ib_write_bw
时间: 2025-06-23 15:24:39 浏览: 14
### InfiniBand Write Bandwidth Test Tool `ib_write_bw` Usage
The `ib_write_bw` utility, part of the perftest package[^1], serves as an essential tool for measuring the bandwidth performance of InfiniBand write operations between two nodes.
#### Command Syntax and Options
To use this tool effectively:
```bash
ib_write_bw <server> [<options>]
```
Common options include:
- `-a`: Use all available QPs (Queue Pairs).
- `-d <dev_name>`: Specify which HCA device to use.
- `-F`: Enable fast message mode.
- `-m <size>`: Set maximum transfer size in bytes.
- `-n <count>`: Define number of iterations.
- `-s <size>`: Start with specified buffer size.
- `-t <sec>`: Run time limit in seconds.
For detailed information on additional parameters, refer directly to the manual page or help option provided by the command itself.
#### Example Usage Scenario
A typical invocation might look like this when testing against a server named `infiniband-server`, specifying particular hardware characteristics:
```bash
ib_write_bw infiniband-server -d mlx5_0 -m 262144 -n 10000
```
This example sets up tests over device `mlx5_0`, uses messages sized at 262 KB, and runs through ten thousand iterations.
#### Performance Data Interpretation
Performance metrics generated from running these benchmarks typically report throughput values measured either in megabytes per second (MB/s) or gigabits per second (Gb/s). These figures provide insight into how efficiently data can be transferred across an InfiniBand network under varying conditions defined during setup. For precise interpretation of results obtained via `ib_write_bw`, consider factors such as underlying fabric configuration, concurrent traffic levels, and application-specific requirements that may influence observed outcomes.
--related questions--
1. What are some common troubleshooting steps if `ib_write_bw` reports lower-than-expected performance?
2. How does changing the queue pair count affect the output of `ib_write_bw`?
3. Can you explain what impact different InfiniBand transport modes have on write bandwidth measurements?
4. Is there any difference in using `ib_write_bw` versus other tools within the same suite for assessing RDMA capabilities?
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