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,
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
summary method to
combine the child times with those of the main process.)
The definition of ‘user’ and ‘system’ times is from your OS. Typically it is something like
The ‘user time’ is the CPU time charged for the execution of user instructions of the calling process. The ‘system time’ is the CPU time charged for execution by the system on behalf of the calling process.
Times of child processes are not available on Windows and will always
be given as
The resolution of the times will be system-specific and on Unix-alikes times are rounded down to milliseconds. On modern systems they will be that accurate, but on older systems they might be accurate to 1/100 or 1/60 sec. They are typically available to 10ms on Windows.
This is a primitive function.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
system.time for timing an R expression,
gc.time for how much of the time was spent in garbage
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