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dtruss(1)                       USER COMMANDS                      dtruss(1)




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 ver-
       sion 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 (microsec-
              onds)

       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  direc-
       tory. The DTraceToolkit docs may include full worked examples with ver-
       bose descriptions explaining the output.


EXIT

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


AUTHOR

       Brendan Gregg [Sydney, Australia]


SEE ALSO

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




version 0.80                     Jun 17, 2005                       dtruss(1)

Mac OS X 10.6 - Generated Thu Sep 17 20:07:30 CDT 2009
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