[Info-vax] Current VMS Usage Survey

[Bill Gunshannon]

In article <36bcad1f-a91d-48fa-8eaa-bcec922da3ae at googlegroups.com>,
	John Reagan <xyzzy1959 at gmail.com> writes:
> 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.

That might be fine if you are running only code you develop in house
and you can continuously re-compile and re-insall applications.  But
is Banner going to do that for every University running their product?
How about Cerner?  I realize they are gone from VMS but the question is
as an application developer would they do that?  And provide new compiles
every couple of weeks so you could keep up?

> 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.

Why?  Because no one saw any real value in it in the real world?


> 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.

How many commercial application developers collect these profiles from
their customers and provide customized binaries afterwards?

Profiling is nothing new.  But trying to build it into the processor
which is going to be many levels separated from the developers was
just plain silly.  Usable in a few very limited environments but of
no use to the general commercial IT world.

bill

-- 
Bill Gunshannon          |  de-moc-ra-cy (di mok' ra see) n.  Three wolves
billg999 at cs.scranton.edu |  and a sheep voting on what's for dinner.
University of Scranton   |
Scranton, Pennsylvania   |         #include <std.disclaimer.h>