Comment by gsnedders
8 years ago
It's not totally standalone (it has kernel components, for example), but yes, it's clearly something far easier to suddenly drop.
8 years ago
It's not totally standalone (it has kernel components, for example), but yes, it's clearly something far easier to suddenly drop.
I think the point is you can rip the kernel components out, and the (non-Dtrace using dev) user doesn't notice. Whereas removing a filesystem driver leaves users without their data.
Mojave drops support for DTrace probes in Instruments, so this process may already have begun.
Very few people internally to Apple cared about DTrace, and the person who was primarily responsible for evangelizing it left that particular role years ago. DTrace support has been slowly degrading over time (to the point that Apple has ended up shipping DTrace scripts on the system that do nothing but spew errors if you try and use them, as the probes changed and nobody updated the scripts).
It's a shame, because DTrace is cool and very powerful, but it seems almost nobody bothered to actually learn how to use it or cared about supporting it.
I've been using DTrace on High Sierra a bit for the past few months, and it has been working fine for me. I'm writing my own scripts though. I did notice that the sample scripts often did not work, but did not think that meant much.
DTrace is definitely cool and powerful. I'm surprised to hear that few people at Apple cared about it - I'd have thought it was an essential tool for them to solve certain kinds of problems. It's funny, because the tool itself is relatively simple. It seems to me that most of the knowledge needed to use it effectively is an understanding of the code being instrumented, rather than of DTrace itself. Hopefully the sample scripts degrading does not foreshadow the probes themselves degrading too.
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Really? Is there a replacement?
Instruments in Xcode 10 has a new way of constructing "custom instruments". I haven't looked into the details though, so I don't know how much of the old DTrace stuff can be replicated.