dtrace discuss - Oct 2006 - how to watch kmem_init() during boot time

Hi,

Following "anonymous tracing" chapter, I wanna trace kmem_init(), but
after reboot, I can''t get anything, why?

Here is my short script kmem_init.d:

#!/usr/sbin/dtrace -s

fbt::kmem_init:entry
{
      stack();
}


then I just use:
#dtrace -AFs kmem_init.d
#reboot
#dtrace -ae
< got nothing here>



Thanks,
-Alex
 
 
This message posted from opensolaris.org

Hey Alex,

kmem_init() is called before DTrace is initialized (the dtrace kernel module
makes use of kmem_alloc()). You can use kmdb to stop in kmem_init() if you
like.

Adam

On Mon, Oct 23, 2006 at 03:52:56AM -0700, Alex Peng
wrote:
> Hi,
> 
> Following "anonymous tracing" chapter, I wanna trace kmem_init(),
but after reboot, I can''t get anything, why?
> 
> Here is my short script kmem_init.d:
> 
> #!/usr/sbin/dtrace -s
> 
> fbt::kmem_init:entry
> {
>       stack();
> }
> 
> 
> then I just use:
> #dtrace -AFs kmem_init.d
> #reboot
> #dtrace -ae
> < got nothing here>
> 
> 
> 
> Thanks,
> -Alex
>  
>  
> This message posted from opensolaris.org
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org
-- 
Adam Leventhal, Solaris Kernel Development       http://blogs.sun.com/ahl

Thanks Adam, I realized this just after I posted it.  :)  Then what''s
the boundry during boot, i.e.  before which function DTrace can''t help,
after which function DTrace could work?

-Alex
 
 
This message posted from opensolaris.org

Hey Alex,

It looks like the first probes we hit when we start to configure devices:

# dtrace -A -F -xbufsize=1k -xbufpolicy=fill -n ''fbt:::{ stack()
}''
...
# reboot
...
# dtrace -a
CPU FUNCTION
  0  -> xc_sync
              unix`dtrace_xcall+0x7e
              dtrace`dtrace_state_go+0x42f
              dtrace`dtrace_attach+0x487
              genunix`devi_attach+0x87
              genunix`attach_node+0x123
              genunix`i_ndi_config_node+0xd9
              genunix`i_ddi_attachchild+0x67
              genunix`devi_attach_node+0xcc
              genunix`config_immediate_children+0xf2
              genunix`devi_config_common+0x9f
              genunix`mt_config_thread+0x5c
              unix`thread_start+0x8
...

Hope that helps.

Adam

On Mon, Oct 23, 2006 at 07:22:22PM -0700, Alex Peng
wrote:
> Thanks Adam, I realized this just after I posted it.  :)  Then
what''s the boundry during boot, i.e.  before which function DTrace
can''t help, after which function DTrace could work?
> 
> -Alex
>  
>  
> This message posted from opensolaris.org
> _______________________________________________
> dtrace-discuss mailing list
> dtrace-discuss at opensolaris.org
-- 
Adam Leventhal, Solaris Kernel Development       http://blogs.sun.com/ahl

Sure, this helps.   Why not state it clearly somewhere, either in your blog (how
about this title "what can DTrace do at early boot time?") or ...?
I searched around, it seems several other people are asking "anonymous
tracing" questions, so it''s better to give a clear boundry.

Again, your oneline script is wonderful.

Thanks,
-Alex
 
 
This message posted from opensolaris.org