[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



More information about the Beowulf mailing list