Re: [RFC] extents support for EXT3

From: Ed Sweetman
Date: Fri Aug 29 2003 - 10:54:31 EST


Alex Tomas wrote:
Ed Sweetman (ES) writes:


ES> If it's the same as test2 then i've already tried it. I got no
ES> performance gains as far as dbench is concerned. Perhaps my block
ES> size is not optimal on that partition for extents. Either way it
ES> seemed to make the kernel unstable and i've been trying to fix things
ES> since mid-day yesterday. Been getting very strange problems, no error
ES> messages are reported or anything like that.

I still use -test2, because -test4 detects my scsi hdds in another order
than -test2. last time I sent rediff against -test4. what kind of problem
did you see?


in the kernels that would boot (for some reason test4's videodev driver is borked so i used the mm patchset) passed the serio drivers, init was unable to be found, no matter what even though it mounted the root fs and the root fs is not as far as i can tell when booting on older kernels, corrupted. I'm writing now in mozilla from the very system but with extents turned off. I'm somewhat afraid though that even though i didn't mount the partitions with the extents option, that the patch may still be having an adverse effect. Right now things seem pretty stable but last night apt was hanging while generating locales reproducably causing the entire kernel to lose the ability to do anything to the fs. This was all being tested on test3-mm1. I am aware that mm does have some patches to ext3 that aren't in the main kernel i believe. perhaps the xattr stuff is conflicting in some way? I really have no way of testing the linus tree directly because the drivers i use wont compile.


All in all though, when it was enabled, i saw really no difference from when it was not enabled. dbench 16 gave me ~140MB/sec either way. md5summing large files resulted in equal performance as well. I got nothing even close to the kind of performance increases you showed in the first mail.

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