Re: [PATCH] [cygwin|mingw]: Add cross-compile support to cwrapper (take 6)

[Charles Wilson]

On 8/26/2010 5:20 PM, Charles Wilson wrote:
> On 8/26/2010 4:18 PM, Ralf Wildenhues wrote:
>> Then, please just move the new functions where Peter needs them,
>> if they really need moving, that is.
> 
> I deliberately placed them after func_compile and before func_link, for
> speed-of-parsing reasons. Obviously libtool is used to compile object
> code much more often than it is used to link (since every linked result
> requires one or more, sometimes many more, objects) -- so moving these
> functions ahead of func_compile will impact speed.  How much? Don't
> know; I'll try to generate some numbers.
> 
> OTOH, it is absolutely *required* to move them where Peter wants them,
> since he /must/ use translate some paths if func_compile is to work,
> with MSVC.  So...we have to pay the price regardless.

I tested using 'ncurses' -- which conveniently is built using the system
installed libtool script, rather than including ltmain.sh etc in its own
configury.  The times below are for a complete 'make' (after configure
has already run) -- so it includes a lot more than just "how fast does
libtool --mode=compile go".  But, the ONLY difference between the two is
the relative position of the conversion functions within the libtool
script, so any time differences should be attributable solely to that
change.

Original:
real    25m3.886s
user    6m24.620s
sys     11m13.787s

With the functions moved ahead of func_mode_compile:
real    24m34.235s
user    6m30.590s
sys     11m23.878s


Statistics:
69 executables linked
6  libraries (dlls) linked
654 objects (325 pic, 329 non-pic)

So, when compiling about 325 source code files, the new function order
cost 5 seconds of user time and 10 seconds of system time, total. That's
1/20th of a second slower per file, under:
  cygwin-1.7.6-1
  bash-3.2.51-24
On a 1.67GHz Core 2 Duo machine running Vista.

--
Chuck