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From: karsh@trifolium.esd.sgi.com (Bruce Karsh)
Newsgroups: comp.arch
Subject: Re: Compiler Costs
Message-ID: <64045@sgi.sgi.com>
Date: 13 Jul 90 06:15:36 GMT
References: <40052@mips.mips.COM> <628@dg.dg.com>
Sender: karsh@trifolium.esd.sgi.com
Reply-To: karsh@trifolium.sgi.com (Bruce Karsh)
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 21

In article <628@dg.dg.com> publius@dg-pag.webo.dg.com (Publius) writes:

>Many "large" programs spend most of the CPU time in one or a few relatively
>"tiny" routines.

This is an often stated.  Is there any evidence for this?  What does the
distribution of time look like for, for instance, a compiler?  I'd expect
that there would be lots of time-sinks.  The lexical analyzer, the symbol table
hash routine, the symbol table lookup routine, common subexpression finder,
... etc, could all be candidate time-sinks.

How about a text editor?  I could think of a few dozen potential time-sinks
in a text editor.

When I've profiled programs, I've often found that the time is spent mostly
in a few routines, but this isn't always the case.  How often is it true that
nearly all of the time is spent in only a few routines?  How often are these
routines tiny?

			Bruce Karsh
			karsh@sgi.com