LAT_SYSCALL(8)

NAME
lat_syscall - time simple entry into the operating system

SYNOPSIS
lat_syscall null|read|write|stat|fstat|open

DESCRIPTION
lat_syscall measures how long it takes to do various simple system call operations.

null
    measures how long it takes to do getppid. This is useful as a lower bound cost on anything that has to interact with the operating system.

write
    measures how long it takes to write one byte to /dev/null.

read
    measures how long it takes to read one byte from /dev/zero.

stat
    measures how long it takes to stat a file.

fstat
    measures how long it takes to fstat a file.

open
    measures how long it takes to open and then close a file. Note that this does not include the time to read the directories or inodes from disk, since everything should be in the buffer cache.

OUTPUT
Output formats are:
Simple syscall: 67 microseconds
Simple write: 67 microseconds
Simple read: 67 microseconds
Simple stat: 67 microseconds
Simple fstat: 67 microseconds
Simple open/close: 67 microseconds

ACKNOWLEDGEMENT
Funding for the development of this tool was provided by Sun Microsystems Computer Corporation.

SEE ALSO
lmbench(8), getppid(2), read(2), write(2), stat(2), fstat(2), open(2), close(2).