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- Outdated ipath_ether Configuration Setup Generates Error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
B–Benchmark Programs
Benchmark 4: Measuring MPI Latency in Host Rings
IB6054601-00 H B-5
A
Searching for N/2 bandwidth. Maximum Bandwidth of 1958.400649
MB/s...
Found N/2 bandwidth of 992.943275 MB/s at size 153 bytes
This microbenchmark is available and can be downloaded from the QLogic web site:
http://www.qlogic.com
Benchmark 4: Measuring MPI Latency in Host
Rings
The program mpi_latency measures latency in a ring of hosts. Its syntax is
different from Benchmark 1 in that it takes command line arguments that let you
specify the message size and the number of messages over which to average the
results. For example, with a hosts file listing four or more nodes, the command:
$ mpirun -np 4 -ppn 1 -m mpihosts mpi_latency 100 0
might produce output like this:
0 1.760125
This output indicates that it took an average of 1.76 microseconds per hop to send
a zero-length message from the first host, to the second, to the third, to the fourth,
and then receive replies back in the other direction.