Friday 7 October 2011

DTrace update...sort of.

Just pushed out a minor update to fix a problem on SLES11 systems.

Its a few days after OracleWorld and the Dtrace announcement and
people may bump into this blog because of Adam Leventhals post.

So, just a few words on the Dtrace/Linux port which has been available
for 2+ years now.

From what I understand Oracle are planning to port Dtrace to Linux, despite
this release being available. That is a *good* thing, because it
means a 4th (to my knowledge) port of Dtrace. First was FreeBSD, then
there was MacOSX, then there was this Linux/Dtrace.

I have learnt a lot from reviewing and understanding the differing
implementations. My work on Dtrace is "not-bad" if I am going to self-rate.
It is mired in details to do with multiple kernel support and lack of
source code modifications to a kernel: Dtrace/Linux is simply a loadable
kernel module.

Oracle will pick up the latest code of Dtrace from the Solaris area,
and will have some fiddliness to insert into Linux. They
pay their employees to do this - and thats great. They can change
the kernel source code, and provide a value added kernel (just
like Google does with Android and all the other hardware/software
vendors who leverage Linux).

This will presumably give them a competitive advantage: for those
customers who want Dtrace, then Oracle potentially looks attractive.
Many people in the Linux community will write-off Oracle as "not team
players". That happened before, with Sun. This leads to healthy,
sometimes silly but entertaining debates on the interweb.

Since Oracle is not using this port of Dtrace as the basis of their
work, does not imply the death of this project. The likelihood is
more people will stumble upon it and lead to more support questions or
requests to finish or fix issues.

Oracle could add new providers to the kernel - and this release of
Dtrace will not be able to match these, without patching kernel source.
I dont know how this will evolve. Maybe Oracle will show us what to do;
maybe there will be sufficient impetus to get dtrace into the master Linux
kernel, but I doubt that will happen.

The GPL vs CDDL debate still rages. I've written numerous times on
my opinion of the debate (namely, I dont have an opinion!).

So continue to try/play with Dtrace.

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