Brad unfortunately figured out I had done something to annoy the gods of
mercurial and the repository below didn't contain all the changes
advertised (and in fact didn't work). I've since rebuilt the repository
and verified it works now. I'd recommend deleting your existing clones of
the repository below and starting over.
Sorry about that,
Brian
On Wed, 11 Jun 2008, Brian Barrett wrote:
Did anyone get a chance to test (or think about testing) this? I'd like to
commit the changes on Friday evening, if I haven't heard any negative
feedback.
Brian
On Jun 9, 2008, at 8:56 PM, Brian Barrett wrote:
Hi all -
Per the RFC I sent out last week, I've implemented a revised behavior of
the memory hooks for high speed networks. It's a bit different than the
RFC proposed, but still very minor and fairly straight foward.
The default is to build ptmalloc2 support, but as an almost complete
standalone library. If the user wants to use ptmalloc2, he only has to add
-lopenmpi-malloc to his link line. Even when standalone and openmpi-malloc
is not linked in, we'll still intercept munmap as it's needed for mallopt
(below) and we've never had any trouble with that part of ptmalloc2 (it's
easy to intercept).
As a *CHANGE* in behavior, if leave_pinned support is turned on and there's
no ptmalloc2 support, we will automatically enable mallopt. As a *CHANGE*
in behavior, if the user disables mallopt or mallopt is not available and
leave pinned is requested, we'll abort. I think these both make sense and
are closest to expected behavior, but wanted to point them out. It is
possible for the user to disable mallopt and enable leave_pinned, but that
will *only* work if there is some other mechanism for intercepting free
(basically, it allows a way to ensure your using ptmalloc2 instead of
mallopt).
There is also a new memory component, mallopt, which only intercepts munmap
and exists only to allow users to enable mallopt while not building the
ptmalloc2 component at all. Previously, our mallopt support was lacking in
that it didn't cover the case where users explicitly called munmap in their
applications. Now, it does.
The changes are fairly small and can be seen/tested in the HG repository
bwb/mem-hooks, URL below. I think this would be a good thing to push to
1.3, as it will solve an ongoing problem on Linux (basically, users getting
screwed by our ptmalloc2 implementation).
http://www.open-mpi.org/hg/hgwebdir.cgi/bwb/mem-hooks/
Brian
--
Brian Barrett
Open MPI developer
http://www.open-mpi.org/
