Much faster? i18n? tls?

Behdad Esfahbod behdad at cs.toronto.edu
Tue Nov 11 03:18:18 UTC 2003


On Mon, 10 Nov 2003, Ulrich Drepper wrote:
> Behdad Esfahbod wrote:
> >>>Was tweaking with the grep patch, and also tracking another
> >>>thread in another list, which was showing how on Red Hat 9 a
> >>>simple text intensive program (called hspell) is much slower than
> >>>Red Hat 8, and investigations have shown so far that it's all
> >>>caused by /lib/tls.  Switching to /lib/i686 makes things go much
> >>>faster.  Any idea?  And it's not a multi-threaded application.
>
> I doubt that going with the /lib/i686 version makes it faster.  In fact,
> the TLS code should be between 5-10% faster.

I've already seen the thread on LKML with Linus which I assume
solves this problem.

> >>>[behdad at mces behdad]$ time sed -e 's/./x/g' /bin/ls > /dev/null
> >>>
> >>>real    0m4.248s
> >>>user    0m3.800s
> >>>sys     0m0.000s
> >>>[behdad at mces behdad]$ time LANG=C sed -e 's/./x/g' /bin/ls > /dev/null
> >>>
> >>>real    0m0.180s
> >>>user    0m0.050s
> >>>sys     0m0.000s
> >>>[behdad at mces behdad]$
>
> That's expected.  UTF-8 handling is complicated.  And we do have special
> support for single-byte encodings.  You should be happy about that.

Sure, but UTF-8 is not such a hard thing to handle.

> Having this said, we might have some speedups for the regex code at some
> point.  Speedups specifically for UTF-8.  If you want to see this
> sooner, get out your editor and start hacking regex.

I would definitely do.  I'm afraid the problem is not UTF-8
itself, but other legacy multi-byte ones.  I mean, may it be that
special support for UTF-8 may be needed...

behdad





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