Re: [OMPI devel] OMPI OpenIB Credit Schema breaks Chelsio HW

[Steve Wise]

Jeff Squyres wrote: On Mar 10, 2008, at 9:57 AM, Steve Wise wrote: A single PP QP might be fine for now, and chelsio's next-gen part will support SRQs and not have this funky issue. Good! But why use such a large buffer size for a single PP QP? Why not use something around 16KB? You can do that, but you'll also need to make the max_send_size be 16kb (and therefore ob1 will switch to rendezvous protocol above that size). See our paper on the long message protocol that OMPI uses -- the minimum "large" message size was specifically designed to be kinda big so that we could do some send/recv to offset the registration penalty of pinning user's large buffers. Does OMPI do lazy dereg to maintain a cache of registered user buffers?