dtruss(1m)

NAME
dtruss - process syscall details. Uses DTrace.

SYNOPSIS
dtruss [-acdeflhoLs] [-t syscall] { -p PID | -n name | command }

DESCRIPTION
dtruss prints details on process system calls. It is like a DTrace version of truss, and has been designed to be less intrusive than truss. Of particular interest is the elapsed times and on cpu times, which can identify both system calls that are slow to complete, and those which are consuming CPU cycles. Since this uses DTrace, only users with root privileges can run this command.

OPTIONS

-a  print all details

-b bufsize
    dynamic variable buffer size. Increase this if you notice dynamic variable drop errors. The default is "4m" for 4 megabytes per CPU.

-c  print system call counts

-d  print relative timestamps, us

-e  print elapsed times, us

-f  follow children as they are forked

-l  force printing of pid/lwpid per line

-L  don't print pid/lwpid per line

-n name
    examine processes with this name

-o  print on-cpu times, us

-s  print stack backtraces

-p PID
    examine this PID

-t syscall
    examine this syscall only

EXAMPLES

run and examine the "df -h" command
    # dtruss df -h

examine PID 1871
    # dtruss -p 1871

examine all processes called "tar"
    # dtruss -n tar

run test.sh and follow children
    # dtruss -f test.sh

run the "date" command and print elapsed and on cpu times,
    # dtruss -eo date

FIELDS

PID/LWPID
    Process ID / Lightweight Process ID

RELATIVE
    relative timestamps to the start of the thread, us (microseconds)

ELAPSD
    elapsed time for this system call, us

CPU on-cpu time for this system call, us

SYSCALL(args)
    system call name, with arguments (some may be evaluated)

DOCUMENTATION
See the DTraceToolkit for further documentation under the Docs directory. The DTraceToolkit docs may include full worked examples with verbose descriptions explaining the output.

EXIT
dtruss will run forever until Ctrl-C is hit, or if a command was executed dtruss will finish when the command ends.

AUTHOR
Brendan Gregg [Sydney, Australia]

SEE ALSO
procsystime(1M), dtrace(1M), truss(1)