proc.time {base}R Documentation

Running Time of R


proc.time determines how much real and CPU time (in seconds) the currently running R process has already taken.




proc.time returns five elements for backwards compatibility, but as from R 2.5.0 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 rounded to the nearest 1ms. On modern systems they will be that accurate, but on older systems they might be accurate to 1/100 or 1/60 sec.
It is most useful for “timing” the evaluation of R expressions, which can be done conveniently with system.time.


It is possible to compile R without support for proc.time, when the function will throw an error.


Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

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(runif(500))
proc.time() - ptm
## End(Not run)

[Package base version 2.5.0 Index]