"libtool" performance...

Roland Mainz roland.mainz at nrubsig.org
Mon Apr 14 06:26:11 PDT 2008

Ralf Wildenhues wrote:
> * Roland Mainz wrote on Fri, Apr 11, 2008 at 04:59:15PM CEST:
> > Ok... but "dolt" may been to be adopted to other compilers (like Sun
> > Workshop/Forte/Studio, icc etc.) and then it will be a bit more than the
> > 10 lines (and adopting it for other POSIX-like shells may be nice, too -
> Josh measured against Libtool 1.5.x.  Libtool 2.2.2 has a lot less
> overhead in compile mode than 1.5.x, see the numbers Ross posted, and
> the list archive of libtool-patches for several improvements including
> numbers; and we are currently working on improving things a bit more,
> targeting improvements that help all shells which support XSI
> extensions (and falling back to the slow code for other shells).

What do you mean by "XSI extensions" ?

BTW: One thing which could be improved in both "libtool" and "dolt"
(beyond the stuff listed in
http://www.opensolaris.org/os/project/shell/shellstyle/) would be to get
rid of the "echo" h*ll - almost every version of Unix/Linux and shell
has it's own version of "echo" (Solaris even has multiple one:
/usr/bin/echo, /usr/ucb/echo, /usr/gnu/echo and the { bash, Bourne, csh,
ksh88, ksh93, zsh } builtin version of "echo" - all of them with
slightly different behaviour).
A more portable solution would be to use the "printf" command (which is
usually a shell builtin (at lest in bash+ksh93's case)) which is part of
the POSIX standard (the POSIX people were aware of the "echo" h*ll since
a long time and choose to create a new utilty than trying to fight each
and every OS+shell vendor/author... :-) ) and therefore has guranteed
behaviour for quoting, backslashes etc. (and avoids undesired
sideeffects when a variable contains backslashes, e.g. $ foo="\a
chicken" ; echo "$foo" # will result in some OS/shell-specific string
while $ foo="\a chicken" ; printf "%s\n" "$foo" # will precisely print

> While the multi-thousand line script can't get as fast as dolt -- after
> all, dolt isn't portable to non-bash,

Well, I can provide patches to make it at least compatible to all POSIX
compatible shells (AFAIK that would only require minor adjustments...).

> also there's functionality that
> libtool compile mode offers that dolt doesn't -- we expect compile mode
> to become fast enough that the overhead shouldn't be a big problem for
> practical use, and we expect that to come without the need for users to
> change their configure.ac scripts at all.
> Meanwhile, updating to 2.2.2 would be a good idea, its link mode has
> also become considerably faster than 1.5.x at least for some use cases.
> We would appreciate bug reports for particular remaining performance
> bottlenecks.

Question for both "dolt" and "libtool" developers:
Where should I send bug reports/patches to ?



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