Preface
1. How to understand performance testing?
Under high concurrent requests, check whether its response time and throughput rate meet the corresponding message requirements.
2. How do you understand the response time?
Response time refers to the sum of the period from the request to the response time. Simply put, the response time is the time required for a complete http request process.
3. How to distinguish between load testing and stress testing?
Load testing refers to multiple users making requests to the system at the same time until the performance indicators of the system exceed expectations or a certain program reaches a saturated state, thereby finding the processing limit of the system; its focus is on the number of concurrent users at the same time
The stress test refers to when the performance indicators of the system are in a saturated state, by making continuous requests to the system, checking whether the protocol status code returned after the request is 200ok, and whether there is an error message returned, so as to judge the operation of the system. stability
4. What are the commonly used performance testing software?
The performance testing software I commonly use is mainly JMeter and Locust; jmeter is used for regular testing, and locust is used for stability testing.
5. How does jmeter do performance testing?
First create a thread group, create an http request under the thread group, fill in the request parameters and assertions, and add performance testing plug-ins such as aggregate reports, response time graphs, and perfmon under the thread group, add the number of observation results, and then add Fill in the thread properties in the group and finally click Run
6. What data does the thread attribute in jmeter have?
Number of threads, Ramp-Up time, number of loops, scheduler, duration, startup delay
7. What data is included in the jmeter aggregation report?
Sampler name, sampler running test, average response time of a single request, 50%, 90%, 95%, 99% response time, maximum and minimum response time, throughput, error rate
8. How to monitor the CPU and memory of the server in jmeter?
We monitor by adding the perfmon plug-in and starting the download of severagent.
First, we install the perfmon plug-in, then download severagent and place it in the same directory as jmeter. After starting severagent, open jmeter, add the perfmon plug-in, and finally select cpu and memory in perfmon.
9. What is your understanding of the performance testing process?
First of all, we need to sort out the test process, clarify the test goals, prepare the required equipment, arrange personnel, and formulate a test plan. Then we start the design and development, execution and management of the test, and collect data. Finally, we will analyze the collected data. Analyze data, draw test conclusions, and write performance test reports
10. What should you do if the test results do not meet the expected goals?
At this time, we will first collect performance test data, then contact development, analyze the data to find the cause of the problem, and then optimize and stress test again until the results reach the expected results.
11. What are the important indicators of performance testing?
Response time: the time from the client sending a request to the server responding.
Throughput: the data transmission speed.
Number of concurrent users: the number of users sending requests to the server at the same time.
TPS/QPS: TPS is the transaction processing rate per second; QPS is Query rate per second
IOPS: Number of input/output operations per second
For Linux servers, we also pay attention to its CPU and memory
12. Tell us the relationship between the number of threads in the thread attribute and ramp_up time?
Number of threads/number of concurrencies per second = ramp_up time
13. How to do performance testing?
First, check with relevant personnel to see if performance testing is required for this iteration. If necessary, list the test scenarios and test purposes, and then review with relevant personnel. After passing the review, develop a test plan and arrange relevant personnel and equipment. Conduct performance testing;
During the process, collect performance test data. After the test is completed, analyze the obtained data to see if it meets expectations. If not, contact the development team to analyze and find out the reasons together, develop and optimize, and then stress test after optimization until it meets expectations;
Final programming performance test report;
14. If there is a memory leak in sending, how is it checked?
I will check the log file to see if there is out of memory in the log.
For example, the file upload function now needs to upload a file of 1 G size, but the system setting happens to allow the maximum upload file size to be 1 G.
Then while uploading, I also monitor the log to see if the ouf of memory keyword appears. If so, package the keyword context or take a screenshot and send it to the developer.
15. How to troubleshoot if the request takes a long time?
I check whether the timeout keyword appears in the log.
Or contact the development, please develop an output to add a response time, and then find the response time by checking the log. If it exceeds 5 seconds, it is a timeout.
16. If the performance test results are not satisfactory, what will you do?
First, I will collect performance test data, then contact the development, work with the development to find and discover problems, and then optimize.
After optimization, perform stress testing until expected goals are achieved.
17. How to use the jmeter monitoring tool?
The jmeter monitoring tool is used to monitor the CPU and memory resources of the Java program itself.
First, we first find the bin directory in the jdk directory in the java file, go to the jvisualvm application and open it, then double-click jmeter.jar, and finally click monitor, and you will see the cpu and memory data of java.
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