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SubjectRe: The reason to call it 3.0 is the desktop (was Re: [OT] 2.6 not 3.0 - (NUMA))
Pardon my ignorance,

How does Readahead relate to journaling filesystems such as ReiserFS, or XFS?

Do they have the same or similar problems that I've been reading about with ext2/3?

Andrew Morton <akpm@digeo.com> scribbled something about Re: The reason to call it 3.0 is the desktop (was Re: [OT] 2.6 not 3.0 - (NUMA)):

> Daniel Phillips wrote:
> >
> > On Sunday 06 October 2002 17:19, Martin J. Bligh wrote:
> > > > Then there's the issue of application startup. There's not enough
> > > > read ahead. This is especially sad, as the order of page faults is
> > > > at least partially predictable.
> > >
> > > Is the problem really, fundamentally a lack of readahead in the
> > > kernel? Or is it that your application is huge bloated pig?
> >
> > Readahead isn't the only problem, but it is a huge problem. The current
> > readahead model is per-inode, which is very little help with lots of small
> > files, especially if they are fragmented or out of order. There are various
> > ways to fix this; they are all difficult[1]. Fortunately, we can call this
> > "tuning work" so it can be done during the stable series.
> >
> > [1] We could teach each filesystem how to read ahead across directories, or
> > we could teach the vfs how to do physical readahead. Choose your poison.
>
> Devices do physical readahead, and it works nicely.
>
> Go into ext2_new_inode, replace the call to find_group_dir with
> find_group_other. Then untar a kernel tree, unmount the fs,
> remount it and see how long it takes to do a
>
> `find . -type f xargs cat > /dev/null'
>
> on that tree. If your disk is like my disk, you will achieve
> full disk bandwidth.
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