proc.time {base} | R Documentation |
proc.time
determines how much real and CPU time (in seconds)
the currently running R process has already taken.
proc.time()
proc.time
returns five elements for backwards compatibility,
but its print
method prints a named vector of
length 3. The first two entries are the total user and system CPU
times of the current R process and any child processes on which it
has waited, and the third entry is the ‘real’ elapsed time
since the process was started.
An object of class "proc_time"
which is a numeric vector of
length 5, containing the user, system, and total elapsed times for the
currently running R process, and the cumulative sum of user and
system times of any child processes spawned by it on which it has
waited. (The print
method combines the child times with those
of the main process.)
The resolution of the times will be system-specific
and times are typically available to 10ms on NT-based versions of Windows.
It is useful for timing the evaluation of R expressions,
which can be done more conveniently with system.time
.
CPU times will be returned as NA
on Windows 9x/ME systems, but
are genuine times on NT4/2000/XP/2003/Vista systems. Times of child
processes are not available and will always be given as NA
.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
system.time
for timing a valid R expression,
gc.time
for how much of the time was spent in garbage
collection.
## Not run: ## a way to time an R expression: system.time is preferred ptm <- proc.time() for (i in 1:50) mad(stats::runif(500)) proc.time() - ptm ## End(Not run)