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Systems Performance Engineering
Performance engineering encompasses the techniques applied during a systems development life cycle to ensure the non-functional requirements for performance (such as throughput, latency, or memory usage) will be met. It may be alternatively referred to as systems performance engineering within systems engineering, and software performance engineering or application performance engineering within software engineering. As the connection between application success and business success continues to gain recognition, particularly in the mobile space, application performance engineering has taken on a preventive and perfective"Banking Industry Lessons Learned in Outsourcing Testing Services," Gartner. August 2, 2012. role within the software development life cycle. As such, the term is typically used to describe the processes, people and technologies required to effectively test non-functional requirements, ensure adherence to service levels and optimize application performance prior t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systems Development Life Cycle
In systems engineering, information systems and software engineering, the systems development life cycle (SDLC), also referred to as the application development life cycle, is a process for planning, creating, testing, and deploying an information system. The SDLC concept applies to a range of hardware and software configurations, as a system can be composed of hardware only, software only, or a combination of both. There are usually six stages in this cycle: requirement analysis, design, development and testing, implementation, documentation, and evaluation. Overview A systems development life cycle is composed of distinct work phases that are used by systems engineers and systems developers to deliver information systems. Like anything that is manufactured on an assembly line, an SDLC aims to produce high-quality systems that meet or exceed expectations, based on requirements, by delivering systems within scheduled time frames and cost estimates. Computer systems are complex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Profiler (computer Science)
In software engineering, profiling (program profiling, software profiling) is a form of dynamic program analysis that measures, for example, the space (memory) or time complexity of a program, the usage of particular instructions, or the frequency and duration of function calls. Most commonly, profiling information serves to aid program optimization, and more specifically, performance engineering. Profiling is achieved by instrumenting either the program source code or its binary executable form using a tool called a ''profiler'' (or ''code profiler''). Profilers may use a number of different techniques, such as event-based, statistical, instrumented, and simulation methods. Gathering program events Profilers use a wide variety of techniques to collect data, including hardware interrupts, code instrumentation, instruction set simulation, operating system hooks, and performance counters. Use of profilers The output of a profiler may be: * A statistical ''summary' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Web Performance
Web performance refers to the speed in which web pages are downloaded and displayed on the user's web browser. Web performance optimization (WPO), or website optimization is the field of knowledge about increasing web performance. Faster website download speeds have been shown to increase visitor retention and loyalty and user satisfaction, especially for users with slow internet connections and those on mobile devices. Web performance also leads to less data travelling across the web, which in turn lowers a website's power consumption and environmental impact. Some aspects which can affect the speed of page load include browser/server cache, image optimization, and encryption (for example SSL), which can affect the time it takes for pages to render. The performance of the web page can be improved through techniques such as multi-layered cache, light weight design of presentation layer components and asynchronous communication with server side components. History In the first decad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Testing
Software testing is the act of checking whether software satisfies expectations. Software testing can provide objective, independent information about the Quality (business), quality of software and the risk of its failure to a User (computing), user or sponsor. Software testing can determine the Correctness (computer science), correctness of software for specific Scenario (computing), scenarios but cannot determine correctness for all scenarios. It cannot find all software bug, bugs. Based on the criteria for measuring correctness from an test oracle, oracle, software testing employs principles and mechanisms that might recognize a problem. Examples of oracles include specifications, Design by Contract, contracts, comparable products, past versions of the same product, inferences about intended or expected purpose, user or customer expectations, relevant standards, and applicable laws. Software testing is often dynamic in nature; running the software to verify actual output ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Quality
In the context of software engineering, software quality refers to two related but distinct notions: * Software's functional quality reflects how well it complies with or conforms to a given design, based on functional requirements or specifications. That attribute can also be described as the fitness for the purpose of a piece of software or how it compares to competitors in the marketplace as a worthwhile product. It is the degree to which the correct software was produced. * Software structural quality refers to how it meets non-functional requirements that support the delivery of the functional requirements, such as robustness or maintainability. It has a lot more to do with the degree to which the software works as needed. Many aspects of structural quality can be evaluated only statically through the analysis of the software's inner structure, its source code (see Software metrics), at the unit level, and at the system level (sometimes referred to as end-to-end testin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scalability
