Re: [PLUG] kernel backports for 2.4

[Fred K Ollinger <follinge@sas.upenn.edu>]

> This morning I found a cool little collection of 2.5 backports to 2.4.
> So I figured I'd give them a whirl and try out the low
> latency/scheduler/packet writing stuff. So far X11 feels a bit more
> responsive. I'm also thinking of doing a format/reinstall of debian
> w/xfs support.
>
>
> Anybody else playing with this stuff?
> http://members.optusnet.com.au/ckolivas/kernel/
> http://people.debian.org/~blade/XFS-Install/

The debian xfs net installer worked great for me. I recommend it to any
debianite who wants xfs and slim install.

The later link, I don't recommend. I patched a 2.4.20 kernel w/ the
following:

1. xfs
2. ptrace
3. ckolivas patches

The first two work ok together.

The later added to the mix was a nightmare. I ran this kernel two places,
incidentally, both w/ ext3 filesystems (much easier upgrade from ext2).

When high disk io kicked in, the whole system froze, kernel and all. I
couldn't ssh in. I thought it was mozilla, b/c that gives me high io at
times, but no, whenever I had any process make the disk drive grind, I had
this kind of freeze.

This really ruined my day. :)

I downgraded immediately.

If you want to alpha test, maybe find out why this happens, I applaud your
efforts. If you want your desktop to magically get faster, but retain
stability, you might be wasting your time. Better to run a stable kernel
instead. It takes longer to reboot.

> Mainly I'm interrested in better performance when gaming and packet
> writing cd-rw's. I haven't followed lkml in quite some time, so I have a
> bit of research to do to catch up. Anybody want to compare notes (off
> list maybe)?

I'll talk more off list as I like to compile kernels regularly. It's fun
and educational. I like to see where we are headed in linux kernel land.

I have not done much with 2.5 in about a dozen releases as I was busy
doing other things w/ my test box.

I have read that 2.5 is ok for most things. However,

1. still can be slower than 2.4, at times
2. floppy io will give you disk corruption. This could show up in other
places as well as it's not well tested. There were tons of fs patches for
nearly every fs.
3. I didn't see any new hardware, nor any other advantages to using the
new kernel.

Quite frankly, at this stage in the game, I find 2.5 to be a bit
disappointing. There seem to be no new features that make it worth a
change from a stable 2.4.

I thought that the jump from 2.2 to 2.4 was quite a big improvement in
driver support and fs support alone. Stability took a while in 2.4. I
think that 2.6.0 might be more stable than 2.4.0 in that the developers
seem to be stabilizing more this time. It seems like people think that the
change of number from odd to even magically makes the kernel stable. The
2.6 will be 2.5 with a different name so we need to make sure that 2.5
looks good.

I don't foresee any nightmares with 2.6 type vm mess that we had with 2.4,
but one can never tell. I was a bit angry with that as well as with the fs
corruption in 2.4.15! Also, one of those 2.4.14 (IIRC) had a broken
loop.o. These things make you not trust the latest stable kernel. :(

Good luck,

sincerly,

Fred
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