@ohos.hiTraceMeter (Performance Tracing)

The hiTraceMeter module provides the functions of tracing service processes and monitoring the system performance. It provides the data needed for hiTraceMeter to carry out performance analysis. For details about the development process, see Development of Performance Tracing.

NOTE

The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import hiTraceMeter from '@ohos.hiTraceMeter';

hiTraceMeter.startTrace

startTrace(name: string, taskId: number): void

Marks the start of a trace task.

If multiple trace tasks with the same name need to be performed at the same time or a trace task needs to be performed multiple times concurrently, different task IDs must be specified in OH_HiTrace_StartTrace.

If the trace tasks with the same name are not performed at the same time, the same taskId can be used. For a specific example, refer to an example in hiTraceMeter.finishTrace.

System capability: SystemCapability.HiviewDFX.HiTrace

Parameters

Example

hiTraceMeter.startTrace("myTestFunc", 1);

hiTraceMeter.finishTrace

finishTrace(name: string, taskId: number): void

Stops a trace task.

To stop a trace task, the values of name and task ID in finishTrace must be the same as those in startTrace.

System capability: SystemCapability.HiviewDFX.HiTrace

Parameters

Example

hiTraceMeter.finishTrace("myTestFunc", 1);

// Start trace tasks with the same name concurrently.
hiTraceMeter.startTrace("myTestFunc", 1);
// Service flow...
hiTraceMeter.startTrace("myTestFunc", 2);  // Start the second trace task with the same name while the first task is still running. The tasks are running concurrently and therefore their taskId must be different.
// Service flow...
hiTraceMeter.finishTrace("myTestFunc", 1);
// Service flow...
hiTraceMeter.finishTrace("myTestFunc", 2);

// Start trace tasks with the same name in serial mode.
hiTraceMeter.startTrace("myTestFunc", 1);
// Service flow...
hiTraceMeter.finishTrace("myTestFunc", 1);  // End the first trace task.
// Service flow...
hiTraceMeter.startTrace("myTestFunc", 1);   // Start the second trace task with the same name in serial mode.
// Service flow...
hiTraceMeter.finishTrace("myTestFunc", 1);

hiTraceMeter.traceByValue

traceByValue(name: string, count: number): void

Marks the value changes of a numeric variable in a trace task.

System capability: SystemCapability.HiviewDFX.HiTrace

Parameters

Example

let traceCount = 3;
hiTraceMeter.traceByValue("myTestCount", traceCount);
traceCount = 4;
hiTraceMeter.traceByValue("myTestCount", traceCount);
// Service flow...