Most recent kernel where this bug did not occur: 2.6.8.1 (not sure: 2.6.9..2.6.11) Distribution: Slackware 10.2, but i configure and build the kernel with my options Hardware Environment: Notebook Compaq nx8220 (model ) Software Environment: Slackware 10.2, with my kernel, without third-party patches Problem Description: Very slow (ca. 50 kbytes/s writing speed when copying files to my USB Flash) under 2.6.12.6 (and under 2.6.14-rc2-git3). The read speed is about 8 Mbytes/s. Under 2.6.8.1 is the writing speed ca. 3 Mbytes/s. The kernels > 2.6.12.6 run unstable on my laptop (see http://bugzilla.kernel.org/show_bug.cgi?id=5221 ) => i attach here the 2.6.12.6-related logs and config. I use ehci and uhci modules. With uhci (without ehci) the writing speed is about 25 kbytes/s. The related line in my fstab: /dev/sda1 /mnt/flash vfat rw,noauto,sync,nosuid,user,noatime ,umask=0,uid=99,gid=99 0 0 Steps to reproduce: 1) Insert usb flash drive under kernel >= 2.6.12. 2) Mount it. 3) Try to copy a large file onto it.
Created attachment 6136 [details] My kernel .config for 2.6.12.6 The .configs for 2.6.8.1 and 2.6.14-rc2-git3 are based on this config.
Created attachment 6137 [details] /var/log/debug file, 2.6.12.6 How is it created: 1) Delete an old file 2) Restart system 3) Insert USB Flash 4) Mount it 5) Copy a 45 kb large file on it in mc 6) Unmount it 7) Remove it
Created attachment 6138 [details] dmesg output, 2.6.12.6
Just compiled the kernel 2.6.11.12. The USB writing speed is OK (about 3 MBytes/s).
Just detected: the writing speed is OK under 2.6.12.6 if no "sync" option in fstab used for USB flash.
This is a know problem. The problem is that until now, FAT had NEVER cared about "sync", ie: it didn't work as "sync" even if you passed that option However, this has been fixed, so when you use sync it really means "sync", so it gets much slower. You can remove the "sync" option to get more speed
OK, thank you. I will not use "sync" for FAT-volumes more.
*** This bug has been marked as a duplicate of 5258 ***