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    SubjectRe: Poor floppy performance in kernel 2.4.10
    On Oct 18, 2001  12:11 +0200, Kamil Iskra wrote:
    > So, to reiterate, the conditions known to be necessary to reproduce it
    > are: kernel >=2.4.10 (perhaps only the Linus series), small files or
    > directory operations, mtools. The behaviour is as if no caching was done,
    > there is a slowdown by a factor of two. I have this problem both on my
    > laptop and on the desktop machine at work. They are running different
    > kernel versions (2.4.12 and 2.4.10), differently configured and compiled
    > by two different people. Kernel 2.4.9 and earlier worked fine.

    I think this is a result of the "blockdev in pagecache" change added in
    2.4.10. One of the byproducts of this change is that if a block device
    is closed (no other openers) then all of the pages from this device are
    dropped from the cache. In the case of a floppy drive, this is very
    important, as you don't want to be cacheing data from one floppy after
    you have inserted a new floppy.

    In contrast, if you mounted the floppy instead of using mtools, it would
    probably have good performance for small files as well.

    Cheers, Andreas
    --
    Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto,
    \ would they cancel out, leaving him still hungry?"
    http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert

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