Performance test Adjustment basis 1.1 performance test Adjustment basisPerformance adjustments are modifications to system software or hardware to improve system performance. Performance adjustment is not the responsibility of the tester. The main task of the Performance Testing Engineer is to identify and locate performance problems. Performance testing engineers, DBAs, system administrators, and developers usually work together to solve problems found during performance testing. However, it is necessary for testers to understand the adjustment knowledge. In performance testing, we often mention performance tuning or system tuning. In fact, "performance tuning" or "system tuning" is only part of performance tuning. For example, some parts may be "not optimal" to make some parts "better", so this book uses the "performance adjustment" statement. This section describes the basic knowledge of performance adjustment. Performance adjustment should be conducted in a certain order, including the following five steps:
1,
Confirm the problemFirst, determine whether the system has problems based on the test results, focusing on identifying system bottlenecks. If the problem exists, determine the problem and locate the problem correctly. Identify system problems from the following aspects: l application code: Generally, many program performance problems are "written. Therefore, for the module that finds the bottleneck, check the code first. l Database Configuration: The Database Configuration often causes the whole system to run slowly, for some large databases such as Oracle, DBA must make correct parameter adjustments before production. l Operating System Configuration: unreasonable operating system configuration may also cause system bottlenecks. l hardware settings: disk speed, memory size, and so on are prone to bottlenecks, so these are also the focus of analysis; l Network: excessive network load will lead to network conflicts and network latency. At the same time, we need to investigate the usage of the system. For example, does l hear complaints from many users? L is the response time of some operations getting longer and longer with the use time? L is the CPU usage low while the I/O usage High? L is the performance stable during use? System performance problems are not obvious. You need to find them carefully before you can locate them correctly.
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Identify the causeAfter you confirm that the system has a problem, you must analyze it carefully to determine the cause of the problem. The reason for determination depends largely on the team's experience and technical capabilities. The knowledge involved includes many aspects such as operating systems, databases, networks, and program development. As with determining performance issues, identifying causes still requires extensive information collection. The following analysis is usually performed: what is the impact of the L problem: response time, throughput, or other problems? L is there a problem with most users or a few users? If there are a few users, what are the differences between these users and the operations of other users? L is the result of system resource monitoring normal: Has the CPU usage reached its limit? What is the I/O condition? L is the problem concentrated in a certain type of module? L is there a problem with the client or server? L is the system hardware properly configured? L does the actual load exceed the system load capacity? L is the system not optimized? Through these analyses and the specific performance of the system, you can have a deeper understanding of the System Bottleneck and analyze the real causes.
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Determine adjustment targets and SolutionsAfter analyzing the cause of the problem, the tester and System Adjustment personnel should first determine the adjustment objectives and then design a solution. The main function of determining the adjustment target is to determine when to stop the adjustment system. Otherwise, the work will never end. Each system has different characteristics, so the adjustment targets may be different. For example, the following are System Adjustment goals: l improve system throughput; l shorten response time; l better support for concurrency; the main basis for designing solutions is these adjustment goals. With a clear plan and objectives, you can proceed with the subsequent work.
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Test SolutionAfter implementing the solution, we need to test the solution. You can use previous test cases to test whether the system has solved the performance problem. Test solutions should be carried out in a simulated environment as far as possible, because they may cause damages in the production environment unless the test risks are fully estimated and a remedy is prepared.
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Analyze adjustment resultsThe last step of performance adjustment is to analyze the adjustment results. If the problem is not solved, repeat the previous work. In the process of testing the system adjustment scheme, you should analyze the work you do frequently. If the problem cannot be accurately located or the adjustment scheme is incorrect, the expected goal may not be reached. These errors should be discovered as soon as possible so that the work can return to the correct track earlier. When analyzing the results, consider the following questions: does the system adjustment meet or exceed the predefined objectives? L is the overall performance of the system improved, or does it sacrifice some performance to solve the problem? L can the adjustment be completed?
