Poor floppy performance in kernel 2.4.10

Kamil Iskra (kamil@science.uva.nl)
Wed, 17 Oct 2001 09:36:04 +0200 (CEST)


Hi,

Since kernel 2.4.10, I observe a rather poor performance of the good old
floppy drive. It used to work find in kernel 2.4.9. Kernel 2.4.10 broke
it, and 2.4.12 did not fix it.  I access my floppy using mtools-3.9.7-4 as
found in RH 7.1.

Not knowing anything about the kernel internals, I would say that the
floppy driver does not do any caching anymore. With kernel 2.4.9, "mdir"
of a standard 1.44 MB, completely empty floppy disk takes about 1 second
for the first invocation, and next to nothing for the subsequent ones.
>From 2.4.10 on, it takes over 2 seconds every time. Writing a 30 KB file
with 2.4.9 takes below 3 seconds, with >=2.4.10 it's over 6 seconds.

Maybe I should just keep quiet and be happy that it works at all, after
all floppies are rarely used nowadays, but letting such a performance
degradation go unreported is just beyond me :-).

Regards,

-- 
Kamil Iskra                 http://www.science.uva.nl/~kamil/
Section Computational Science, Faculty of Science, Universiteit van Amsterdam
kamil@science.uva.nl  tel. +31 20 525 75 35  fax. +31 20 525 74 90
Kruislaan 403  room F.202  1098 SJ Amsterdam  The Netherlands

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