Viewing System Configuration Analysis Results

Prerequisites

A tuning analysis task has been created and completed.

Procedure

1. In the Tuning Assistant area, click on the left of the target analysis task to expand the node list.
2. Click the name of the target node to view the analysis results.

   The analysis result page is displayed, which involves four parts: System Configuration, Hotspot Functions, System Performance, and Process/Thread Performance. By default, the system configuration analysis result is displayed. Click a node on the analysis result page and you will see the details page displayed on the right. You can also click to hide the details page.

   Figure 1 Analysis result page
   
3. (Optional) Select a service type and suggestion type.
   • Select a service types as required. The options are CPU-intensive, Network I/O-intensive, and Storage I/O-intensive. You can select one or more service types. By default, all the three options are selected.
     Figure 2 Selecting service types
     
   • Select a suggestion type based on the actual situation. You can adjust the topology tree by selecting Tuning path–based suggestions or Threshold-filtered suggestions.
     Figure 3 Selecting a suggestion type
     
4. Set tuning parameters based on the system configuration conditions.
   1. You can adjust the system configuration parameters on the right based on the system configuration.
      Figure 4 System configuration analysis result
      
      Table 1 describes System Config parameters.

      Table 1 System Config parameters

      Metric	Description
      dirty_expire_centiseconds	Specifies how long dirty data stays in the cache before being written into drives. If service data is written continuously, set this parameter to a smaller value to prevent burst I/O waiting caused by centralized I/Os.
      dirty_background_ratio	Specifies the maximum percentage of pages to the total memory before the dirty pages are written to drives by the pdflush process (based on memfree + cached – Mapped). Increasing the value of this parameter will allocate more memory for the write cache, thereby improving the drive write performance. However, for write-intensive services, set this parameter to a smaller value to prevent data from being stacked and causing performance bottlenecks. You can identify the bottleneck by observing the time fluctuation range of await and based on service characteristics.
      dirty_ratio	Specifies the maximum ratio of dirty pages to the total memory. If the ratio exceeds the value, the system does not flush dirty pages and the file read and write operations change to the synchronous mode. In the synchronous mode, the block time of the file read and write operations of the application is prolonged, which slows down the system. For write-intensive services, you can increase the value of this parameter to prevent the drive from entering the synchronous write state too early.
      dirty_expire_centisecs	Specifies the interval of the pdflush process for refreshing the dirty data of the kernel, in centiseconds. The default value is 500 (5 seconds). If the system writes data continuously, decrease the value of this parameter. In this way, intensive write operations can be split into multiple write operations. If the system performs intensive write operations in a short period of time and the data volume is not large (dozens of MB each time) and the memory is sufficient, increase the value of this parameter.
      Memory Free (%)	Controls the memory usage. If the memory usage is too high, the server performance deteriorates. In this case, you need to increase the percentage of free memory to ensure the normal running of the server. If the memory usage is low, decrease the value of swappiness to use the physical memory and reduce the usage of the swap partition. This prevents system performance from being affected by increased I/O operations.
      swappiness	swappiness is a Linux kernel attribute that sets the balance between swapping pages from the physical memory to the swap space and removing pages from the page cache. It basically defines the frequency at which the system uses the swap space.

      • Click Apply and make the modified configuration parameters take effect.
      • Click Reset to restore the default parameter configurations.
   2. View the tuning suggestion topology tree on the analysis result page. Click and to select the corresponding tuning suggestions based on the configuration conditions.
      Figure 5 Tuning suggestions
      
   3. View the Relevant Configurations, Indicator Description, Optimization Suggestion, and Optimization Guide on the right. Click to adopt the tuning suggestion, or to cancel the adoption of the tuning suggestion.
      Figure 6 Tuning suggestion page
      
   4. The adopted tuning suggestions are saved in the associated report. Click associated report in the lower right corner of the page to access the associated report page.

      All adopted tuning suggestions are displayed on the associated report page. You can click the task name to view the details. Click Valid or Invalid in the lower left corner to report whether the tuning suggestion meets the expectation.

      Figure 7 Associated report
      
5. Click on the right of system configuration analysis result tab page to view system configuration data.

   The system configuration details include the CPU, memory, storage, network, and OS configuration information. By default, the CPU tab page is displayed.

   Figure 8 Viewing system configuration data