Brendan Gregg's site (and book) is probably the best starting point (he was involved in DTrace work & rollout 20 years ago when at Sun) and was/is instrumental in pushing eBPF in Linux even further than DTrace ever went:
Edit: We actually went into much more specific detail on eBPF/BCC in contrast to DTrace a few weeks after the 20th anniversary podcast.[1]
What I loved about DTrace was that once it was out, even in beta, it was pretty complete and worked - all the DTrace ports that I've tried, including on Windows (!) a few years ago were very limited or had some showstopper issues. I guess eBPF was like that too some years ago, but by now it's pretty sweet even for more regular consumer who don't keep track of its development.
Edit: Oh, wasn't aware of the timeline, I may have some dates (years) wrong in my memory
For sure. Different systems, different times.
>rather than one eclipsing the other.
It does seem that DTrace has been eclipsed though, at least in Linux (which runs the vast majority of the world's compute). Is there a reason to use DTrace over eBPF for tracing and observability in Linux?
>There are certainly many things that DTrace can do that eBPF/BCC cannot
This may be true, but that gap is closing. There are certainly many things that eBPF can do that DTrace cannot, like Cilium.
Back when I tried to build xcapture with DTrace, I could launch the script and use something like /pid$oracle::func:entry/ but IIRC the probe was attached only to the processes that already existed and not any new ones that were started after loading the DTrace probes. Maybe I should have used some lower level APIs or something - but eBPF on Linux automatically handles both existing and new processes.
Without knowing your particular case, DTrace does too - it’d certainly be tricky to use if you’re trying to debug software that “instantly crashes on startup” if it couldn’t do that. “execname” (not “pid”) is where I’d look, or perhaps that part of the predicate is skipable; regardless, should be possible.
Execname is a variable in DTrace and not a probe (?), so how would it help with automatically attaching to new PIDs? Now that I recall more details, there was no issue with statically defined kernel "fbt" probes nor "profile", but the userspace pid one was where I hit this limitation.
You're correct, and I may have provided "a solution" to a misunderstanding of your problem - I don't think the "not matching new procs/pids" is inherent in DTrace, so indeed you might have run into an implementation issue (as it was 15 years ago). I misunderstood you as perhaps using a predicate matching a specific pid; my fault.