性能测试相关概念及流程

本文整理来自pro Apache jmter web application和Wikipedia

在一定的负载条件下，评估系举桥统或应用的响应时间，吞吐量等相关指标

功能测试通过之后

对系统进行性能评估，并通过测试发现系统谨慧瓶颈，分析定位瓶颈发生的原因，协助开发修复性能问题，提高系统的处理能力。对比不同的系统，确认更好的系统。

主要指标： 响应时间、吞吐量、资源利用率。

The time taken by the application to respond to the user’s request is called the response time.Every application should strive to minimize the response time

应用程序响应用户请求所需的时间称之为--响应时间。响应时间越小越好

对于常见的B/S结构的响应时间，如下图：

从用户发起请求，到服务完全完成响应的时间。

用户感知时间，有点预加载的意思。即本来一个页面全部信息同时返回，现在改成优先加载一部分内容

服务器处理时间。服务器处理请求并响应的这段时间。与请求的复杂性、系统的硬件及系统服负载有关。

吞吐量：单位时间内处理的事务个数。通常由transactions/second 或 bandwidth (bytes/second)来衡量。吞吐量越大越好。

服务器资源利用率，不应该超过80%的利用率。利用率越低越好。

Scalability measures how well the system can expand its capacity when additional resources are added.Ideally the system capacity will increase linearly as additional resources are added. However, this is rarely achieved in practice. It’s a good measure to know the resources that would be needed so that the system can handle the projected future load.Vertical scalability is achieved by upgrading the hardware. For example, by adding more memory, disk,

a better CPU, or additional CPUs.Horizontal scalability is achieved by adding servers to the cluster. For example, by adding more web

servers and application servers to a webfarm/cluster.

主要有压力测试，负载测试，配置测试等

压力测试是应用程序处于超出负荷状态下长时间运行，以测试服务器的稳定性和性能表现。

A load test is a kind of performance test that’s performed at the specified load level. So ideally, we would like to perform load tests at varying load levels to note the behavior of the application.

在一定的负载条件下，测试应用程序的性能表现。通过不同的负载程正晌猛度（load levels）,观察应用程序的性能表现来得到最大的用户数，响应时间以及资源利用率等指标。

A peak load test is performed at the load that the application is expected to handle. For example, e-commerce web sites experience their peak traffic during Black Friday, Cyber Monday, and the Christmas holidays. So a peak load test in this case would test the application within the load specification but at the higher end.

Note stress tests test beyond the peak load.

In a soak test (also called an endurance test), the application is subjected to a specified load that is within the specified limit but for a long duration. It is performed for many hours at a time. This test determines if the application is properly reusing its resources.

This test will surface problems like the following:

Successful web applications experience massive and sometimes exponential growth. So it is wise to measure how the application scales. Scalability is defined as how well the application handles the increase in load while still meeting the desired performance criteria.

A scalability test would increase the resources and test whether or not the application is providing

a corresponding increase in capacity. Ideally, we expect linear scalability (i.e., doubling the hardware resources should result in double the application capacity).

A capacity test is a load test that establishes the maximum load that the application can handle while

meeting the desired performance criteria. The resulting metric is called the maximum capacity. It is used in scaling the application and to estimate costs for future growth.

A spike test is a load test where the application is subjected to brief periods of sudden increment in load, a small fraction beyond the maximum capacity. It is usually done to estimate the weakness/strength of an application. The application is expected to be robust and continue to meet the performance criteria during the spike. This metric is called the burst capacity.

In a performance smoke test, a few common and essential use-cases along with use-cases pertaining to the

code subject to change are together tested for performance. It is only when the smoke test succeeds that

the full suite of performance tests are conducted. If the smoke test fails, no further performance tests areconducted until the performance defect has been rectified.

Modern web application infrastructure is designed to be highly available and resilient to hardware and software failures. Ideally, the architecture should ensure that there is no single point of failure and that there are standby servers that can transparently take over without impacting the user experience.

In this test various equipment and software failures are simulated and relevant performance tests are

run to verify that the application is still meeting the performance criteria.

Rather than testing for performance from a load perspective, tests are created to determine the effects of configuration changes to the system's components on the system's performance and behaviour. A common example would be experimenting with different methods of load-balancing

《大学英语II》第01章在线测试

1、We used A at the same department.

A、to work B、to working C、working D、work

2、It is A for us to see the great changes in our hometown.

A、amazing B、amazed C、amazes D、to amaze

3、 B may cause lung cancer. B

A、Smoke B、Smoking C、Smokes D、Smoked

4、How about C with us to dinner today?

A、come B、. to come C、coming D、comes

5、If you keep C , you will succeed sooner or later.

A、to try B、tried C、trying D、tries

《大学英语II》第02章在线测试

1、By the time she is 50 years old, she A an inmate of the prison for over half of her life.

A、will have been B、will be C、would have been D、would be

2、It B for over a month and the downpour had damaged many houses.

A、rained heavily B、had been raining cats and dogs

C、has been raining heavily D、has rained cats and dogs

3、“What do you think of the boxing match last night?”“I really B think Jackson.”

