Parallel Programming Guide for HP-UX Systems

MPI

Tuning

Chapter 268

Figure 2-2 Multiple network interfaces

Host0 processes with rank 0 - 15 communicate with processes with

rank 16 - 31 through shared memory (shmem). Host0 processes also communicate through the

host0-ethernet0 and the host0-ethernet1 network interfaces with host1 processes.

Processor subscription

Subscription refers to the match of processors and active processes on a host. Table 2-7 lists

possible subscription types.

Table 2-7 Subscription types

Subscription type Description

Under subscribed More processors than active

processes

Fully subscribed Equal number of processors and

active processes

host0

host1

shmem

Ranks 0 - 15

Ranks 16 - 31

Ranks 48 - 63

Ranks 32 - 47

ethernet0

ethernet1

ethernet0

ethernet1