Availability:built-in
| 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 |
| epoch | Time stamp when thread was started |
| 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 |
| 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 |
| 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. |
Table 6 : Keys for statistics/2.
Space is expressed in bytes. Time is expressed in seconds, represented
as a floating point number.
| 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 |
Table 7 : Compatibility keys for statistics/2.
Time is expressed in milliseconds.