Computer performance: Difference between revisions

Revision as of 11:10, 23 April 2024

Revision as of 13:10, 28 April 2024

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Computers run sets of instructions called a process. In operating systems, the execution of the process can be postponed if other processes are also executing. In addition, the operating system can schedule when to perform the action that the process is commanding. For example, suppose a process commands that a computer card's voltage output be set high-low-high-low and so on at a rate of 1000 Hz. The operating system may choose to adjust the scheduling of each transition (high-low or low-high) based on an internal clock. The latency is the delay between the process instruction commanding the transition and the hardware actually transitioning the voltage from high to low or low to high.

System designers building [[real-time computing]] systems want to guarantee worst-case response. That is easier to do when the CPU has low [[interrupt latency]] and when it has a deterministic response.

=== Bandwidth ===

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In communication networks, throughput is essentially synonymous to digital bandwidth consumption. In [[wireless network]]s or [[cellular communication networks]], the [[system spectral efficiency]] in bit/s/Hz/area unit, bit/s/Hz/site or bit/s/Hz/cell, is the maximum system throughput (aggregate throughput) divided by the analog bandwidth and some measure of the system coverage area.

In integrated circuits, often a block in a [[data flow diagram]] has a single input and a single output, and operateoperates on discrete packets of information. Examples of such blocks are [[Fast Fourier transform|FFT]] modules or [[binary multiplier]]s. Because the units of throughput are the reciprocal of the unit for [[propagation delay]], which is 'seconds per message' or 'seconds per output', throughput can be used to relate a computational device performing a dedicated function such as an [[ASIC]] or [[embedded processor]] to a communications channel, simplifying system analysis.

=== Scalability ===

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Perceived performance, in computer engineering, refers to how quickly a software feature appears to perform its task. The concept applies mainly to [[User acceptance test|user acceptance]] aspects.

The amount of time an application takes to start up, or a file to download, is not made faster by showing a startup screen (see Splash screen) or a file progress dialog box. However, it satisfies some human needs: it appears faster to the user as well as providingprovides a visual cue to let them know the system is handling their request.

In most cases, increasing real performance increases perceived performance, but when real performance cannot be increased due to physical limitations, techniques can be used to increase perceived performance.