Xiao Chief will tell you about confusing terms in performance testing today. If you have any questions, not limited to performance testing, you can leave a message to Xiao Chief in the WeChat official account~
1. Load testing and stress testing
Stress testing obtains the maximum service level test that the system can provide by determining the bottleneck or unacceptable performance point of a system .
In layman's terms, it is to test the maximum performance of the system, such as supporting the maximum number of concurrency.
Load testing is to determine the performance of the system under various workloads. The goal is to test how the corresponding input items of the system components, such as throughput, response time, CPU load, memory usage, etc., determine the performance of the system when the load gradually increases . Such as stability and responsiveness etc.
In layman's terms, it is the usage of various resources of the system under a specific load (such as the number of concurrency is 200), as well as the stability and response time changes of the tested application, and analyze whether there is a performance bottleneck.
Load testing usually describes a specific type of stress testing.
2. Fatigue strength test and stability test
Stability tests the length of period over which the application under test continues to function correctly .
In layman's terms, it refers to how long the application under test can continue to run without errors when it is used normally by the user.
The fatigue strength test usually uses the maximum number of concurrent users that can be supported by the tested application under stable operation, and continues to execute the business for a period of time (at least 24 hours), and determines the maximum workload intensity of the system through comprehensive analysis of transaction execution indicators and resource monitoring indicators performance process. It reflects the stability of the tested application from the side ( the stability is based on the assumption that the tested application can handle business correctly for a long time under high-intensity operation, so the system should also be able to correctly handle the business for a long time under normal use. processing business).
In layman's terms, it is to use the maximum number of concurrency supported by the tested application to simulate running the business for a long time, and analyze the stability of the system through resources and performance indicators. Because the stability test takes a lot of time (such as last month, last year), in most cases, the fatigue strength test is used instead of the stability test.
3. Memory overflow and memory leak
Out of memory The program requires more memory than the system can allocate .
In layman's terms, there is not enough memory. Usually the system will report an error similar to out of memory.
A memory leak means that after the program applies for memory, it cannot release the requested memory space . If the memory cannot be released, this memory cannot be used again. We say that this memory leaks.
In layman's terms, it means that the program does not release the memory in time after using it, resulting in waste of memory, which eventually leads to slow running of the program and system crash.
4. (relative) concurrency and (absolute) concurrency
(Relative) Concurrency refers to the number of operations on the function at the same time for a function (business, or server interaction, etc.) .
(Absolute) Concurrency for a function refers to the number of operations on that function over a period of time .
5. (relative) number of concurrent users and (absolute) number of concurrent users
(Absolute) Concurrent Users The number of online users interacting with the server at the same time .
(Relative) number of concurrent users The number of online users who have interacted with the server within a period of time (usually 1s).
6. The number of online users and the number of concurrent online users
For a website, when a user enters the website, he starts to perform various operations on the website, including browsing web pages, retrieving content, submitting forms, etc. Users in this process are called online users . The number of online users on the website within a period of time is called the number of online users ; while the number of online users on the website at the same time is called the number of concurrent online users .
7. Processes and threads
A process is an operation of a program with independent functions on a certain data set.
Thread A thread refers to a single sequential flow of control within a process .
The introduction of threads in the operating system is to reduce the time and space overhead of concurrent execution of programs, making development more detailed and concurrency better. A process can have many threads, and each thread performs different tasks in parallel. A process is a unit of resource allocation, while a thread is a unit of processor scheduling .
8. HPS and TPS
The number of clicks per second (or interaction with the server) of HPS refers to the sum of clicks (or the sum of the number of server interactions) by the user on the link of the Web page, the submit button, etc. within one second.
TPS is the number of transactions or transactions that the system can handle per second. It is an important indicator to measure the processing power of the system. A transaction operation, which can consist of multiple hits (or multiple server interactions).
Usually HPS is directly proportional to TPS.
9. Uplink bandwidth and downlink bandwidth
Uplink bandwidth refers to the bandwidth available for uploading resources.
Downlink bandwidth refers to the bandwidth available for downloading resources.
Practical case
Optical theory is useless, you have to learn to follow along, and you have to do it yourself, so that you can apply what you have learned to practice. At this time, you can learn from some actual combat cases.
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