This library provides predicates to obtain information about resource
usage by your program. The predicates of this library are for human use
at the toplevel: information is printed. All predicates obtain
their information using public low-level primitives. These primitives
can be use to obtain selective statistics during execution.
- [det]statistics
- Print information about resource usage using print_message/2.
- See also
- All statistics printed are obtained through statistics/2.
- [det]statistics(-Stats:dict)
- Stats is a dict representing the same information as
statistics/0.
This convience function is primarily intended to pass statistical
information to e.g., a web client. Time critical code that wishes to
collect statistics typically only need a small subset and should use statistics/2
to obtain exactly the data they need.
- [nondet]thread_statistics(?Thread,
-Stats:dict)
- Obtain statistical information about a single thread. Fails silently of
the Thread is no longer alive.
| Stats | is a dict containing status, time and
stack-size information about Thread. |
- [nondet]time(:Goal)
- Execute Goal, reporting statistics to the user. If Goal
succeeds non-deterministically, retrying reports the statistics for
providing the next answer.
Statistics are retrieved using thread_statistics/3
on the calling thread. Note that not all systems support thread-specific
CPU time. Notable, this is lacking on MacOS X.
- See also
- - statistics/2
for obtaining statistics in your program and understanding the reported
values.
- call_time/2, call_time/3
to obtain the timing in a dict.
- bug
- Inference statistics are often a few off.
- call_time(:Goal,
-Time:dict)
- call_time(:Goal,
-Time:dict, -Result)
- Call Goal as call/1,
unifying Time with a dict that provides information on the
resource usage. Currently Time contains the keys below.
Future versions may provide additional keys.
- wall:Seconds
- cpu:Seconds
- inferences:Count
| Result | is one of true or false
depending on whether or not the goal succeeded. |
- profile(:Goal)
- profile(:Goal,
+Options)
- Run Goal under the execution profiler. Defined options are:
- time(Which)
- Profile
cpu or wall time. The default is CPU
time.
- top(N)
- When generating a textual report, show the top N predicates.
- cumulative(Bool)
- If
true (default false), show cumulative
output in a textual report.
- show_profile(+Options)
- Display last collected profiling data. Options are
- top(N)
- When generating a textual report, show the top N predicates.
- cumulative(Bool)
- If
true (default false), show cumulative
output in a textual report.
- [det]profile_data(-Data)
- Gather all relevant data from profiler. This predicate may be called
while profiling is active in which case it is suspended while collecting
the data. Data is a dict providing the following fields:
summary:Dict- Overall statistics providing
- samples:Count: Times the statistical profiler was called
- ticks:Count Virtual ticks during profiling
- accounting:Count Tick spent on accounting
- time:Seconds Total time sampled
- nodes:Count Nodes in the call graph.
- nodes
- List of nodes. Each node provides:
- predicate:PredicateIndicator
- ticks_self:Count
- ticks_siblings:Count
- call:Count
- redo:Count
- exit:Count
- callers:
list_of(Relative)
- callees:
list_of(Relative)
Relative is a term of the shape below that represents a caller
or callee. Future versions are likely to use a dict instead.
node(PredicateIndicator, CycleID, Ticks, TicksSiblings,
Calls, Redos, Exits)
- [nondet]profile_procedure_data(?Pred,
-Data:dict)
- Collect data for Pred. If Pred is unbound data for
each predicate that has profile data available is returned. Data
is described in
profile_data/1
as an element of the
nodes key.
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