Re: Basic-Block Profiling Isn't Always Accurate

glew@pdx007.intel.com (Andy Glew)
Thu, 11 Mar 1993 07:14:09 GMT

          From comp.compilers

Related articles
Basic-Block Profiling Isn't Always Accurate larus@primost.cs.wisc.edu (1993-03-08)
Re: Basic-Block Profiling Isn't Always Accurate anik@crhc.uiuc.edu (1993-03-09)
Re: Basic-Block Profiling Isn't Always Accurate glew@pdx007.intel.com (1993-03-11)
Re: Basic-Block Profiling Isn't Always Accurate pohua@gomez.intel.com (1993-03-12)
Re: Basic-Block Profiling Isn't Always Accurate pardo@cs.washington.edu (1993-03-14)
| List of all articles for this month |

Newsgroups: comp.arch,comp.compilers
From: glew@pdx007.intel.com (Andy Glew)
Keywords: performance, architecture
Organization: Intel Corp., Hillsboro, Oregon
References: 93-03-024 93-03-027
Date: Thu, 11 Mar 1993 07:14:09 GMT

        For example "Trace Selection for Compiling Large C Application
        Programs to Microcode" by P. P. Chang and W. W. Hwu in MICRO-21 1988,
        discusses the benefit of using edge profile information in trace
        selection.


In private conversation, Pohua (P.P. Chang) has indicated that he rarely
finds edge profile information useful in trace selection - i.e. the
additional information is rarely used to generate better code.


I must admit that I find this surprising. I (and many others, I'm sure)
pushed for edge profiling, because I have found edge probability info
useful in doing hand assembly code -- and I usually expect that something
I can do by hand should be automatable. It may be that none of the
optimizations Pohua uses really benefit from edge profiling, but that
there may be others that do.


Pohua - if you are out there, care to comment? Have I blatantly
misrepresented you? Do you now find edge profiling really useful feedback
for a compiler?
--
Andy Glew, glew@ichips.intel.com
Intel Corp., M/S JF1-19, 5200 NE Elam Young Pkwy,
Hillsboro, Oregon 97124-6497
--


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