitel Cc: linux-kernel@vger.kernel.org In-Reply-To: <20050217231048.GA4363@dose.home.local> References: <1108301794.9280.18.camel@localhost.localdomain> <20050213142635.GA2035@animx.eu.org> <20050214085320.GA4910@dose.home.local> <1108376734.9495.8.camel@localhost.localdomain> <20050214105332.GA7163@dose.home.local> <1108379351.9495.22.camel@localhost.localdomain> <20050214111819.GA7691@dose.home.local> <1108590900.7407.11.camel@localhost.localdomain> <1108592965.7407.17.camel@localhost.localdomain> <20050217231048.GA4363@dose.home.local> Content-Type: text/plain Date: Fri, 18 Feb 2005 23:21:10 +0100 Message-Id: <1108765270.14370.22.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.1.5 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fr, 2005-02-18 at 00:10 +0100, Tino Keitel wrote: >On Wed, Feb 16, 2005 at 23:29:24 +0100, Droebbel wrote: >> On Mi, 2005-02-16 at 22:55 +0100, Droebbel wrote: >> >> >The vmscan-dont-reclaim-too-many-pages.patch led to the said reduction >> >of writing speed. I reverse-applied it to 2.6.8.1, where it seems to >> >solve the problem. >> >> Sorry, have to correct that: it seemed to help at my tests with dd >> (write 1G of zeroes to a file). Copying a file with mc still shows >> around 1.4MB/s. Could be worse, but is definitely not ok. It *is* better >> with 2.6.7. > >Here are some numbers with my setup. I always wrote 1 GB of data to the >same DVD-RAM disc (EMTEC), to the device directly and to a fresh ext2 >on >the disc. > >kernel 2.6.10: > >$ time { sudo dd if=/dev/zero of=bigfile bs=64k count=16000 ; sync ; } > >real 32m5.025s > >$ time {sudo dd if=/dev/zero of=/dev/cdrom bs=64k count=16000 ; sync ;} > >real 29m41.980s > >kernel 2.6.7: > >$ time { sudo dd if=/dev/zero of=bigfile bs=64k count=16000 ; sync ; } > >real 13m23.688s > >$ time {sudo dd if=/dev/zero of=/dev/cdrom bs=64k count=16000 ; sync ;} > >real 13m14.609s This is what I get: 2.6.8 to 2.6.10: about 30 min. I think that's clear now. I did not run any mre test with that. 2.6.7 gives less than 10 minutes. Reverse-Patched 2.6.8.1 and 2.6.10 about 9-11 min. But what I think is interesting: Other than with 2.6.7, with my 2.6.10 the result seems to be highly dependent on other io activities. I came to test that when I saw that writing to dvd-ram slowed down when reading from a cdrom at the same time. System disk, cdrom and dvd-ram are connected by buses as independent as possible: hda, hdd and scd0 via on-chip ide2. hdc is inactive and spun down at the times of testing. Some results (same command as yours, but writing to file only): 2.6.8.1 with vmscan-dont-reclaim-too-many-pages.patch and vmscan-scan-sanity.patch reversed: real 9m17.389s real 10m11.271s (run twice) 2.6.10, both patches reversed: real 10m26.374s same kernel, some io and high (but niced) system load by reading from hda and gzipping into /dev/null real 21m46.795s same kernel, some io and low load by reading from cdrom (raw read with dd as well) into /dev/null real 22m11.639s 2.6.7 vanilla, some io and low load by reading from cdrom (raw read with dd as well) into /dev/null real 5m58.092 That's too fast - impossible on 3x media with verification. I'll check that again. But it *really* seemed to be fast. I also hat the impression that my tests with 2.6.10 and 2.6.8.1 were much more promising when run from a rather basic testing system without X, a bit closer to the 2.6.7 results. Haven't got time to check that till monday. All the above results except the 2.6.7 are from Ubuntu (Hoary) Systems with X and Gnome running. Regards David