****************************************************************************** GPI-2 http://www.gpi-site.com Version: 1.0.1 Copyright (C) 2013 Fraunhofer ITWM ****************************************************************************** 1. INTRODUCTION =============== GPI-2 is the second generation of GPI (www.gpi-site.com). GPI-2 implements the GASPI specification (www.gaspi.de), an API specification which originates from the ideas and concepts of GPI. GPI-2 is an API for asynchronous communication. It provides a flexible, scalable and fault tolerant interface for parallel applications. 2. INSTALLATION =============== The easiest way to install GPI-2 is by using the install.sh script. The default settings install GPI-2 under /opt/GPI2/. This location can be easily modified by passing the location with the -p option to the install script. For example, ./install.sh -p /prog/GPI2 installs GPI-2 under /prog/GPI2 instead of under the default location. GPI-2 requires the libibverbs from the OFED stack. You can pass the path of your OFED installation to the install script using the option (-o) for that, in case the install script is not able to find it: ./install.sh -o Requirements: ------------- The current version of GPI-2 has the following requirements. Software: - libibverbs (Verbs library from OFED). - ssh server running on compute nodes (requiring no password). Hardware: - Infiniband or RoCE devices. 3. BUILDING GPI-2 ================= You can build GPI2 on your own. There are the following make targets: all - Build everything gpi - Build the GPI-2 library (including debug version) mic - Build the GPI-2 library for the MIC tests - Build provided tests docs - Generate documentation (requires doxygen) clean - Clean-up 4. BUILDING GPI-2 APPLICATIONS ============================== GPI-2 provides two libraries: libGPI2.a and libGPI2-dbg.a. The libGPI2.a aims at high-performance and is to be used in production whereas the libGPI2-dbg.a provides a debug version, with extra parameter checking and debug messages and is to be used to debug and during development. 5. RUNNING GPI-2 APPLICATIONS ============================= The gaspi_run utility is used to start and run GPI-2 applications. A machine file with the hostnames of nodes where the application will run, must be provided. For example, to start 1 process per node (on 4 nodes), the machine file looks like: node01 node02 node03 node04 Similarly, to start 2 processes per node (on 4 nodes): node01 node01 node02 node02 node03 node03 node04 node04 The gaspi_run utility is invoked as follows: gaspi_run -m [OPTIONS] IMPORTANT: The path to the program must be the full path and that same path must exist on all nodes where the program should be started. The gaspi_run utility has the following further options [OPTIONS]: -b Use a different binary for first node (master). The master (first entry in the machine file) is started with a different application than the rest of the nodes (workers). -N Enable NUMA for processes on same node. With this option it is only possible to start the same number of processes as NUMA nodes present on the system. The processes running on same node will be set with affinity to the proper NUMA node. -n Start as many from machine file. This option is used to start less processes than those listed in the machine file. -d Run with GDB (debugger) on master node. With this option, GDB is started in the master node, to allow debugging the application. -h Show help. 5. THE GASPI_LOGGER =================== The gaspi_logger utility is used to view the output from all nodes except the master node (rank 0). The gaspi_logger is started, on another session, on the master node. The output of the application, when called with gaspi_printf, will be redirected to the gaspi_logger. Other I/O routines (e.g. printf) will not. 6. GPI-2 WITH CO-PROCESSOR (INTEL XEON PHI) ========================================== GPI-2 can be used with the Intel Xeon Phi (MIC) where the MIC is used as one node (running possibly more than one GPI-2 process). To use GPI-2 on the MIC, you need to compile it using the Intel compiler with the -mmic option. The Makefile includes a build target mic for that end but this build target is not used by the installation script. After successful compilation, GPI-2 for the MIC can be found under lib64/mic. If you are having problems with the compilation, make sure the OFED_PATH in src/Makefile is setup correctly. Assuming that the MIC(s) is set up properly, GPI-2 requires: - ssh connectivity (requiring no password) - grouping of local host and MIC(s) by using the tool micctrl micctrl --initdefaults micctrl --addbridge=br0 --type=internal --ip=172.31.1.254 micctrl --network=static --bridge=br0 --ip=172.31.1.1 where for instance, mic0: 172.31.1.1, mic1: 172.31.1.2 etc. The MIC must be visible to the whole cluster network. For instance, if your cluster network is 192.168.1.0 on eth0 and you want to map mic0 to 192.168.1.100 do: iptables -t nat -A PREROUTING -d 192.168.1.100 -i eth0 -j DNAT --to-destination 172.31.1.1 iptables -t nat -A POSTROUTING -s 172.31.1.1 -o eth0 -j SNAT --to-source 192.168.1.100 After setup, the MIC hostname can simply be added to the machinefile and be used as another host. 7. TROUBLESHOOTING ================== If you're having troubles when building GPI-2, make sure you have the OFED stack correctly installed and running. You can change the OFED path in the Makefile in the source directory (src) to the correct path in your system. 8. UP COMING FEATURES ===================== GPI-2 is on-going work and more features are still to come. Here are some that are in our roadmap: - fully asynchronous collectives - include the support for GPU memory (available but not yet integrated) - threads integration - support to add spare nodes (fault tolerance) - better debugging possibilities 9. MORE INFORMATION =================== For more information, check the GPI-2 website: www.gpi-site.com