Perceived performance

Performance is a typical hygiene factor. Nobody notices a highly performing system. But when a system is not performing well enough, people start complaining quickly. As an example, a 2006 research by Akamai found that 75% of the 1,058 people asked would not return to websites that took longer than four seconds to load. Five years earlier, in 2001, a similar research revealed that people were willing to wait eight seconds.    

The increase in bandwidth (in 2001 people mostly used modems to dial-in to the Internet), and the positive experience of very fast loading websites (like Google’s lightweight landing page) dropped this figure to four seconds and it would not surprise me that it will drop even more in the forthcoming years.

In general, the performance of a system can be defined as the amount of useful work that is accomplished by a system compared to the time and resources it used. 

Perceived performance refers to how quickly a software feature appears to perform its task. Most people understand that running a very complex report in a BI environment takes longer than let’s say opening an email. But while people have intrinsic expectations about performance, they are seldom expressed in hard figures.

In general people tend to overestimate their own patience. Most people value predictability in performance. When the performance of a system is fluctuating, they get a bad experience, even if the fluctuation is relatively rare.

For instance, even when one gets a bad response time of a system once a week, it will color the perception of the system for a long time. In the mind of the users the system is often slow.

It is therefore important to have a system with a predictable and consistent performance. It is always best to inform the user about how long something will take (when it is not instantaneously of course). When the user knows she has to wait for 40 seconds to get a task performed, and is informed about it (for instance using a progress bar), she accepts it more quickly. On the other hand when the system seems unresponsive without a reason, people get irritated very quickly. Increasing the real performance of a system is one way to increase the perceived performance.

But when real performance cannot be increased (for instance due to physical limitations) or the cost of improving the performance is very high, some techniques can be used to increase perceived performance. Two of those techniques are splash screens and progress bars.

Of course the amount of time an application takes to start up, or the time it takes for a file to download, is not made any faster by showing a splash screen or a progress bar. However, showing these screens satisfies a typical human need: splash screens and progress bars provide visual feedback to inform the users that the system is handling their request and is busy performing work for them.

Drawing and refreshing a progress bar while loading a file satisfies the user who is waiting, but steals time from the process that is actually loading the file. However, usually this is only a very small amount of time and the benefit of a satisfied user is much higher.


This entry was posted on Dinsdag 05 April 2011

Earlier articles

Infrastructure as code

My Book

DevOps for infrastructure

Infrastructure as a Service (IaaS)

(Hyper) Converged Infrastructure

Object storage

Software Defined Networking (SDN) and Network Function Virtualization (NFV)

Software Defined Storage (SDS)

What's the point of using Docker containers?

Identity and Access Management

Using user profiles to determine infrastructure load

Public wireless networks

Supercomputer architecture

Desktop virtualization

Stakeholder management

x86 platform architecture

Midrange systems architecture

Mainframe Architecture

Software Defined Data Center - SDDC

The Virtualization Model

What are concurrent users?

Performance and availability monitoring in levels

UX/UI has no business rules

Technical debt: a time related issue

Solution shaping workshops

Architecture life cycle

Project managers and architects

Using ArchiMate for describing infrastructures

Kruchten’s 4+1 views for solution architecture

The SEI stack of solution architecture frameworks

TOGAF and infrastructure architecture

The Zachman framework

An introduction to architecture frameworks

How to handle a Distributed Denial of Service (DDoS) attack

Architecture Principles

Views and viewpoints explained

Stakeholders and their concerns

Skills of a solution architect architect

Solution architects versus enterprise architects

Definition of IT Architecture

What is Big Data?

How to make your IT "Greener"

What is Cloud computing and IaaS?

Purchasing of IT infrastructure technologies and services

IDS/IPS systems

IP Protocol (IPv4) classes and subnets

Introduction to Bring Your Own Device (BYOD)

IT Infrastructure Architecture model

Fire prevention in the datacenter

Where to build your datacenter

Availability - Fall-back, hot site, warm site

Reliabilty of infrastructure components

Human factors in availability of systems

Business Continuity Management (BCM) and Disaster Recovery Plan (DRP)

Performance - Design for use

Performance concepts - Load balancing

Performance concepts - Scaling

Performance concept - Caching

Perceived performance

Ethical hacking

Computer crime

Introduction to Cryptography

Introduction to Risk management

The history of UNIX and Linux

The history of Microsoft Windows

Engelse woorden in het Nederlands

Infosecurity beurs 2010

The history of Storage

The history of Networking

The first computers

Cloud: waar staat mijn data?

Tips voor het behalen van uw ITAC / Open CA certificaat

Ervaringen met het bestuderen van TOGAF

De beveiliging van uw data in de cloud

Proof of concept

Een consistente back-up? Nergens voor nodig.

Measuring Enterprise Architecture Maturity

The Long Tail

Open group ITAC /Open CA Certification

Human factors in security

Google outage

SAS 70

De Mythe van de Man-Maand

TOGAF 9 - wat is veranderd?

DYA: Ontwikkelen Zonder architectuur

Landelijk Architectuur Congres LAC 2008

InfoSecurity beurs 2008

Spam is big business

Waarom IT projecten mislukken

Stroom en koeling

Laat beheerders meedraaien in projecten

De zeven eigenschappen van effectief leiderschap

Archimate

Een ontmoeting met John Zachman

Open CA (voorheen: ITAC) - IT Architect certification

Persoonlijk Informatie Eigendom

Webcast

Live computable webcast

Lezing Trends in IT Security

Hardeningscontrole en hacktesting

Kennismanagement

Information Lifecycle Management - Wat is ILM

LEAP: de trip naar Redmond

LEAP: De laatste Nederlandse masterclasses

Scada systemen

LEAP - Halverwege de Nederlandse masterclasses

Beveiliging van data - Het kasteel en de tank

Waarom je geen ICT architect moet worden

Non-functional requirements

Redenen om te backuppen

Log analyse - gebruik logging informatie

LEAP - Microsoft Lead Enterprise Architect Program

Archivering data - more than backup

Patterns in IT architectuur

Tot de dood ons scheidt

High Availability clusters

Hoe geef ik een goede presentatie

Lagen in ICT Beveiliging

Zachman architectuur model

High performance clusters en grids

Redenen om te kiezen voor Open Source software

Monitoring door systeembeheerders

Wat is VMS?

IT Architectuur certificeringen

Storage Area Network's (SAN's)

Systeembeheer documentatie

Wat zijn Rootkits

Virtualisatie van operating systems

Kenmerken van Open Source software

Linux certificering: RHCE en LPI

99,999% beschikbaarheid

Het infrastructuur model

Sjaak Laan


Recommended links

Genootschap voor Informatie Architecten
Ruth Malan
Informatiekundig bekeken
Gaudi site
Byelex
XR Magazine
Esther Barthel's site on virtualization


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The postings on this site are my opinions and do not necessarily represent CGI’s strategies, views or opinions.

 

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