slide 33 of 35

Implementation of PVM

• When a PE wants to send a message, it sends a parallel signal and waits for a barrier
• If a PE sees a signal pending, it joins the barrier
• Once all PEs have joined, the PEs vote on who wants to send a message
• In turn, each sender broadcasts its send opcode and then sends its message + tag (no source PE id!)
• Buffering problems are minimized by perfect global flow control