At 03:43 AM 6/6/2006, Michael S. Tsirkin wrote: >Quoting r. Talpey, Thomas <[EMAIL PROTECTED]>: >> Semantically, the provider is not required to provide any such flow control >> behavior by the way. The Mellanox one apparently does, but it is not >> a requirement of the verbs, it's a requirement on the upper layer. If more >> RDMA Reads are posted than the remote peer supports, the connection >> may break. > >This does not sound right. Isn't this the meaning of this field: >"Initiator Depth: Number of RDMA Reads & atomic operations >outstanding at any time"? Shouldn't any provider enforce this limit?
The core spec does not require it. An implementation *may* enforce it, but is not *required* to do so. And as pointed out in the other message, there are repercussions of doing so. I believe the silent queue stalling is a bit of a time bomb for upper layers, whose implementers are quite likely unaware of the danger. I greatly prefer an implementation which simply sends the RDMA Read request, resulting in a failed (but unblocked!) connection. Silence is a very dangerous thing, no matter how helpful the intent. Tom. _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
