Re: profile-driven optimization and the linker?

[Dan Kegel <dank at kegel dot com>]

Will Cohen wrote:
> > > http://gcc.gnu.org/news/profiledriven.html doesn't mention
> > > having ld reorder sections to improve locality of reference
> > > of frequently called functions.    Has that technique
> > > been tried with gcc and binutils?
> >
> > Yes.  I had some success with it a while back.  ...
> > We had some hacks to gprof which would take profile data
> > and build a linker map.  That's the code that really needs
> > to be improved.  I never understood the gprof code well
> > enough to do it right.  ...
>
> There are a couple of students doing a ECE senior design project at 
> North Carolina Statue University using valgrind/callgrind to collect 
> call-graph information. The information is feed into a program to 
> generate a link script. It should do something similar to ROPE assuming 
> that the code is compiled with -ffunction-section. There should be some 
> information available on it in the near future, the NCSU semester is 
> wrapping up.

Excellent.  I'm trying to put together a similar project for
a course at UCLA, and it'd be nice to be able to build on
what the NCSU project did.
- Dan

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