HiTraceMeter provides APIs for system performance tracing. You can call the APIs provided by HiTraceMeter module in your own service logic to effectively track service processes and check the system performance.
## Available APIs
The performance tracing APIs are provided by the **hiTraceMeter** module. For details, see [API Reference](../reference/apis/js-apis-hitracemeter.md).
The performance tracing APIs are provided by the **hiTraceMeter** module. For details, see [API Reference](../reference/apis/js-apis-hitracemeter.md).
[Description] The HDF places the same type of devices in the same host. You can develop and deploy the driver functionalities of the host by layer, so that one driver has multiple nodes. The following figure shows the HDF driver model.
Place devices of the same type in the same host. When adding a device, check whether the host of the same type already exists. If such a host already exists, configure the device in the host. Do not configure the same host again. A device belongs to only one driver. Therefore, do not configure the same device in different hosts.
# Use Case<a name="EN-US_TOPIC_0000001055686082"></a>
- For details about the development board, compilation, burning, and image running, see [Hi3518 Development Board](../quick-start/quickstart-lite-introduction-hi3518.md#section14815247616). A compilation result file of sample code is stored in **out/ipcamera\_hi3518ev300/dev\_tools/bin/camera\_sample**. You can copy the file to a TF card, or modify the compilation script of **camera\_sample** to copy the result to **rootfs.img**.
- For details about the development board, compilation, burning, and image running, see [Hi3518 Development Board](../quick-start/quickstart-lite-overview.md). A compilation result file of sample code is stored in **out/ipcamera\_hi3518ev300/dev\_tools/bin/camera\_sample**. You can copy the file to a TF card, or modify the compilation script of **camera\_sample** to copy the result to **rootfs.img**.
Modify **output\_dir** in **applications/sample/camera/media/BUILD.gn**.
For details about the compilation and burning processes, see [Building Source Code](../quick-start/quickstart-lite-steps-hi3861-connection.md#section191121332125319) and [Burning Images](../quick-start/quickstart-lite-steps-hi3861-connection.md#section3288165814218) in the _Getting Started with Hi3861_.
For details about the compilation and burning processes, see [Building](../quick-start/quickstart-lite-steps-hi3861-building.md) and [Burning](../quick-start/quickstart-lite-steps-hi3861-burn.md) in the _Getting Started with Hi3861_.
After the preceding two steps are complete, press the **RST** button to reset the module. If the LED blinks periodically as expected, the verification is passed.