debugging and visualization
In lecture 7 we close chapter 2 on message-passing computing,
introducing the nonblocking MPI_Isend/MPI_Irecv
and corresponding MPI_Test and MPI_Wait.
As a motivation, we continue our exploration of
the computation/communication ratio of lecture 6,
asking the question: how many calculations can we
perform while sending a large matrix?
The program "cost_one_sr.c"
sets the time to send a 2520-by-2520 matrix
of doubles to about 5 seconds. In that time frame, the manager
can do one million additions of doubles,
as is done in "cost_i1sr.c".
The second part of this lecture concerns MPE,
a tool for a postmortem analysis based on trace files.
Bibliography