Path: utzoo!attcan!uunet!ncrlnk!ncrcae!hubcap!gatech!bloom-beacon!tut.cis.ohio-state.edu!ucbvax!MASIG1.OCEAN.FSU.EDU!mccalpin
From: mccalpin@MASIG1.OCEAN.FSU.EDU ("John D. McCalpin")
Newsgroups: comp.sys.sgi
Subject: Feedback Optimizer
Message-ID: <8903151749.AA06746@masig1.ocean.fsu.edu>
Date: 15 Mar 89 17:49:45 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 31

I have been experimenting with the various optimization parameters 
of the MIPS f77 compiler on a Personal IRIS.  In several places, the
documentation refers to the ability of the system to create and use
a feedback file, which allows the optimizer to make use of profiling
information in a previous run in a new compilation.

The prof(1) manual entry explains how to create the feedback file,
but does not tell how to use it.  Neither do the man pages for f77(1)
or pixie(1). The compiler optimization guide in the C manual does not
refer to this feature either, except that such a feedback file appears
in two figures.

The prof(1) entry tells me to read the entries for umerge(1) and uopt(1)
for further information.  These man pages are not distributed with the
system, either on-line or hard-copy.

I called the hotline and spent some time explaining to the compiler person
there how the system was supposed to work. Now I remember why I quit using
the hotline!  I shouldn't pick on SGI, though, since I got about the same
result by calling MIPS....

So, does anyone know what to do with the feedback file created by
'prof -pixie -feedback feedback_file' to make the compiler/optimizer
use it?
--
----------------------  John D. McCalpin -------------------------
Mesoscale Air-Sea Interaction Group  &  Department of Oceanography
 & Supercomputer Computations Research Institute - Fl State Univ.
mccalpin@masig1.ocean.fsu.edu		mccalpin@nu.cs.fsu.edu
mccalpin@fsu	(BITNET or MFENET)	SCRI::MCCALPIN	(SPAN)
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