On Tue, 04 Aug 2009 13:18:18 PDT, Andrew Morton said:

> As usual, we're adding tracepoints because we feel we must add
> tracepoints, not because anyone has a need for the data which they
> gather.

One of the strong points of the Solaris 'dtrace' is that the kernel comes
pre-instrumented with zillions of tracepoints, including a lot that don't
seem to have very much application - just so they're already in place in
case you hit some weird issue and need the tracepoint for an ad-crock dtrace
script to debug something.  So when I'm trying to diagnose why my backup
server suddenly got sluggish 3 terabytes into a 5 terabyte backup, and it
looks like some weird fiberchannel issue, I can collect data without having
to reboot to install a tracepoint (which would lose the backup, and possibly
reset the issue or otherwise make it go into hiding).

Just sayin'. :)