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Creating an I/O Analysis Task

Function

By analyzing block storage devices, the tool obtains performance data such as the number of I/O operations, I/O data size, I/O queue depth, and I/O operation delay, and identifies specific I/O operations, processes, threads, call stacks, and I/O APIs in the application layer. Based on the I/O performance analysis, the tool provides tuning suggestions.

Prerequisites

  • No nodes are in the Offline state.
  • The system kernel supports ftrace collection.

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 an I/O analysis task. See Figure 1.
    Figure 1 Creating an I/O analysis task
    Table 1 Parameters for creating an I/O 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

    Set application parameters based on the actual scenario.

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

    NOTE:

    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 Name

    Enter a process name. The process name can be a regular expression. Enter either the process name or PID.

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

    PID

    Enter the IDs of the processes to be analyzed. A maximum of 128 PIDs can be entered. Use commas (,) to separate them. Enter either the process name or PID.

    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 I/O Performance.

    I/O Analysis Type

    Select Storage I/O.

    Sampling Duration (s)

    Sampling duration, in seconds. The default value is 30. The value range is 2 to 300.

    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 299.

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

    Statistical Period (s)

    Statistical period, in seconds. The value ranges from 1 (default) to 5. You need to set this parameter in Advanced Configurations.

    Size of the Collected File (MiB)

    Size of the file to be collected. The default value is 100. The value ranges from 10 to 2000. You need to set this parameter in Advanced Configurations.

    NOTE:

    You can control the file collection size to prevent the analysis from taking an overlong time. It takes about 50 minutes to collect and analyze 2000 MiB data.

    (Optional) Collect Call Stacks

    Indicates whether to collect data about call stacks. This parameter is disabled by default.

    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 Sampling Duration (s) or increase the value of Statistical Period (s).

  3. Click OK.

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

    • : cancels the analysis task. After an analysis task is canceled, the collected information will be deleted.
    • : restarts the 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 the analysis task. After a task is deleted, all data of this task will be deleted. Exercise caution when performing this operation.
    • : performs the analysis again. The analysis task is renamed and restarted.
    • : creates a task for comparing analysis results.
    • : changes the task or report name. The report naming rule is the same as that of a task.
Parent topic: I/O Analysis