ParaStation MPI offers a feature called "TCP bypass", enabling applications based on TCP to use the efficient p4sock protocol. The data will be redirected within the kernel to the p4sock protocol. No modifications to the application are necessary!
To automatically configure the TCP bypass during ParaStation MPI startup, insert a line like
Env PS_TCPFirstAddress-LastAddress
in the p4sock-section of the configuration file
parastation.conf, were
FirstAddress and
LastAddress are the first and last IP
addresses for which the bypass should be configured.
To enable the bypass for a pair of processes, the library
libp4tcp.so, located in the directory
/opt/parastation/lib64 must be preloaded by
both processes using:
export LD_PRELOAD=/opt/parastation/lib64/libp4tcp.so
For parallel and serial tasks launched by ParaStation MPI, this environment variable is exported to all processes by default. Please refer to ps_environment(5).
It's not recommended to insert
libp4tcp.so in the global preload
configuration file /etc/ld.so.preload, as this
may hang connections to daemon processes started up before the
bypass was configured.
See also p4tcp(8).