proc.timedetermines how much real and CPU time (in seconds) the currently running R process has already taken.
"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
summarymethod 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 likeThe 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
NA.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.
proc.timereturns five elements for backwards compatibility, but its
system.timefor timing an R expression,
gc.timefor how much of the time was spent in garbage collection.