Re: [gentoo-dev] Gentoo kernel and XFS

[Emiel Kollof <coolvibe@hackerheaven.org>]

On Wednesday 11 September 2002 05:23, Brandon Low wrote:

> Use the latest xfs-sources.  Has xfs and other useful things, but none of
> the performance patches that mess things up...

It's not messing anything up. It's just not doing anything, which is a bit of 
a waste. My idea was to use the latest xfs sources, but if I knew which 
patches were in the gentoo-enhanced kernel, I could chuck them in there as 
well. Robert Love, the creator of the preempt patch says that preemt-kernel 
and XFS do play nice together, as long as XFS keeps it's act clean and neatly 
disposes of it's locks instead of just trashing them when it doesn't need it 
anymore :) 

XFS is very stable, production use stable even. It passed all my file 
corruption tests with flying colors, and it can deal with the size of files I 
usually juggle around, which are big raw unedited full motion video files 
which easily take up multiple gigabytes. 

Oh, and those patches are useful to me, since I need low latency for stuff 
like video editing (which somewhat needs real-time preformance and low 
latency). I can't just drop them, my video editing tools would turn out crap. 
I got some good latency times on an ext3 fs and the already present 
performance patches (latency times around a few milliseconds, which is just 
about doable), but the filesystem sucked. So I switched to xfs. Great 
filesystem, fits my needs perfectly, but now the preempt-kernel isn't 
preempting and I'm seeing the latency times skyrocket because some procs are 
seizing cycles when they shouldn't and things start to skip horridly. Urgh. 

> Or quit using xfs, and use my personal fav. reiserfs and then use
> gentoo-sources-2.4.19-r9

Quit using XFS? Not an option. I'm not too fond of backing all this crap up 
It's a lot, hence the XFS. I'm talking hundreds of GB's here. Some files grow 
generously larger 2 GB as well. Sucks to be me huh? 

Oh, and I don't like reiser. It's great for small files, but I don't have many 
of those, other than the usual. I did some tests with a fairly recent 
reiserfs once, and it showed me that it sucked for the size of databases and 
raw movie files I usually muck with. It's not a bad fs, but the wrong tool 
for my job/hobbies/whatever.

But I'm digressing: So far, the only two things I could discern wrt 
performance patches are the O(1) scheduler and the preemptible kernel. Is 
there any more you folks propped in there, other than those two?

Cheers,
Emiel