Re: Unresponiveness of 2.4.16 revisited

Nathan G. Grennan (ngrennan@okcforum.org)
29 Nov 2001 03:07:00 -0600


On Thu, 2001-11-29 at 02:14, Andrew Morton wrote:

>
> If you can generate hard numbers (just time the RP command, for a start)
> and they show regression, then go ahead and post!
>
> Let's put the atime thing down as a known ext3 problem for a
> while. (does it happen with ext2? You sure?).
>
> Running noatime won't hurt a thing. It just prevents the kernel
> from recording when a file was last accessed, within the file's
> inode. It's a feature whichis used by backup/archiving programs,
> and probably by mailbox monitoring programs (xbiff, etc). People
> turn it off all the time...

ok, I doubled checked things. It seems mounting an ext3 filesystem as
ext2 is somewhat a myth. If the kernel supports ext3 it still mounts it
as ext3 even if /etc/fstab says ext2. When I tried 2.4.16 with ext3
support, but with the journal exactly removed to make it a ext2
filesystem the --rebuild worked just like it does in 2.4.9-13. So it
does seem to be a problem with just ext3, and I guess they changed the
journaling of atimes between the version in 2.4.9-13 and 2.4.16. It all
now makes sense. Thank you for your help.

As for my comment before and Rik's VM vs AA's VM on cache agressiveness,
it looks like I was off. It just seems to vary on some dynamic. I
thought I checked them at the same points after boot, but between
different boots seemed to get different results, who knows.

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