### Dispatch_Compared ###

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USAGE:  Dispatch_Compared [<n_benchmarks> [<n_folds>  [<n_iterations>]]]

All arguments are optional, though the earlier arguments must be specified to use the later ones.

n_benchmarks - argument passed to dispatch_benchmark; more runs reduces fluctuations

n_folds - how many times to run the work_function, to increase computation vs. overhead

n_iterations - maximum # of times to iterate each API

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DESCRIPTION:

This sample code uses dispatch_benchmark to time the performance of

a relatively compute-intensive loop using different APIs:

- simple for loop

- GCD: dispatch_apply

- GCD: serial queue (private)

- GCD: parallel queue (global)

- GCD: multiple queues

- POSIX threads

Please note that this is NOT a "macro" benchmark that compares the real-world performance of different implementations.

Rather, it is a *micro* benchmark that simply shows the overhead of invoking each API that number of times.

Also note that a complete run with the default arguments can take several hours.

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BUILD REQUIREMENTS:

Mac OS X v10.6 or later

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RUNTIME REQUIREMENTS:

Mac OS X v10.6 or later

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PACKAGING LIST:

ReadMe.txt - This document

main.c - Primary source code file

Sample_Results.txt - Sample output plus discussion of results

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CHANGES FROM PREVIOUS VERSIONS:

Version 1.0

- First version.

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Copyright (C) 2009 Apple Inc. All rights reserved.