[Beowulf] Re: Re: Home beowulf - NIC latencies

Isaac Dooley idooley at isaacdooley.com
Fri Feb 11 12:39:29 PST 2005

>True. I always wonder what the low-CPU-usage-advocates want the MPI 
>process to do while i.e. an MPI_Send() is executed. 
They don't want the process to do anything when the call MPI_Send, 
however carefully using asynchronous or non-blocking messaging ideally 
would not use the CPU. Using MPI_ISend() allows programs to not waste 
CPU cycles waiting on the completion of a message transaction. This is 
critical for some tightly coupled fine grained applications. Also it 
allows for overlapping computation and communication, which is beneficial.

Isaac Dooley

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