[dtrace-discuss] dtrace wired issue

Adam Leventhal
Mon, 14 Jan 2008 16:44:17 -0000

On Mon, Jan 14, 2008 at 12:52:55PM +0000, Sean McGrath - Sun Microsystems
Ireland wrote:
> Aubrey Li stated:
> < Every first time to run dtrace command after the system boot up,
> < It takes a very long time to get response.
> < But the second time is OK, as follows:
> <
> < # time dtrace -l > /dev/null
> <
> < real    4m8.011s
> < user    0m0.116s
> < sys     0m2.420s
>
>   This first time is probably when the kernel is loading the dtrace
modules.
>   Though still seems slow, 4 minutes.
>     What kind of system (cpu speed etc) is the machine ?

The first time DTrace is loaded it needs to uncompress the CTF (type)
information for all of the currently loaded kernel modules which can take
quite a while. Four minutes does seem a bit excessive. Are you seeing any
swapping?

Adam

--
Adam Leventhal, FishWorks                        http://blogs.sun.com/ahl