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Creating a Hotspot Function Analysis Task

Function

The tool analyzes C/C++ program code, identifies performance bottlenecks, and provides details about the top 30 hotspot functions and call stacks. It also displays the function call relationship in flame graphs and provides the tuning path.

Prerequisites

  • No nodes are in the Offline state.

Procedure

  1. Click next to System Profiler.

    Choose General Analysis from the drop-down list. The page for creating a task is displayed.

  2. Set task parameters by referring to "Task Management" and Table 1.
    Create a hotspot function analysis task. See Figure 1.
    Figure 1 Creating a hotspot function analysis task
    Table 1 Parameters for creating a hotspot function analysis task

    Parameter

    Description

    Task Name

    Name of the task. The name must meet the following requirements:

    1. Contain only letters, digits, and underscores (_).
    2. Contain 1 to 64 characters.

    Select Nodes

    Select the nodes to be analyzed. If there is only one node, this node is selected by default. A maximum of 10 nodes can be selected at a time.

    Analysis Object

    Select System or Application.

    Mode

    Select Launch application or Attach to process.

    This parameter is mandatory when Analysis Object is set to Application.

    Application Path

    Enter the absolute path of the application to be analyzed. For example, to analyze the loop_test application stored in the /home/test directory, enter /home/test/loop_test.

    This parameter is mandatory when Analysis Object is set to Application and Mode is set to Launch application.

    NOTE:
    • By default, applications in the /opt/ or /home/ directory are analyzed. The administrator can click in the upper right corner on the home page and choose Tool Settings > System Profiler > System Settings, and enter application paths (separated by semicolons) in the Application Path text box. Only administrators can modify this parameter. Common users can only view this parameter.

      You are advised to set the application path to a path such as /home or /opt. Do not set the application path to a system directory such as /, /dev, /sys, or /boot. Otherwise, system exceptions may occur.

    • The OS running user (devkitworker1) of the System Profiler must have the read and execute permissions on the applications to be analyzed.
    • In the multi-node scenario, you can enable Configure Node Parameters to configure this parameter separately for each node.

    (Optional) Application Parameters

    Used for executing the application. Set this parameter based on the actual scenario.

    This parameter is available when Analysis Object is set to Application and Mode is set to Launch application.

    NOTE:

    In the multi-node scenario, you can enable Configure Node Parameters to configure this parameter separately for each node.

    (Optional) Application User

    Information about the OS user who runs the application. The application runs under the preset devkitworker1 user by default. If the application only runs under a specific user, enable the option, configure the corresponding user name and password, and then run the application.

    This parameter is available when Mode is set to Launch application. By default, this parameter is disabled.

    Name

    Name of the OS user who runs the application.

    This parameter is mandatory when Application User is enabled.

    Password

    User password.

    This parameter is mandatory when Application User is enabled.

    Process

    Enter a process name. The process name can be a regular expression.

    This parameter is mandatory when Analysis Object is set to Application and Mode is set to Attach to process.

    (Optional) PID

    Enter a maximum of 128 PIDs of the processes to be analyzed. Use commas (,) to separate the PIDs. PID and Process can be configured together.

    This parameter is available when Analysis Object is set to Application and Mode is set to Attach to process.

    NOTE:
    • If Attach to process is selected, the tool associates the ID of the process that runs an application to trace and collect the performance data of the application in real time. The OS running user devkitworker1 of the System Profiler must have the read permission on the application.
    • To query the PID, run the ps -ef | grep Program_name command.
    • You can enable Configure Node Parameters to configure this parameter separately for each node.

    Analysis Type

    Select Hotspot Function.

    Sampling Duration (s)

    Sampling duration, in seconds. The default value is 30. The value range is 1 to 1800.

    As the sampling duration increases, the collection processing may stop if the run directory space becomes insufficient. A maximum of 10 GB data is allowed. If the sampling duration is too long, a large number of resources and time will be consumed during collection and processing. Set this parameter properly.

    (Optional) Call Stack

    Enable this option to collect and display call stack data and flame graphs. If this option is disabled, only top 30 hotspot functions are collected. It is enabled by default.

    Sampling Delay (s)

    The sampling starts after the specified time. This parameter is used to ignore the program startup analysis, warm up the sampling program, and eliminate sampling delay caused by factors such as environment detection. The default value is 0. The value range is 0 to 900.

    You need to set this parameter in Advanced Configurations when Analysis Object is set to Application and Mode is set to Launch application.

    Sampling Frequency (Times/s)

    Number of samplings per second. The default value is 100. The value ranges from 1 to 500. You need to set this parameter in Advanced Configurations.

    (Optional) Sampling Range

    Sampling range. The default value is All. You can set this parameter in Advanced Configurations. The options are: The options are:

    • All: collects performance data of the application layer and OS kernel.
    • User Mode: collects performance data of the application layer.
    • Kernel Mode: collects performance data of the OS kernel.

    (Optional) CPU Cores to Be Sampled

    Enter the CPU core ID, which can be configured in Advanced Configurations.

    NOTE:
    • Set this parameter if you want to collect the performance data of an application on a CPU core. Enter one or more CPU core IDs here. The value range is 0 to the total number of CPU cores of the server minus 1. For example, if you enter 0,1,2,10 for a 16-core CPU, performance data of CPU cores 0, 1, 2, and 10 will be collected and analyzed.
    • You can enable Configure Node Parameters to configure this parameter separately for each node.

    C/C++ Source File Directory

    Enter the C/C++ source file project directory. This parameter can be set in Advanced Configurations when Analysis Object is set to Application.

    Task Execution

    The options are Execute now (default) and On a schedule. You need to set this parameter in Advanced Configurations.

    If On a schedule is selected, you need to set Sampling Mode, Sampling Time, and Sampling Date.

    For Periodical sampling mode, the task runs once a day in the sampling period. You need to set Sampling Time and Sampling Date.

    For One-Time sampling mode, the task takes effect only once. You need to set Sampling Date and Time.

    NOTE:
    • A user can create a maximum of 20 scheduled tasks.
    • You can click in the upper right corner of the page, choose Tool Settings > System Profiler, and click the Scheduled Tasks tab to view, edit, or delete (batch deletion supported) the created scheduled tasks.
    • The Restart button is unavailable for scheduled tasks.

    If there are a large number of program processes or a large amount of data to be analyzed, task timeout may occur. To prevent this problem, you can reduce the value of Collection Duration (s) or increase the value of Sampling Interval (ms).

  3. Click OK.

    You can click the icons next to the task name to perform the following operations:

    • : cancels an analysis task. After an analysis task is canceled, the collected information will be deleted.
    • : restarts an analysis task. You can modify task parameter settings and restart an analysis task. This button is available when a task is canceled or fails.
    • : deletes an analysis task. After a task is deleted, all data of this task will be deleted. Exercise caution when performing this operation.
    • : performs an analysis again. The analysis task is renamed and restarted.
    • : creates a task for comparing analysis results.
    • : modifies the task or report name. The report naming rule is the same as that of a task.
    • : creates a comparison analysis task. Differential flame graphs will be generated.