profiler
This tool contains simple wrappers for selected Prolog profiler tools.
Loading
This tool can be loaded using the query:
?- logtalk_load(profiler(loader)).
For sample queries, please see the SCRIPT.txt
file in the tool
directory.
Testing
To test this tool, load the tester.lgt
file:
| ?- logtalk_load(profiler(tester)).
Supported backend Prolog compilers
Currently, this tool supports the profilers provided with SICStus Prolog 4, SWI-Prolog, and YAP. The tool includes two files:
yap_profiler.lgt
simple wrapper for the YAP count profilersicstus_profiler.lgt
simple wrapper for the SICStus Prolog 4 profiler
Logtalk also supports the YAP tick profiler (using the latest YAP
development version) and the SWI-Prolog XPCE profiler. When using the
XPCE profiler, you can avoid profiling the Logtalk compiler (which is
invoked e.g. when you use the (::)/2
message-sending operator at the
top-level interpreter) by compiling your code with the optimize
flag
turned on:
?- set_logtalk_flag(optimize, on).
true.
?- use_module(library(statistics)).
true.
?- profile(... :: ...).
...
Given that prolog_statistics:profile/1
is a meta-predicate, Logtalk
will compile its argument before calling it thanks to the
goal_expansion/2
hook predicate definitions in the adapter file.
Without this hook definition, you would need to use instead (to avoid
profiling the compiler itself):
?- logtalk << (prolog_statistics:profile(... :: ...)).
...
In either case, Don’t forget, however, to load the prolog_statistics
module before using or compiling calls to the profile/1
to allow
the Logtalk compiler to access its meta-predicate template.
The profiler support attempts to conceal internal Logtalk
compiler/runtime predicates and the generated entity predicates that
implement predicate inheritance. Calls to internal compiler and runtime
predicates have functors starting with $lgt_
. Calls to predicates
with functors such as _def
, _dcl
, or _super
, used to
implement inheritance, may still be listed in a few cases. Note that the
time and the number of calls/redos of concealed predicates is added to
the caller predicates.
Compiling source code for profiling
In order to get user-level object and predicate names instead of
compiler generated internal names when using the SWI-Prolog and YAP
profilers, you must set code_prefix
flag to a character other than
the default $
before compiling your source code. For example:
?- set_logtalk_flag(code_prefix, '.').
See also the settings-sample.lgt
file for automating the necessary
setup at Logtalk startup.