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Re: reading an empty directory after reboot is very slow

On 2015-04-13 15:50:40 -0500, David Wright wrote:
> That's staggering. My /var/lib/dpkg/info has ~8900 files and occupies
> 462848 bytes. So that would be over ½million files in your case.
> Does eftests stand for "excessive files tests"!

It means "elementary function tests", but what this doesn't say is
that these tests are exhaustive: 1 file = a small interval on which
the double-precision function (e.g. exp, log) can be approximated
by a small-degree polynomial, and the whole double-precision domain
must be covered.

Now, more interestingly, the fault is due to... proprietary software.
I wrote these tests about 15 years ago and I needed rigorous interval
arithmetic in multiple precision, and at that time, the Maple intpak
package was the only thing I found (though a few years later, despite
what its documentation said, it was shown that it was not rigorous at
all, and I might have chosen a better solution with free software).
So, I had to use Maple, and still use it (now with intpakX, which is
better but still based on assumptions that could be wrong) because I
haven't rewritten my tests completely. Maple is only used for ISO C
code generation. In normal use, code is generated, then run, and after
a few minutes (to get the result), the corresponding program can be
removed, so that few files are present in such a directory at the same
time. But some colleague in another lab needed these test files and he
didn't have Maple. So, I had to generate all of them (yes, something
like half a million) and give him a huge compressed tar file (not sent
by e-mail, of course!).

Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)

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