Hello, I just ran across this document from Apple that describes the Thread affinity scheme that was added in Leopard. http://developer.apple.com/releasenotes/Performance/RN-AffinityAPI/
In its current form, and how orteds start the MPI ranks with exec, we can't use this, AFAIK. However, if someone cares, there might be a path for doing MPI process affinity on Mac OS X with quite a bit of work. Let me know if you have the time & interest, and I can explain my idea on how to do it. For the curious, here is the key text extracted from that document: "Generally, the affinity tag namespace is private to one task (process). However, a child process forked after its parent has made a THREAD_AFFINITY_POLICY call will share the affinity namespace of the parent process. This enables a family of forked processes to share an affinity namespace despite comprising separate tasks. Moreover, the forked child inherits the affinity tag of its parent. Hence, a parent can seed a number of child processes within an arbitrary organization of shared affinity sets. Note: affinity namespace inheritance is destroyed by the exec(3) system call, however." It's that last sentence about exec(3) that makes things (very) difficult for us. -- Tim Mattox, Ph.D. - http://homepage.mac.com/tmattox/ tmat...@gmail.com || timat...@open-mpi.org I'm a bright... http://www.the-brights.net/