Scalability is the property of a system to handle a growing amount of work. One definition for software systems specifies that this may be done by adding resources to the system. In an economic context, a scalable business model implies that a company can increase sales given increased resources. For example, a package delivery system is scalable because more packages can be delivered by adding more delivery vehicles. However, if all packages had to first pass through a single warehouse for sorting, the system would not be as scalable, because one warehouse can handle only a limited number of packages. In computing, scalability is a characteristic of computers, networks, algorithms, networking protocols, programs and applications. An example is a search engine, which must support increasing numbers of users, and the number of topics it indexes. Webscale is a computer architectural approach that brings the capabilities of large-scale cloud computing companies into enterprise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Performance
In software development, the programming language Java was historically considered slower than the fastest third-generation typed languages such as C and C++. In contrast to those languages, Java compiles by default to a Java Virtual Machine (JVM) with operations distinct from those of the actual computer hardware. Early JVM implementations were interpreters; they simulated the virtual operations one-by-one rather than translating them into machine code for direct hardware execution. Since the late 1990s, the execution speed of Java programs improved significantly via introduction of just-in-time compilation (JIT) (in 1997 for Java 1.1), the addition of language features supporting better code analysis, and optimizations in the JVM (such as HotSpot becoming the default for Sun's JVM in 2000). Sophisticated garbage collection strategies were also an area of improvement. Hardware execution of Java bytecode, such as that offered by ARM's Jazelle, was explored but not depl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trend Analysis
Trend analysis is the widespread practice of collecting information and attempting to spot a pattern. In some fields of study, the term has more formally defined meanings. Although trend analysis is often used to predict future events, it could be used to estimate uncertain events in the past, such as how many ancient kings probably ruled between two dates, based on data such as the average years which other known kings reigned. Project management In project management, trend analysis is a mathematical technique that uses historical results to predict future outcome. This is achieved by tracking variances in cost and schedule performance. In this context, it is a project management quality control tool. Statistics In statistics, trend analysis often refers to techniques for extracting an underlying pattern of behavior in a time series which would otherwise be partly or nearly completely hidden by noise. If the trend can be assumed to be linear, trend analysis can be undertaken wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Service Level Agreement
A service-level agreement (SLA) is an agreement between a service provider and a customer. Particular aspects of the service – quality, availability, responsibilities – are agreed between the service provider and the service user. The most common component of an SLA is that the services should be provided to the customer as agreed upon in the contract. As an example, Internet service providers and telcos will commonly include service level agreements within the terms of their contracts with customers to define the level(s) of service being sold in plain language terms. In this case, the SLA will typically have a technical definition of '' mean time between failures'' (MTBF), '' mean time to repair'' or '' mean time to recovery'' (MTTR); identifying which party is responsible for reporting faults or paying fees; responsibility for various data rates; throughput; jitter; or similar measurable details. Overview A service-level agreement is an agreement between two or m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capacity Planning
Capacity planning is the process of determining the production capacity needed by an organization to meet changing demands for its products. In the context of capacity planning, design capacity is the maximum amount of work that an organization or individual is capable of completing in a given period. Effective capacity is the maximum amount of work that an organization or individual is capable of completing in a given period due to constraints such as quality problems, delays, material handling, etc. The phrase is also used in business computing and information technology as a synonym for capacity management. IT capacity planning involves estimating the storage, computer hardware, software and connection infrastructure resources required over some future period of time. A common concern of enterprises is whether the required resources are in place to handle an increase in users or number of interactions. Capacity management is concerned about adding central processing units (CP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Performance Tuning
Performance tuning is the improvement of system Computer performance, performance. Typically in computer systems, the motivation for such activity is called a performance problem, which can be either real or anticipated. Most systems will respond to increased Load (computing), load with some degree of decreasing performance. A system's ability to accept higher load is called scalability, and modifying a system to handle a higher load is synonymous to performance tuning. Systematic tuning follows these steps: # Assess the problem and establish numeric values that categorize acceptable behavior. # Measure the performance of the system before modification. # Identify the part of the system that is critical for improving the performance. This is called the bottleneck (software), bottleneck. # Modify that part of the system to remove the bottleneck. # Measure the performance of the system after modification. # If the modification makes the performance better, adopt it. If the modificatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress Testing (software)
Stress testing is a software testing activity that determines the robustness of software by testing beyond the limits of normal operation. Stress testing is particularly important for "mission critical" software, but is used for all types of software. Stress tests commonly put a greater emphasis on robustness, availability, and error handling under a heavy load, than on what would be considered correct behavior under normal circumstances. A system stress test refers to tests that put a greater emphasis on Robustness (computer science), robustness, availability, and error handling under a heavy load, rather than on what would be considered correct behavior under normal circumstances. In particular, the goals of such tests may be to ensure the software does not crash (computing), crash in conditions of insufficient computational resources (such as Random access memory, memory or Disk storage, disk space), unusually high concurrency (computer science), concurrency, or denial of service ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
