DTrace real port

Posted Aug 9, 2007 10:25 UTC (Thu) by man_ls (guest, #15091)
In reply to: Drag-n-drop DTrace into Linux Kernel? by pr1268
Parent article: On DTrace envy

I'm surprised that nobody has asked the question, so it is probably an obvious stupidity. Anyway there it goes.

Why bother to port? Why not reimplement everything (including the kernel modules) and put it under GPLv2? Building a compatible implementation shouldn't require that much effort, even to the point where DTrace scripts can be shared (that is, those which are not too tightly coupled to Solaris internals).

DTrace real port

Posted Aug 9, 2007 15:47 UTC (Thu) by bcantrill (guest, #31087) [Link] (1 responses)

Good luck with that.

DTrace real port

Posted Aug 10, 2007 23:13 UTC (Fri) by man_ls (guest, #15091) [Link]

Is there any specific problem you see with this approach? Not that it is an easy task, but after all there is a working implementation with source code to study. It would probably be easier than working around the limitations you people have exposed in SystemTap, wouldn't it?

dtrace clone

Posted Aug 10, 2007 14:48 UTC (Fri) by fuhchee (guest, #40059) [Link] (4 responses)

There are several obstacles. Rewriting the code is a relatively small part. Merging upstream is huge and controversial. There may also be legal (patent) barriers.

dtrace clone

Posted Aug 10, 2007 23:09 UTC (Fri) by man_ls (guest, #15091) [Link] (3 responses)

Merging upstream has to be done with SystemTap too. Is there any reason why it would be harder with a dtrace clone?

And patent trouble has not stopped kernel developers before...

dtrace clone

Posted Aug 11, 2007 20:53 UTC (Sat) by fuhchee (guest, #40059) [Link]

> Merging upstream has to be done with SystemTap too.

Not as much as one might think. Systemtap relies only on existing
externalized kernel interfaces and hooks - no changes just on our
account. That's not to say it wouldn't be nice to get some extra
interfaces/hooks, or to offload some version drift maintenance to other
folks. It means that we can work toward their development and upstream
inclusion gradually, without blocking the rest of the work.

dtrace clone

Posted Aug 11, 2007 22:09 UTC (Sat) by dlang (guest, #313) [Link] (1 responses)

please name anything in the kernel that has been put in if there is any doubt about the legality of it.

the license and patent status of dtrace is very much a reason for it not being considered (in fact, due to these issues most of the kernel developers don't even look at it to avoid any accusations of them being tainted)

dtrace clone

Posted Aug 12, 2007 12:13 UTC (Sun) by man_ls (guest, #15091) [Link]

As you probably know, any non-trivial piece of code probably infringes on a lot of patents. That hasn't stopped kernel developers from improving the kernel, and rightly so. Maybe the situation with specific patents is different.