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Some features of sequential ECLiPSe are not fully
supported or make no sense in the parallel version. These include:
- The Debugger: The prolog debugger cannot be used to trace parallel
sessions i.e. programs in which more than one worker is active.
- File queries: When a compiled file contains queries (i.e. lines of
the form
:- <goal>.
or ?- <goal>.
, then these goals will not
be executed in parallel. To start a parallel computation, either start
it from the toplevel, or use the -e command line option.
- Dynamic predicates can currently not be declared parallel.
- Dynamic loading: This feature is not currently available in
the parallel version, but should be available in subsequent releases.
- Unix process related primitives: Currently most primitives such as
socket, accept, listen, exec, wait which depend on private data
structures created by the operating system are not fully
supported. For example, it is currently up to the user to guarantee
that some operations on a socket (such as accept/3) are only performed
on the worker on which the socket in question was created. In future
releases most of these restrictions will be removed, however, it is
likely that some complex builtins (e.g. select/3) will not be completely
supported.
- Timing statistics: The values returned by the statistics(times,_)
builtin do not make sense in a parallel session, since they only refer
to timers local to the worker on which the call is executed. As noted
earlier, elapsed time for a parallel session should be measured using
the statistics(session_time,Time) builtin. It is envisaged that the the
wm_get/2 builtin will be expanded in the future in order to allow
the user to query total cpu usage of all active workers.
Next: Troubleshooting
Up: Parallel Execution
Previous: Parallel Cuts
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1999-08-06