dtruss - process syscall details. Uses DTrace. dtruss [-acdeflhoLs] [-t syscall] { -p PID | -n name | command } 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 the root user or users with the dtrace_kernel privilege can run this command. Solaris stable - needs the syscall provider.

-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

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

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)

See the DTraceToolkit for further documentation under the Docs directory. The DTraceToolkit docs may include full worked examples with verbose descriptions explaining the output. dtruss will run forever until Ctrl-C is hit, or if a command was executed dtruss will finish when the command ends. Brendan Gregg [Sydney, Australia] procsystime(1M), dtrace(1M), truss(1)