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Re: extent-patch and overview of what is supposed to follow

On Wed, Apr 06, 2011 at 04:39:04PM +0100, Mindaugas Rasiukevicius wrote:
> No, I do not see the need to collect statistics about every allocation,
> e.g. load of temporary buffer, string, whatever allocations/frees.

Besides which, DTrace can *do* this.  And, contrary to what I've seen in
this thread, there is no great mystery about how to implement DTrace
support for more architectures.  We did the i386 implementation with no
more documentation than what Sun supplies and the public discussions of
how it had been ported to FreeBSD.

On the other hand, someone highly skilled will need to do the work --
someone familiar both with the architecture for which support is being
implemented and with our kernel as a whole, and willing to read and
understand the DTrace code with the help of Sun's documentation.  We
(Coyote Point) can't do that right now, because our people with the
right skills are tied up elsewhere.  However, Darran Hunt, who did the
original work for us, would likely be more than glad to help anyone
seriously interested in implementing it on other architectures.

I submit that DTrace can do what the majority of our existing ad-hoc
debugging and diagnostic frameworks can do, and much more.  Developers
with the skills to devise and implement new such code might find that
for the same amount of work, a greater payback came from working on
DTrace instead.


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