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- .\" $Id$
- .TH LAT_SYSCALL 8 "$Date$" "(c)1994 Larry McVoy" "LMBENCH"
- .SH NAME
- lat_syscall - time simple entry into the operating system
- .SH SYNOPSIS
- .B lat_syscall
- .I "null|read|write|stat|fstat|open"
- .SH DESCRIPTION
- .B lat_syscall
- measures how long it takes to do various simple system call
- operations.
- .TP
- .B null
- measures how long it takes to do
- .BR getppid .
- This is useful as a lower bound cost on anything that has to interact
- with the operating system.
- .TP
- .B write
- measures how long it takes to write one byte to \f(CB/dev/null\fP.
- .TP
- .B read
- measures how long it takes to read one byte from \f(CB/dev/zero\fP.
- .TP
- .B stat
- measures how long it takes to
- .B stat
- a file.
- .TP
- .B fstat
- measures how long it takes to
- .B fstat
- a file.
- .TP
- open
- measures how long it takes to
- .B open
- and then
- .B 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.
- .SH OUTPUT
- Output formats are:
- .ft CB
- .br
- Simple syscall: 67 microseconds
- .br
- Simple write: 67 microseconds
- .br
- Simple read: 67 microseconds
- .br
- Simple stat: 67 microseconds
- .br
- Simple fstat: 67 microseconds
- .br
- Simple open/close: 67 microseconds
- .ft
- .SH ACKNOWLEDGEMENT
- Funding for the development of
- this tool was provided by Sun Microsystems Computer Corporation.
- .SH "SEE ALSO"
- lmbench(8), getppid(2), read(2), write(2), stat(2), fstat(2), open(2),
- close(2).
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