A、don’t … has won B、didn’t … would win

C、didn’t … wins D、don’t … wins

4、Between 1897 and 1919, at least 29 motion pictures C .

A、had produced B、have been produced

C、had been produced D、would have produced

5、Our modern civilization must not be thought of as D in a short period of time.

A、being created B、having created C、creating D、having been created

《大学英语II》第03章在线测试

1、 C that silver is not widely used as a conductor?

A、Why is B、Is it why C、Why is it D、Why is that

2、Was it during the Second World War A he died?

A、that B、while C、in which D、then

3、I A swimming very much and I go swimming everyday.

A、did like B、do like C、does like D、can like

4、This headmaster was D I meant.

A、whom B、why C、which D、who

5、The two brothers are so nearly alike that I can’t tell C is .

A、what, what B、what, who C、who, who D、who, what

《大学英语II》第04章在线测试

1、So ＿＿D＿＿ in the darkness that he didnˊt dare to move an inch.

A、he was frightened B、was he frightened

C、frightened he was D、frightened was he

2、＿＿C＿， I will not buy it.

A、Much as do I like it B、As much I like it

C、Much as I like it D、As I like it much

3、Only after I read the text over again ＿＿B＿＿ its main idea.

A、that I knew B、did I know C、1 could know D、I did know

4、Little ＿＿D＿＿ when I took the trip where it would lead me.

A、have I known B、had I known C、do I know D、did I know

5、Not only ＿＿A＿＿ a promise, but also he kept it.

A、did he make B、he made C、does he make D、has he made

《大学英语II》第05章在线测试

1、He had just got out of the bus there was a fire in it. C

A、while B、till C、when D、as

2、People do not know the value of health they lose it. C

A、if B、when C、until D、while

3、In holidays, you can visit you are fond of. D

A、where B、which C、when D、wherever

4、＿＿＿＿＿ I know, he has failed English exam twice. A

A、So far as B、So long as C、According to D、What

5、He must have heard the bad news, he looks upset. B

A、because B、for C、when D、as

《大学英语II》第06章在线测试

1、The first place a tourist is taken to see in Zhengzhou is the Erqi Monument. A

A、that B、which C、what D、for

2、The effort to finish the project, he had expected, was a success. D

A、which B、like C、that D、as

3、The car drove recklessly, caused the accident. C

A、it B、that C、which D、who

4、He is the only one of the students who good at chess. B

A、do B、is C、does D、are

5、Anny, in house I spent my holiday, is an old friend of mine. D

A、his B、which C、whom D、whose

《大学英语II》第07章在线测试

1、1. ＿ he said at the meeting shocked everybody. A

A、What B、That C、The fact D、The matter

2、Mike didn’t understand ＿ made his wife so upset this morning. A

A、what B、why C、how D、which

3、The argument remained heated B there are necessary conditions of existence such as water on the Moon.

A、that B、whether C、if D、about which

4、The boy dived into the water and after B seemed to be a long time, he came up again.

A、that B、what C、where D、the place where

5、Mary wrote an article on A .

A、why B、what C、who D、that

《大学英语II》第08章在线测试 ADBCC

1、Many a student ＿＿＿＿＿＿ finished this assignment．

A、has B、have C、is seen D、sees

2、Physics ＿＿＿＿＿＿＿ my favorite subject.

A、be B、are C、am D、is

3、The rich＿＿＿＿＿＿ not always happy．

A、is B、are C、has D、have

4、Ten thousand dollars＿＿＿＿＿＿ more than I can afford．

A、has been B、have been C、is D、are

5、The number of people who own cars ＿＿＿＿＿＿＿ increasing.

A、has B、have C、is D、are

《大学英语II》第09章在线测试 CBBCB

1、Cleaning women in big cities usually get ＿＿＿＿＿＿ by the hour.

A、pay B、paying C、paid D、to pay

2、I ＿＿＿＿＿＿ to stay here if I can.

A、have been meaning B、mean C、am meaning D、have meant

3、In order to improve English, ＿＿＿＿＿＿.

A、Jane’s father bought her a lot of tapes B、Jane bought a lot of tapes for herself

C、a lot of tapes were bought by Jane D、a lot of tapes were bought for her by Jane’s father

4、Hundreds of jobs ＿＿＿＿＿＿ if the factory closes down.

A、lose B、will lose C、will be lost D、are lost

5、In the USA, he made a lot of friends ＿＿＿＿＿＿ English well so he could make himself ＿＿＿＿＿＿.

A、learn, understand B、to learn, understood C、learning, understood D、learn, understanding

《大学英语II》第10章在线测试 DDDAC

1、I wish I my uncle yesterday.

A、met B、have met C、would meet D、had met

2、Everything ＿＿＿＿＿＿ if Albert hadn’t called the fire brigade.

A、will be destroyed B、will have been destroyed

C、would be destroyed D、would have been destroyed

3、I was very busy yesterday, otherwise I to the meeting.

A、came B、would come C、had come D、would have come

4、If it rain next week，the farmers could still have a good harvest.

A、should B、could C、would D、might

5、He the job well，but he so careless.

A、hadnˊt done，had been B、could have done，was

C、could do，was D、had done，had been

---