The predicate statistics/2
is built-in. More high level predicates are available from library library(statistics).
See section A.51.
Starting with version 9.1.9, the cputime and inferences
keys include the final value for threads that have been created by the
calling thread and has been joined by the calling
thread. The new keys self_cputime and self_inferences
may be used to get statistics for the calling thread only. Both keys
also exist in the single threaded version, where the “self'' key
always returns the same value as the onle without “self''.
| Native keys (times as float in seconds) | |
| agc | Number of atom garbage collections performed |
| agc_gained | Number of atoms removed |
| agc_time | Time spent in atom garbage collections |
| atoms | Total number of defined atoms |
| atom_space | Bytes used to represent atoms |
| c_stack | System (C-) stack limit. 0 if not known. |
| cgc | Number of clause garbage collections performed |
| cgc_gained | Number of clauses reclaimed |
| cgc_time | Time spent in clause garbage collections |
| clauses | Total number of clauses in the program |
| codes | Total size of (virtual) executable code in words |
| cputime | (User) CPU
time since thread was started in seconds. Includes CPU
time in completed child threads. See also self_cputime
and process_cputime. |
| epoch | Time stamp when thread was started |
| errors | Number of error mesages printed |
| functors | Total number of defined name/arity pairs |
| functor_space | Bytes used to represent functors |
| global | Allocated size of the global stack in bytes |
| globalused | Number of bytes in use on the global stack |
| globallimit | Size to which the global stack is allowed to grow |
| global_shifts | Number of global stack expansions |
| heapused | Bytes of heap in use by Prolog (0 if not maintained) |
| inferences | Total number of passes via the call and redo
ports since Prolog was started. Includes inferences in
child threads. See also self_inferences. |
| modules | Total number of defined modules |
| local | Allocated size of the local stack in bytes |
| local_shifts | Number of local stack expansions |
| locallimit | Size to which the local stack is allowed to grow |
| localused | Number of bytes in use on the local stack |
| table_space_used | Amount of bytes in use by the thread's answer tables |
| trail | Allocated size of the trail stack in bytes |
| trail_shifts | Number of trail stack expansions |
| traillimit | Size to which the trail stack is allowed to grow |
| trailused | Number of bytes in use on the trail stack |
| shift_time | Time spent in stack-shifts |
| self_cputime | (User) CPU time since thread was started in seconds |
| self_inferences | Total number of passes via the call and redo ports since Prolog was started |
| stack | Total memory in use for stacks in all threads |
| predicates | Total number of predicates. This includes predicates that are undefined or not yet resolved. |
| indexes_created | Number of clause index tables creates. |
| indexes_destroyed | Number of clause index tables destroyed. |
| process_epoch | Time stamp when Prolog was started |
| process_cputime | (User) CPU time since Prolog was started in seconds |
| thread_cputime | MT-version: Seconds CPU time used by finished threads. The implementation requires non-portable functionality. Currently works on Linux, MacOSX, Windows and probably some more. |
| threads | MT-version: number of active threads |
| threads_created | MT-version: number of created threads |
| engines | MT-version: number of existing engines |
| engines_created | MT-version: number of created engines |
| threads_peak | MT-version: highest id handed out. This is a fair but possibly not 100% accurate value for the highest number of threads since the process was created. |
| warnings | Number of warning mesages printed |
| Compatibility keys (times in milliseconds) | |
| runtime | [ CPU time, CPU time since last ] (milliseconds, excluding time spent in garbage collection) |
| system_time | [ System CPU time, System CPU time since last ] (milliseconds) |
| real_time | [ Wall time, Wall time since last ] (integer seconds. See get_time/1) |
| walltime | [ Wall time since start, Wall time since last] (milliseconds, SICStus compatibility) |
| memory | [ Total unshared data, free memory ] (Used is
based on ru_idrss from getrusage(). Free is based on RLIMIT_DATA
from getrlimit(). Both are reported as zero if the OS lacks support.
Free is -1 if getrlimit() is supported but returns infinity.) |
| stacks | [ global use, local use ] |
| program | [ heap use, 0 ] |
| global_stack | [ global use, global free ] |
| local_stack | [ local use, local free ] |
| trail | [ trail use, trail free ] |
| garbage_collection | [ number of GC, bytes gained, time
spent, bytes left ] The last column is a SWI-Prolog extension. It
contains the sum of the memory left after each collection, which can be
divided by the count to find the average working set size after GC. Use [Count,
Gained, Time|_] for compatibility. |
| stack_shifts | [ global shifts, local shifts, time spent ] |
| atoms | [ number, memory use, 0 ] |
| atom_garbage_collection | [ number of AGC, bytes gained, time spent ] |
| clause_garbage_collection | [ number of CGC, clauses gained, time spent ] |
| core | Same as memory |