> Here is a patch to add the hooks I and ko1 talked about. (attached)
> And here is an extension library that provides prove points to dtrace,
> on top of the hooks. (http://github.com/yugui/vm_probes )
>
> What do you think?  ¨Βαξ γοννιτ τθπατγατταγθεδ
Isn't adding an event hook to OBJ_ALLOC kind of expensive? Does it
result in any slowdown?

(perhaps not useful, but
http://timetobleed.com/memprof-a-ruby-level-memory-profiler/ also
seems related.)

I'm all for the hooks to gc start and end.  That would be nice.

The hooks for thread init would be nice, though I'd still like to see
new threads receive the global hooks [1]

Rocky's also right that currently ruby doesn't (can't [?]) provide
coverage reports at the statements level--just at the file/line
level--it would be kind to allow for more granularity, though not
totally related to your patch (something like [2] might do the trick).

Regards.
-r
[1] http://redmine.ruby-lang.org/issues/show/2012
[2] http://github.com/rocky/rb-threadframe/blob/master/threadframe-ruby-1.9.patch