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7.24  System statistics

7.24.1  statistics/0, statistics/2

Templates
statistics
statistics(?atom, ?list)
Description

statistics displays statistics about memory usage and run times.

statistics(Key, Value) unifies Value with the current value of the statistics key Key. Value a list of two elements. Times are in milliseconds, sizes of areas in bytes.
Key Description Value
user_time user CPU time [SinceStart, SinceLast]
system_time system CPU time [SinceStart, SinceLast]
cpu_time total CPU time (user + system) [SinceStart, SinceLast]
real_time absolute time [SinceStart, SinceLast]
local_stack local stack sizes (control, environments, choices) [UsedSize, FreeSize]
global_stack global stack sizes (compound terms) [UsedSize, FreeSize]
trail_stack trail stack sizes (variable bindings to undo) [UsedSize, FreeSize]
cstr_stack constraint trail sizes (finite domain constraints) [UsedSize, FreeSize]

Note that the key runtime is recognized as user_time for compatibility purpose.

Errors
Key is neither a variable nor a valid key    domain_error(statistics_key, Key)
Value is neither a variable nor a list of two elements    domain_error(statistics_value, Value)
Value is a list of two elements and an element E is neither a variable nor an integer    type_error(integer, E)

Portability

GNU Prolog predicates.

7.24.2  user_time/1, system_time/1, cpu_time/1, real_time/1

Templates
user_time(?integer)
system_time(?integer)
cpu_time(?integer)
real_time(?integer)
Description

user_time(Time) unifies Time with the user CPU time elapsed since the start of Prolog.

system_time(Time) unifies Time with the system CPU time elapsed since the start of Prolog.

cpu_time(Time) unifies Time with the CPU time (user + system) elapsed since the start of Prolog.

real_time(Time) unifies Time with the absolute time elapsed since the start of Prolog.

Errors
Time is neither a variable nor an integer    type_error(integer, Time)

Portability

GNU Prolog predicates.

Copyright (C) 1999-2007 Daniel Diaz

Verbatim copying and distribution of this entire article is permitted in any medium, provided this notice is preserved.

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