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- Outdated ipath_ether Configuration Setup Generates Error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
E–Write Combining
MTRR Mapping and Write Combining
IB6054601-00 H E-3
A
For systems with very large amounts of memory (32GB or more), it may also be
necessary to adjust the BIOS setting for the PCI hole granularity to 2GB. This
setting allows the memory to be mapped with fewer MTRRs, so that there will be
one or more unused MTRRs for the InfiniPath driver.
Some BIOS’ do not have the MTRR mapping option. It may have a different
name, depending on the chipset, vendor, BIOS, or other factors. For example, it is
sometimes referred to as 32 bit memory hole. This setting must be enabled.
If there is no setting for MTRR mapping or 32 bit memory hole, and you have
problems with degraded performance, contact your system or motherboard
vendor and ask how to enable write combining.
Use the ipath_mtrr Script to Fix MTRR Issues
QLogic also provides a script, ipath_mtrr, which sets the MTRR registers,
enabling maximum performance from the InfiniPath driver. This Python script is
available as a part of the InfiniPath software download, and is contained in the
infinipath* RPM. It is installed in /bin.
To diagnose the machine, run it with no arguments (as a root user):
# ipath_mtrr
The test results will list any problems, if they exist, and provide suggestions on
what to do.
To fix the MTRR registers, use:
# ipath_mtrr -w
Restart the driver after fixing the registers.
This script needs to be run after each system reboot. It can be set to run
automatically upon restart by adding this line in
/etc/sysconfig/infinipath
:
IPATH_MTRR_ACTIVE=1
See the ipath_mtrr(8) man page for more information on other options.