Re: [9fans] dtrace for plan 9

[dave.l@mac.com]

> Would this answer your question:
>   http://blogs.sun.com/jonh/entry/the_dtrace_deadman_mechanism

Well, it answers the question "What is the DTrace so-called deadman
mechanism?" I think.
That's a sort of part of a possible solution, which is OK.
To be pedantic, it's not a true deadman mechanism,
which operates at the point of failure (incapacity of the driver), not
when it's all over (death of the passengers).
What's described there is more like a pair of buffers at the end of
the crowded terminus station.

> Or are you literally trying to figure out the upper bound on the # of
> virtual instructions
> in a single probe?

Well, more importantly, the consequent real-time involved.
IOW: assuming you have some common sense (and a degree of chutzpah,
given the complexity of the solaris kernel),
and thus you have a reasonable idea about how long a time "too long"
is to be holding up your kernel,
how do you know whether a given D bytecode blob is gonna execute for
"too long" or not?

D