bytrace Usage Guidelines
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:
- Run the following command to query supported labels:
Alternatively, you can run the following command:
bytrace --list_categories
- Run the following command to 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
- Run the following command to set the clock type for traces to mono:
bytrace --trace_clock mono -b 4096 -t 10 --overwrite ability > /data/mytrace.ftrace
- Run the following command to compress the captured trace:
bytrace -z -b 4096 -t 10 --overwrite ability > /data/mytrace.ftrace