🚀 go-pugleaf

Valentin Nechayev wrote:

> `shared' affects execution time in the only way: it requires additional
> time for dynamic linker to load library, parse its export and import
> list, resolve unresolved links in this list. This time is spent once
> on any program startup. It is usually too small, but can be very huge.
> E.g., mozilla-1.0 loads on my at-work Linux box (Intel CC820, Celeron 900)
> for 8 seconds, and 7.5 seconds of them are dedicated to load dynamic
> libraries and resolve cross links. (There are special options in new
> binutils which compresses cross-link lists for faster parsing,
> `-fcombreloc' for ld; this wasn't applied yet to this mozilla package.)

I can live with long startup time.  The execution time is much longer,
so that's the important thing.

> FM> I never used the linker explicitly before, relying on gcc to
> FM> pull it all together.  Now, I'm looking at "man ld", which
> FM> is the sunOS5.8 man page, and I'm not sure if it is the same
> FM> one that gcc uses.  Is there any reason to think otherwise?
>
> It isn't subject to make huge thinking, it is trivially testable.
> Run gcc of any test example (even "Hello world") with -v.

Well, thanks for the advice.  It wasn't obvious to me how to
obtain the information, but your suggestion to use -v revealed
that it was the solaris linker.

> FM> In the end, I'm still left with the question of how to
> FM> invoke a shared library function outside of matlab.
> FM> This is for the sake of speed comparison with the
> FM> nonshared version, as the nonshared version is run
> FM> from outside of matlab.
>
> Trivial program will be similar to
> main() {
>   int (*func)(int);
>   lib = dlopen( "yourlib.so", RTLD_LAZY );
>   if( !lib ) { fprintf( stderr, "dlopen(): %s\n", dlerror() ); return 1; }
>   func = dlsym( lib, "function" );
>   if( !func ) { fprintf( stderr, "dlsym(): %s\n", dlerror() ); return 1; }
>   printf( "%d\n", func(1) );
> }

OK, that's quite a bit of new material (can't say I recognize
any of it).  I'll have to do some digging and reading before
I make use of it.  Thanks.

Fred