4.12  Time and Memory

• Timing

4.12.1  Timing

Timings are available via the built-in predicates cputime/1nd statistics/2 To obtain the CPU time consumption of a (succeeding) goal, use the scheme

cputime(StartTime),
my_goal,
TimeUsed is cputime-StartTime,
printf("Goal took %.2f seconds%n", [TimeUsed]).

The statistics/2 and statistics/0 commands can also be used to obtain memory usage information. The memory areas used by ECLⁱPS^e are:

Shared and private heap

for compiled code, non-logical store ( bags and shelves, findall) dictionary of functors, various tables and buffers.

Global stack

for most ECLⁱPS^e data like lists, structures, suspensions. This is likely to be the largest consumer of memory.

Local stack

for predicate call nesting and local variables.

Control and trail stack

for data needed on backtracking.

Automatic garbage collection is done on the global and trail stack, and on the dictionary. Garbage collection parameters can be set using set_flag/2 and an explicit collection can be requested using garbage_collect/0.