[dtrace-discuss] dtrace wired issue

Aubrey Li
Mon, 14 Jan 2008 13:26:49 -0000

On Jan 14, 2008 9:22 PM, James C. McPherson <James.McPherson at sun.com>
wrote:
> Aubrey Li wrote:
> > On Jan 14, 2008 8:52 PM, Sean McGrath - Sun Microsystems Ireland
> > <sean.mcgrath at sun.com> 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 ?
> >
> > # psrinfo -vp
> > The physical processor has 2 virtual processors (0 1)
> >   x86 (GenuineIntel 10674 family 6 model 23 step 4 clock 2400 MHz)
> >         Intel(r) CPU                  @ 2.40GHz
> >
> > So, I failed to understand the modules loading needs 4 minutes.
>
>
> If you run "dtrace -l" with no args, *every* single loadable
> module on the system will be loaded, interrogated by dtrace
> and then unloaded if possible.
>
> All those attach()es and detach()es need time, as does the
> probe collation.
>
So may I ask, how long "dtrace -l" get response on your system?
And how fast the cpu speed on your system?

4 minutes, it is absolutely acceptable for me.

Thanks,
-Aubrey