[GRASS-dev] ramdisk as mapset?

[Glynn Clements]

Hamish wrote:

> > If you are concerned about efficiency, build GRASS with profiling
> > support, and look at where the actual inefficiency lies. It would help
> > to do the same for 4.x, as that is reported to be an order of
> > magnitude faster than 5.x/6.x for some tasks.
> 
> Could you suggest a quick usage guide as to how to do that? 
> What's the best tool?
>  * 'gcc -pg' + gprof?
>  * valgrind's calltree -> kcachegrind?
>     (calltree doesn't need a special recompile)

I trust gcc/gprof more than valgrind, particularly where most of the
CPU time is in "leaf" functions (i.e. the module making many calls to
trivial functions in shared libraries, e.g. G_is_?_null_value()).

However, it's harder to use, and can't trace into shared libraries (or
any libraries built without profiling support), so you have to build
GRASS with --disable-shared.

-- 
Glynn Clements <glynn at gclements.plus.com>