Product specifications
Table Of Contents
- Table of Contents
- 1 Introduction
- 2 Feature Overview
- 3 Step-by-Step Cluster Setup and MPI Usage Checklists
- 4 InfiniPath Cluster Setup and Administration
- Introduction
- Installed Layout
- Memory Footprint
- BIOS Settings
- InfiniPath and OpenFabrics Driver Overview
- OpenFabrics Drivers and Services Configuration and Startup
- Other Configuration: Changing the MTU Size
- Managing the InfiniPath Driver
- More Information on Configuring and Loading Drivers
- Performance Settings and Management Tips
- Host Environment Setup for MPI
- Checking Cluster and Software Status
- 5 Using QLogic MPI
- Introduction
- Getting Started with MPI
- QLogic MPI Details
- Use Wrapper Scripts for Compiling and Linking
- Configuring MPI Programs for QLogic MPI
- To Use Another Compiler
- Process Allocation
- mpihosts File Details
- Using mpirun
- Console I/O in MPI Programs
- Environment for Node Programs
- Environment Variables
- Running Multiple Versions of InfiniPath or MPI
- Job Blocking in Case of Temporary InfiniBand Link Failures
- Performance Tuning
- MPD
- QLogic MPI and Hybrid MPI/OpenMP Applications
- Debugging MPI Programs
- QLogic MPI Limitations
- 6 Using Other MPIs
- A mpirun Options Summary
- B Benchmark Programs
- C Integration with a Batch Queuing System
- D Troubleshooting
- Using LEDs to Check the State of the Adapter
- BIOS Settings
- Kernel and Initialization Issues
- OpenFabrics and InfiniPath Issues
- Stop OpenSM Before Stopping/Restarting InfiniPath
- Manual Shutdown or Restart May Hang if NFS in Use
- Load and Configure IPoIB Before Loading SDP
- Set $IBPATH for OpenFabrics Scripts
- ifconfig Does Not Display Hardware Address Properly on RHEL4
- SDP Module Not Loading
- ibsrpdm Command Hangs when Two Host Channel Adapters are Installed but Only Unit 1 is Connected to the Switch
- Outdated ipath_ether Configuration Setup Generates Error
- System Administration Troubleshooting
- Performance Issues
- QLogic MPI Troubleshooting
- Mixed Releases of MPI RPMs
- Missing mpirun Executable
- Resolving Hostname with Multi-Homed Head Node
- Cross-Compilation Issues
- Compiler/Linker Mismatch
- Compiler Cannot Find Include, Module, or Library Files
- Problem with Shell Special Characters and Wrapper Scripts
- Run Time Errors with Different MPI Implementations
- Process Limitation with ssh
- Number of Processes Exceeds ulimit for Number of Open Files
- Using MPI.mod Files
- Extending MPI Modules
- Lock Enough Memory on Nodes When Using a Batch Queuing System
- Error Creating Shared Memory Object
- gdb Gets SIG32 Signal Under mpirun -debug with the PSM Receive Progress Thread Enabled
- General Error Messages
- Error Messages Generated by mpirun
- MPI Stats
- E Write Combining
- F Useful Programs and Files
- G Recommended Reading
- Glossary
- Index
IB6054601-00 H B-1
B Benchmark Programs
Several MPI performance measurement programs are installed from the
mpi-benchmark RPM. This appendix describes these benchmarks and how to
run them. These programs are based on code from the group of Dr. Dhabaleswar
K. Panda at the Network-Based Computing Laboratory at the Ohio State
University. For more information, see: http://mvapich.cse.ohio-state.edu/
These programs allow you to measure the MPI latency and bandwidth between
two or more nodes in your cluster. Both the executables, and the source for those
executables, are shipped. The executables are shipped in the mpi-benchmark
RPM, and installed under /usr/bin. The source is shipped in the mpi-devel
RPM and installed under /usr/share/mpich/examples/performance.
The following examples are intended to show only the syntax for invoking these
programs and the meaning of the output. They are not representations of actual
InfiniPath performance characteristics.
Benchmark 1: Measuring MPI Latency Between
Two Nodes
In the MPI community, latency for a message of given size is the time difference
between a node program’s calling MPI_Send and the time that the corresponding
MPI_Recv in the receiving node program returns. The term latency, alone without
a qualifying message size, indicates the latency for a message of size zero. This
latency represents the minimum overhead for sending messages, due to both
software overhead and delays in the electronics of the fabric. To simplify the
timing measurement, latencies are usually measured with a ping-pong method,
timing a round-trip and dividing by two.
The program osu_latency, from Ohio State University, measures the latency for
a range of messages sizes from 0 to 4 megabytes. It uses a ping-pong method, in
which the rank zero process initiates a series of sends and the rank one process
echoes them back, using the blocking MPI send and receive calls for all
operations. Half the time interval observed by the rank zero process for each
exchange is a measure of the latency for messages of that size, as previously