What does the system call "dup" do?
What is the difference between dup and dup2
I have a fair idea of what it does but I am confused when its coming down to the exact details...
Please help me!:confused: (2 Replies)
open, creat, read, write, lseek and close
Are they all primitive?
:confused:
*Another Question: is there a different between a system call, and an i/o system call? (2 Replies)
Hi,
I'm new to UNIX system calls. Can someone share your knowledge as to how exactly system calls should be executed?
Can they be typed like commands such as mkdir on the terminal itself? Also, are there any websites which will show me an example of the output to expect when a system call like... (1 Reply)
Hello,
how would i be able to call ps in C programming?
thanks,
---------- Post updated at 01:39 AM ---------- Previous update was at 01:31 AM ----------
here's the complete system call, ps -o pid -p %d, getpit() (2 Replies)
All,
Kindly let me know command which is used to trace the system calls on HP - UX server when an executable is run.
On Solaris we have TRUSS which does the need. On HP UX we have TUSC command which is a third party software. Currently this is not installed on my HP Server. If there... (3 Replies)
Discussion started by: helper
3 Replies
LEARN ABOUT MOJAVE
dtruss
dtruss(1m) USER COMMANDS 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
-W name
wait for a process matching 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 ver-
bose 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)version 0.80 Jun 17, 2005 dtruss(1m)