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<concept id="GUID-B77702FA-7385-51A0-986F-7667669CBDB2" xml:lang="en"><title>Guide to Optimising Performance</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>This document highlights areas to investigate as part of a system-wide

performance optimization process. </p>

<li id="GUID-32A6D5A9-4A2C-5EC0-B602-98C0B14A9487"><p>Performance

cannot be easily or usefully assessed until a device or system nears

completion. </p> </li>

<li id="GUID-572885AD-64E4-5963-AA44-7883239E33AA"><p>Performance

is often affected by interactions between components. </p> </li>

<li id="GUID-BF3A5F0F-10A1-5E44-8DA0-0A1089705B85"><p>Performance

is hardware related. </p> </li>

<li id="GUID-2363FD02-FD50-5837-A719-E976925C2F29"><p>Optimizations

can result in less easily maintained code. </p> </li>

<li id="GUID-6016203A-D493-5829-8A33-BB28DD21DDC3"><p>A few worthwhile

optimizations are much more efficient than many which have little

impact. </p> </li>

</ul> <p>This does not mean that improving or optimizing performance

should only be considered as a single activity to be performed towards

the end of a development project. Good practise and forward thinking

in all aspects from the outset are the most important contributors

to producing high-performance products. </p> <p>The Symbian Developer

Library is full of advice on how to write fast and efficient code

and how to configure your software and hardware for optimized performance. </p> </section>

<li id="GUID-62821E16-8F93-5C56-ADD7-B1D1ACA08AFB"><p>Increased execution

speed. Applications and processes perform or appear to perform tasks

in less time. </p> </li>

<li id="GUID-DEB5147F-3932-56F4-8E46-435A2A059B38"><p>Reduced start

up time. Devices are ready for use more quickly after being switched

on. </p> <p><xref href="GUID-AF30D941-BFD8-5260-9588-C5DA6983F558.dita">System Starter</xref>  </p> </li>

<li id="GUID-83720AE2-A308-59ED-8C20-FC7981486D4C"><p>Efficient ROM

and RAM use. ROM and RAM cost money. </p> <p><xref href="GUID-EFC99FD5-4EC2-5B9E-AE03-FE66D1ABF8A8.dita">Optimising Compressed

ROMs</xref>  </p> </li>

<li id="GUID-4554E6D0-76D7-589F-924A-9724074F8A0F"><p>Reduced power

consumption. </p> </li>

</ul> </section>

components support various build-time configuration parameters. These

include settings in configuration and initialization files, macro

definitions and patchable constant values. </p> <p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita">Adjustable Performance

Configuration</xref>  </p> <p><xref href="GUID-B526BA3A-14E4-53B4-9382-437475A1C8A4.dita">List of Patchable

Constants</xref>  </p> <p><b>Coding Practise</b> </p> <p>There are many aspects of coding practise

that can result in performance variations. Though such differences

might appear small, performance bottlenecks can occur where a piece

of inefficient code is executed repeatedly. By identifying where bottlenecks

exist you target specific areas of code that have a significant impact

on performance. </p> <p><xref href="GUID-49645D0A-AEA4-5D61-A6F3-633D80DCFD5B.dita">Application Performance</xref>  </p> <p><xref href="GUID-12FF05BE-F06E-58F0-909D-05CB6F7FA03E.dita">Code Efficiency</xref>  </p> </section>

<li id="GUID-EF06353C-E907-507E-8468-DC373D6E89AB"><p>Calendar: <xref href="GUID-94AC5E9C-146D-5FE7-B7B6-44AA139A6012.dita">Speeding up Agenda

Application Start-up How-To Document, in the Agenda Model engineering

documents section</xref>  </p> </li>

<li id="GUID-779BAF64-10F9-549D-AAE2-B8A13B923A13"><p>Contacts: <xref href="GUID-2E1DCE15-2F35-57E4-A279-18D1A3AB4BD3.dita">Speeding up Contacts

Application Start-up How-To Document, in the Contacts Model engineering

documents section</xref>  </p> </li>

<li id="GUID-9B7C9702-5877-51B1-87D9-573F6D9A1430"><p>Plugin Framework: <xref href="GUID-85AE95DD-D8C0-5F38-9A98-2F92328162E7.dita">Using ECOM and plug-ins

in phone ROMs</xref>  </p> </li>

<li id="GUID-97F6CBB4-928F-5EE2-857B-15999502AB98"><p>Various components: <xref href="GUID-C6C77895-91E8-5BBF-8D77-0DF6F92F1223.dita">System-level engineering

documents</xref>  </p> </li>

</ul> </section>

</conbody></concept>