1998-01-09 09:54:27 +03:00
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.\" $NetBSD: 1.t,v 1.2 1998/01/09 06:54:28 perry Exp $
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.\"
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1994-06-19 04:07:16 +04:00
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.\" Copyright (c) 1985 The Regents of the University of California.
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.\" 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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.\" @(#)1.t 5.1 (Berkeley) 4/17/91
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.\"
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.ds RH Introduction
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.af PN 1
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.bp 1
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.NH
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Introduction
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.PP
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The Berkeley Software Distributions of
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.UX
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for the VAX have added many new capabilities that were
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previously unavailable under
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.UX .
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The development effort for 4.2BSD concentrated on providing new
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facilities, and in getting them to work correctly.
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Many new data structures were added to the system to support
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these new capabilities.
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In addition,
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many of the existing data structures and algorithms
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were put to new uses or their old functions placed under increased demand.
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The effect of these changes was that
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mechanisms that were well tuned under 4.1BSD
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no longer provided adequate performance for 4.2BSD.
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The increased user feedback that came with the release of
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4.2BSD and a growing body of experience with the system
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highlighted the performance shortcomings of 4.2BSD.
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.PP
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This paper details the work that we have done since
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the release of 4.2BSD to measure the performance of the system,
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detect the bottlenecks,
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and find solutions to remedy them.
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Most of our tuning has been in the context of the real
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timesharing systems in our environment.
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Rather than using simulated workloads,
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we have sought to analyze our tuning efforts under
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realistic conditions.
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Much of the work has been done in the machine independent parts
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of the system, hence these improvements could be applied to
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other variants of UNIX with equal success.
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All of the changes made have been included in 4.3BSD.
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.PP
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Section 2 of the paper describes the tools and techniques
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available to us for measuring system performance.
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In Section 3 we present the results of using these tools, while Section 4
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has the performance improvements
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that have been made to the system based on our measurements.
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Section 5 highlights the functional enhancements that have
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been made to Berkeley UNIX 4.2BSD.
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Section 6 discusses some of the security problems that
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have been addressed.
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