bytrace
Overview
bytrace is a tool for you to trace processes and analyze performance. It encapsulates and extends the kernel ftrace and supports event tracking in the user space. With bytrace, you can open a user-space or kernel-space label you want to view (run the bytrace -l command to query all the supported labels) and run the --trace_begin and -o filename (or --output filename) commands to capture traces and dump them to a specified file.
How to Develop
bytrace supports the following commands:
Table 1 Commands
| Option | Description |
|---|---|
| -h, --help | Views the help text for bytrace. |
| -b n, --buffer_size n | Sets the size of the buffer (KB) for storing and reading traces. The default buffer size is 2048 KB. |
| -t n, --time n | Sets the bytrace uptime in seconds, which depends on the time required for analysis. |
| --trace_clock clock | Sets the type of the clock for adding a timestamp to a trace, which can be boot (default), global, mono, uptime, or perf. |
| --trace_begin | Starts capturing traces. |
| --trace_dump | Dumps traces to a specified position (console where you run this command by default). |
| --trace_finish | Stops capturing traces and dumps traces to a specified position (console where you run this command by default). |
| -l, --list_categories | Lists the bytrace categories supported by the device. |
| --overwrite | Sets the action to take when the buffer is full. If this option is used, the latest traces are discarded; if this option is not used, the earliest traces are discarded (default). |
| -o filename, --output filename | Outputs traces to a specified file. |
| -z | Compresses a captured trace. |
Usage Example
The following are some examples of bytrace commands:
- Query supported labels.
bytrace -l
Alternatively, run the following command to query the supported bytrace categories:
bytrace --list_categories
- Capture traces whose label is ability, with the buffer size set to 4096 KB and bytrace uptime set to 10s.
bytrace -b 4096 -t 10 --overwrite ability > /data/mytrace.ftrace
- Set the clock type for traces to mono.
bytrace --trace_clock mono -b 4096 -t 10 --overwrite ability > /data/mytrace.ftrace
- Compress the captured trace.
bytrace -z -b 4096 -t 10 --overwrite ability > /data/mytrace.ftrace