<< Chapter < Page
  Software engineering     Page 8 / 15
Chapter >> Page >

Performance testing

Not all software systems have specifications on performance explicitly. But every system will have implicit performance requirements. The software should not take infinite time or infinite resource to execute. "Performance bugs" sometimes are used to refer to those design problems in software that cause the system performance to degrade.

Performance has always been a great concern and a driving force of computer evolution. Performance evaluation of a software system usually includes: resource usage, throughput, stimulus-response time and queue lengths detailing the average or maximum number of tasks waiting to be serviced by selected resources. Typical resources that need to be considered include network bandwidth requirements, CPU cycles, disk space, disk access operations, and memory usage. The goal of performance testing can be performance bottleneck identification, performance comparison and evaluation, etc. The typical method of doing performance testing is using a benchmark - a program, workload or trace designed to be representative of the typical system usage.

Security testing

Software quality, reliability and security are tightly coupled. Flaws in software can be exploited by intruders to open security holes. With the development of the Internet, software security problems are becoming even more severe.

Many critical software applications and services have integrated security measures against malicious attacks. The purpose of security testing of these systems include identifying and removing software flaws that may potentially lead to security violations, and validating the effectiveness of security measures. Simulated security attacks can be performed to find vulnerabilities.

Testing automation

Software testing can be very costly. Automation is a good way to cut down time and cost. Software testing tools and techniques usually suffer from a lack of generic applicability and scalability. The reason is straight-forward. In order to automate the process, we have to have some ways to generate oracles from the specification, and generate test cases to test the target software against the oracles to decide their correctness. Today we still don't have a full-scale system that has achieved this goal. In general, significant amount of human intervention is still needed in testing. The degree of automation remains at the automated test script level.

The problem is lessened in reliability testing and performance testing. In robustness testing, the simple specification and oracle: doesn't crash, doesn't hang suffices. Similar simple metrics can also be used in stress testing.

When to stop testing?

Testing is potentially endless. We can not test till all the defects are unearthed and removed - it is simply impossible. At some point, we have to stop testing and ship the software. The question is when.

Realistically, testing is a trade-off between budget, time and quality. It is driven by profit models. The pessimistic, and unfortunately most often used approach is to stop testing whenever some, or any of the allocated resources - time, budget, or test cases - are exhausted. The optimistic stopping rule is to stop testing when either reliability meets the requirement, or the benefit from continuing testing cannot justify the testing cost. This will usually require the use of reliability models to evaluate and predict reliability of the software under test. Each evaluation requires repeated running of the following cycle: failure data gathering - modeling - prediction. This method does not fit well for ultra-dependable systems, however, because the real field failure data will take too long to accumulate.

Questions & Answers

Text editor project in c++
Ayesha Reply
hi daddy
Sreenu
hello sir
Ranjith
are unmanned flying machines that are built and equipped with various kinds of software systems that allow them to see, hear, and act. Discuss some of the societal challenges of building such kinds of systems.
johni Reply
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful. Write a short report for your manager expl
johni
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful.
johni
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful.
johni
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful. Write a short report for your manager expl
johni
You have developed a prototype of a software system and your manager is very impressed by it. She proposes that it should be put into use as a production sys tem, with new features added as required. This avoids the expense of system dev immediately useful.
johni
what is cocomo ?
Surabhi Reply
?
StReeT
give me coding of these projects
Aman Reply
feasibility study&fact gathering techniques
Nachi Reply
write about software engineering
Mandala Reply
8.10.0.
BARBU
define iterative model. example of iterative model. advantages and disadvantages of iterative model. when to use iterative model
Okello Reply
What is DFD in Software engineering
Hamid
i try out in netbeans this code:public class Profile { private Profile(int w) { // line 1 System.out.println(w); } public final Profile() { // line 5 System.out.println(10); } public static void main(String args[]) { Profile obj = new Profile(50); } } It is the question 5, and the answer is 50
Jacqueline Reply
how to join conversation
Bablu
i need help....Discuss the factors that influence the choice of the software development methodology to use when implementing software projects?(20)
tatenda Reply
The success rate of software development projects can be increased by using a methodology that is adequate for the specific characteristics of those projects.  then the focus on RAD,XP,RUP.
Hemant
hemant hie...it is a presentation i am working on...can you help me wth the introduction....please a powerful one hahahahha
tatenda
yes
Hemant
Define and show all Dipthongs and vowels used in english phonetics
Okendro Reply
what is the software engineering
Axmed Reply
please
Jennifer
hhahhaha
martin
software engineering is a organized process of activities for development a use full software . it may consist of : 1:spcecification 2:design 3: implementation 4: evolution:
hamayun
Please how can I create an application?
Eric Reply
please how can I create an application
Nchor
How do we create a software
Florence Reply
give a more direct question
Louis Reply
what is semantics?
amjad
what r the computer codes
Kawuba Reply
machine code, source code , object code, and byte code etc
Hemant

Get the best Software engineering course in your pocket!





Source:  OpenStax, Software engineering. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10790/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Software engineering' conversation and receive update notifications?

Ask