about systemtap test!

about systemtap test!

[Kevin Jia]

Two problems:

1. I use the follow program for testing:

    probe kernel.function("sys_open")
{
    printf("%s(%d)open(%s)\n", execname(), pid(), argstr)
}
probe timer.ms(4000)
{
    exit()
}

   the result looks like this:

    udev(10266) open()
    udev(10266) open()
    udev(10266) open()
    nifd(1383) open()
    ...
So why have not anything include the open's parenttheses? And what
meaning of the "argstr"?

2. how use systemtap probes the watchpoint? Can you give me some examples?

thanks.

RE: about systemtap test!

[Stone, Joshua I]

Kevin Jia wrote:
> So why have not anything include the open's parenttheses? And what
> meaning of the "argstr"?

In your script, argstr has not been set to anything.  It is being
inferred as a string from the format you gave, and the default value of
a string is "".  If instead you use the syscall tapset to probe
syscall.open, then a formatted argstr will be built for you.  The argstr
gives a string representation of all of the parameters to the syscall.

> 2. how use systemtap probes the watchpoint? Can you give me some
> examples? 

I'm not sure what you're asking here.  The SystemTap website has a few
architecture documents that might give the answer you're looking for.
If not, please try to rephrase your question.


Josh Stone