Not much to report this week on DTrace - the pid provider seems pretty
stable, and a number of Linux versioning issues were resolved. (I believe
theres one more to fix, reported on Centos).
Using the pid provider is interesting - theres some fixes needed for some
platforms, because some rtld (runtime linker) symbols cause an error
to be generated - that just needs a little debugging; but its annoying
that of the thousands of symbols being examined, only one is needed to cause
dtrace to give up.
I also encountered a few 'too many probes in use' kind of error, e.g.
when trying to instrument all functions in all shared libraries - its
easy to blast past the 250,000 max probe limitation. Probably could
do with looking at the fasttrap tracepoint data structure to see if its
possible to shave a few bytes off and increase the limit. (Solaris allows
the limit to be changed at start time, and Linux does too via
the insmod/modprobe "modprobe dtracedrv fasttrap_max=nnnn").
Its probably time to relook at the static probes and continue
working through the Solaris providers, to insert the missing probes.
But a lot of people are using dtrace, and I hope, learning about the
kernel or optimising programs which one day, I may be using.