[Info-vax] Current VMS Usage Survey

[John Reagan]

On Thursday, December 5, 2013 8:11:18 AM UTC-5, Michael Kraemer wrote:
> In article <bgb9gjFb5thU2 at mid.individual.net>, bill at server3.cs.scranton.edu
> 
> (Bill Gunshannon) writes:

> > Even the "smart compilers" that  
> > were going to be able to modify code based on profiling information
> > (did anyone ever actually do this?) struck me as a cute but improbable
> > idea.
> 
> Yep, yet another flaw in the Itanic concept.
> But it was OK to give it at least a try.

The HP-UX Itanium compiler provides PBO (Profile Based Optimization).  The NSK Itanium compiler provides PGO (Profile Guided Optimization).  Same concept, different TLA.  Compiler instruments the code, you run it to count various things, a data file written out, you compile again using that data file.

On Alpha, the Tru64 compilers had some PGO-like tools.  GEM has the support to use profiling data.  It was never enabled/ported to OpenVMS.

GCC provides PGO for x86 targets (-fprofile-generate and -fprofile-use) and so does Open64.  I've seen discussions to add PGO to LLVM in the future.