1995-04-19 11:15:50 +04:00
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.\" $NetBSD: intro.me,v 1.2 1995/04/19 07:16:42 cgd Exp $
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.\"
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1994-05-17 07:13:30 +04:00
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.\" Copyright (c) 1982, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)intro.me 8.1 (Berkeley) 6/8/93
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.\"
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.sh 1 "Programs to be Profiled"
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.pp
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Software research environments
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normally include many large programs
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both for production use and for experimental investigation.
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These programs are typically modular,
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in accordance with generally accepted principles
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of good program design.
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Often they consist of numerous small routines
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that implement various abstractions.
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Sometimes such large programs are written
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by one programmer
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who has understood the requirements for
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these abstractions, and has programmed them
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appropriately.
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More frequently the program has
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had multiple authors and has
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evolved over time, changing the demands placed
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on the implementation of the abstractions without
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changing the implementation itself.
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Finally, the program may be assembled from a library
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of abstraction implementations
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unexamined by the programmer.
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.pp
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Once a large program is executable,
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it is often desirable to increase its speed,
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especially if small portions of the program
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are found to dominate its execution time.
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The purpose of the \fBgprof\fP profiling tool is to
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help the user evaluate alternative implementations
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of abstractions.
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We developed this tool in response to our efforts
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to improve a code generator we were writing [Graham82].
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.pp
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The \fBgprof\fP design takes advantage of the fact that the programs
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to be measured are large, structured and hierarchical.
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We provide a profile in which the execution time
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for a set of routines that implement an
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abstraction is collected and charged
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to that abstraction.
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The profile can be used to compare and assess the costs of
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various implementations.
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.pp
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The profiler can be linked into a program without
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special planning by the programmer.
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The overhead for using \fBgprof\fP is low;
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both in terms of added execution time and in the
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volume of profiling information recorded.
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