Message passing support on StarT-Voyager

Abstract

No single message passing mechanism can efficiently support all types of communication that commonly occur in most parallel or distributed programs. MIT's StarT-Voyager, a hybrid message passing/shared memory parallel machine, provides four message passing mechanisms to achieve high performance over a wide spectrum of communication types and sizes. Hardware and address translation enforced protection allows direct user-level access to message passing facilities in a multiuser environment. StarT-Voyager's protection scheme improves upon past designs by not requiring strictly synchronized gang-scheduling, and by supporting non-monolithic protection domains. To minimize the development effort and cost, the machine is designed to use unmodified commercial PowerPC 604-based SMP systems as the building block. A Network End-point Subsystem (NES) card which plugs into one of each SMP's processor card slots provides the interface to Arctic, a low-latency, highbandwidth network developed at MIT. This paper describes StarT-Voyager's message passing mechanisms and their predicted performance.

Flexible architectural support for fine-grain scheduling

“…Finally, in ADM messages are sent to virtual threads, not physical thread contexts, allowing the OS to perform thread migration and more flexible scheduling. StarT-Voyager [5] implements user-level message passing by exposing memory-mapped send and receive queues that can overflow to main memory, but these memory-mapped queues entail additional overheads. The J-Machine [40] and M-Machine [35] also include a set of flexible messaging mechanisms suitable for fine-grain asynchronous communication, but unlike these message-driven architectures, for which messaging is the main means of communication, we advocate introducing messaging support in a sharedmemory CMP.…”

Beyond Dataflow

“…Thus, PowerPC 620 was planned in StarT-ng machine (Ang et al, 1995) but the architecture was redesigned once again -this time around a 32-bit PowerPC 604 -and was called StarTVoyager machine (Ang et al, 1996). This machine, however, bears little resemblance to the original StarT architecture and no similarity to Monsoon.…”

Micro-architectures of high performance, multi-user system area network interface cards

“…This is becoming increasingly important as System Area Networks are incorporated into new I/O standards, such as Infiniband [11]. A general approach is to have each node in the network support multiple private message queues allocating a unique set to each job that requires user-level, high performance communication [9,8,10,3].…”