NAME

time, ptime − time a command

SYNOPSIS

time [ −a ] [ −r ] [ −v ] command

ptime [ −a ] [ −r ] [ −v ] command

DESCRIPTION

After a given command has been executed, time prints the elapsed time during the command, the time spent in the system, and the time spent in execution of the command.  Time is reported in seconds. 

OPTIONS

When the −a option is specified, or when invoked as ptime, time shows the execution time for each process. 

When the −r option is specified, time also includes resource usage information. 

The resource usage fields are:

pid numerical user-id of process owner

ppid numerical user-id of parent of process

MaxRSS maximum real memory (resident set) size (in pages)

MajorPF major page faults

MinorPF minor page faults

Swaps count of process swaps

blkI count of block input operations

blkO count of block output operations

Nsig count of signals received

Vcsw voluntary context switches

Icsw involuntary context switches

When the −v option is specified, time traces process events such as fork, exec, and exit as they occur. 

The times are printed on the diagnostic output stream. 

Time is a built-in command to csh(1), with a different syntax and a different output format.  This command is available as /bin/time to csh users. 

BUGS

Due to the multiprocessing nature of DYNIX, it is possible for the CPU time (user + system time) for the command to greatly exceed real time, thus giving percentages greater than 100% for CPU utilization. 

The −a option returns a smaller number for the system time because it does not include the time used to exit the process. 

Using ptime to measure parallel fork/exit times results in serializing all fork and exit operations in the program being timed.  These results are misleading as parallel fork/exit does perform faster than a sequential implementation. 

4BSD