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=================================================================
Logtalk - Object oriented extension to Prolog
Release 2.27.1
Copyright (c) 1998-2006 Paulo Moura. All Rights Reserved.
=================================================================
To load this example and for sample queries, please see the SCRIPT file.
This folder provides simple benchmark tests for comparing Logtalk message
sending performance with direct predicates calls in plain Prolog.
These benchmarks may also be used for comparing Logtalk message sending
performance across Prolog compilers.
This example is made of five source files:
benchmark.lgt
contains the benchmark predicates
plain.lgt
contains a definition for a list length predicate and a predicate
for testing performance of the built-in predicates assertz/1 and
retract/1
module.pl (not loaded by default; see below)
contains the same definition of a list length predicate
encapsulated in a module
object.lgt
contains the same definition of a list length predicate
encapsulated in an object
database.lgt
contains predicates for testing the performance of the built-in
database methods assertz/1 and retract/1
You may have noticed above that the benchmark predicates and the predicates
for plain Prolog testing are both encapsulated in Logtalk source files. The
Logtalk compiler just copies the plain Prolog code to the generated Prolog
files. The reason for using the .lgt extension for these files is just to
make it possible to load all the example code using a single call to the
logtalk_load/1 predicate.
By default, the benchmark tests on the SCRIPT file use a list of 30 elements
as an argument to the list length predicates. Increasing the list length
leads to decreasing performance differences between plain Prolog and Logtalk
as the list length computation time far outweighs the overhead of the message
sending mechanism. Likewise, decreasing the list length leads to increasing
performance differences between plain Prolog and Logtalk (up to the point you
will be measuring the Logtalk message sending mechanism overhead compared to
plain Prolog predicate calls). In real-life applications, only testing can
give you a balanced view on the trade-offs between plain Prolog performance
and Logtalk programming features.
By default, the loader.lgt file used to load the example code does not load
the module.pl file. Edit this file if your Prolog compiler supports a module
system and you want to run some comparative performance tests between plain
Prolog, Prolog modules, and Logtalk objects. Note that you may need to edit
the code on the module.pl file to make any necessary compatibility changes
for your Prolog compiler module system. For most Prolog module systems, the
performance of module calls is close or even identical to the performance of
plain Prolog calls, specially when using imported predicates as opposed to
using explicit module qualification.
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