Package: linux-image-2.6.32-5-686 Version: 2.6.32-35squeeze2jba Severity: normal
After adding a ssd (OCZ Vertex Plus 60GB) to my squeeze system (debian kernel 2.6.32) I was disappointed about its performance, as it was advertised with 185 MB/s. /dev/sdb: Timing buffered disk reads: 214 MB in 3.01 seconds = 71.04 MB/sec However, when running recent knoppix (kernel 3.0.4) I got the expected performance: /dev/sdb: Timing buffered disk reads: 490 MB in 3.00 seconds = 163.07 MB/sec After googling, I found that this has been reported before: http://www.archivum.info/linux-...@vger.kernel.org/2010-02/00243/bad-performance-with-SSD-since-kernel-version-2.6.32.html It seems that early versions of kernel 2.6.32 have a bug that results in bad performance of some ssds (maybe all, at least the 'OCZ Vertex Plus 60GB' and the 'Super Talent Ultradrive GX MLC 64GB'). Reverting the patch as described in the discussion solved the problem for me. I now have the desired performance. Thus, I would suggest to revert the patch "block: improve queue_should_plug() by looking at IO depths" in kernel 2.6.32 for squeeze in order to get full ssd performance. I think the bugfix is important as an increasing number of users havs ssds and the bug more or less breaks ssd performance in squeeze. Juergen -- System Information: Debian Release: 6.0.2 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable') Architecture: i386 (i686) Kernel: Linux 2.6.32-5-686 (SMP w/2 CPU cores) Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Versions of packages linux-image-2.6.32-5-686 depends on: ii coreutils 8.5-1 GNU core utilities ii debconf [debconf-2.0] 1.5.36.1 Debian configuration management sy linux-image-2.6.32-5-686 recommends no packages. Versions of packages linux-image-2.6.32-5-686 suggests: pn fdutils <none> (no description available) pn ksymoops <none> (no description available) pn linux-doc-2.6.32-5-686 | linu <none> (no description available) pn linux-image-2.6.32-5-686-dbg <none> (no description available) -- debconf information: linux-image-2.6.32-5-686/preinst/failed-to-move-modules-2.6.32-5-686: linux-image-2.6.32-5-686/postinst/kimage-is-a-directory: linux-image-2.6.32-5-686/postinst/depmod-error-initrd-2.6.32-5-686: false linux-image-2.6.32-5-686/postinst/ignoring-do-bootloader-2.6.32-5-686: linux-image-2.6.32-5-686/postinst/old-system-map-link-2.6.32-5-686: true linux-image-2.6.32-5-686/postinst/missing-firmware-2.6.32-5-686: * linux-image-2.6.32-5-686/preinst/overwriting-modules-2.6.32-5-686: false linux-image-2.6.32-5-686/prerm/removing-running-kernel-2.6.32-5-686: true linux-image-2.6.32-5-686/postinst/depmod-error-2.6.32-5-686: false linux-image-2.6.32-5-686/postinst/old-dir-initrd-link-2.6.32-5-686: true linux-image-2.6.32-5-686/preinst/abort-overwrite-2.6.32-5-686: * linux-image-2.6.32-5-686/preinst/already-running-this-2.6.32-5-686: -- To UNSUBSCRIBE, email to debian-kernel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20110924193442.3605.25621.reportbug@localhost
