hitrace

HiTrace provides APIs to implement call chain tracing throughout a service process. With this module, you can quickly obtain the run log specific to the call chain of a service process and locate faults across threads, processes, and devices.

Prerequisites

• The environment setup is complete.

• The devices are properly connected.

Command Description

Command	Description
-h	Displays help information.
-l	Displays the tag list.
--trace_begin	Starts capturing trace data.
--trace_finish	Stops capturing trace data.
--trace_dump	Dumps trace information.
-b N	Sets the buffer size (in KB) for trace data. The default buffer size is 2048 KB.
-t N	Sets the trace uptime in seconds, which depends on the time required for analysis. The default value is 5 seconds.
-o	Specifies the target file name (stdout by default).
-z	Compresses the trace data.
--trace_clock	Sets the type of the clock for adding a timestamp to a trace. The value can be boot (default), global, mono, uptime, or perf.
--trace_finish_nodump	Stops printing when trace capturing is stopped.
--start_bgsrv	Enables trace collection in snapshot mode.
--dump_bgsrv	Triggers trace output to a file in snapshot mode.
--stop_bgsrv	Disables trace collection in snapshot mode.

Description

The snapshot mode is a trace collection service with a fixed trace tag. By default, the trace data is not stored. You can run the --dump_bgsrv command to trigger trace dump at the current time. The trace file is in binary format and is generated in /data/log/hitrace by default. The file name format is trace-YYMMDDHHmmSS@[BOOT_TIME].sys. You can view the file using SmartPerf.

Examples

Run the following commands in the hdc shell:

1. Run the hitrace -l command to display the tag list.

   

2. Run the hitrace --trace_begin app command to start capturing trace data of the application.

   

3. Run the hitrace --trace_finish or hitrace --trace_finish -o /data/local/tmp/test.ftrace command to stop capturing trace data. The former prints the captured trace data in the command-line window, and the latter outputs the data to the specified file.

   

4. Run the hitrace -b 10240 -t 10 -o /data/local/tmp/test2.ftrace app ability command to capture trace data with the following settings:

   

   • Buffer size: 10240 KB
   • Trace uptime: 10s
   • Output path: /data/local/tmp/test1.htrace
   • Tags: app and ability

5. Run the hitrace --trace_dump or hitrace --trace_dump -o /data/local/tmp/test3.ftrace command to dump trace data. The former dumps trace data to the command-line window, and the latter dumps trace data to the specified file.

   

   You can also run the hitrace --trace_dump |grep *** command to dump trace data based on keywords.

6. Run the hitrace --start_bgsrv command to enable trace collection in snapshot mode.

   

7. Run the hitrace --dump_bgsrv command to enable trace collection in snapshot mode.

   By default, the trace information is stored in /data/log/hitrace/, which is in binary format. The file is named in the format of trace-YYMMDDHHmmSS@[BOOT_TIME].sys. You can view the file using SmartPerf.

   

8. Run the hitrace --stop_bgsrv command to disable trace collection in snapshot mode.