README.SHMEM.hotspotinc

Communication Motif: hotspotinc

Description:

Unstructured, irregular (for instance data analytics applications based
on graphs with low/no-locality) applications typically have random,
small message communications. However, for some applications, inputs or
problem configurations, the more uniform nature of the random accesses
can change to become more localized. In the hotspotinc motif, we have
developed a sparse, randomized communication pattern that first randomly
selects a remote communication partner (weighted towards a "hot spot"
node) and then a random address on the remote side. Each message
performs an atomic increment on the remote communication partner.

A second use of the hotspotinc benchmark can be to introduce randomized,
with hotspot, small messsage background traffic to a machine/simulator
for analysis. Such patterns are representative of large collections of
small jobs executing in a full machine (where network congestion and 
runtime variance is experienced), or patterns of I/O metadata querying
and small random access.