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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57" xml:lang="en"><title>Adjustable |
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13 Performance Configuration</title><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>Various system parameters may be modified to control the way that elements |
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15 within the system behave. The parameters listed in this document have been |
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16 found to have significant impacts on important aspects of system performance. </p> |
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17 <p>In each case there is trade off, typically between speed and resource use |
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18 but sometimes between boot time and performance in steady state. The amount |
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19 of trade off varies according hardware, software and how both are used. The |
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20 only way of establishing the effect of each setting on a working device is |
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21 through systematic testing. </p> |
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22 <p>There is no common method of configuring the parameters listed here. Some |
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23 of the values must be set before compilation, others before the ROM is built. </p> |
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24 <ul> |
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25 <li id="GUID-EE04CF03-F56D-52D7-BFF4-3D3AAB7C6106"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-09C25275-5D3A-514B-8F0D-C5C1A3FA41EC">Bitmaps</xref> </p> </li> |
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26 <li id="GUID-02A6FF27-4E28-50F5-B0B7-C4BB20201FFE"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-6F89A67C-D05C-535B-B316-22EBECA7D7BF">Central Repository</xref> </p> </li> |
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27 <li id="GUID-17BCAC94-0678-5048-A33F-151B36E0E83D"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-F0EB9A69-C00B-5778-AB90-E8C78CF0E2CB">Comms Server</xref> </p> </li> |
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28 <li id="GUID-59149610-A605-5C6C-BA53-E921E2658D6C"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-4E07079A-B7B7-5020-BB15-8F31D5FAFCDA">Database Management System (DBMS)</xref> </p> </li> |
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29 <li id="GUID-31BBAE9F-7427-5925-9FE7-907EC852C366"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-0E06EE19-F1FE-5940-8167-34654BFBA90A">Domain Name Daemon</xref> </p> </li> |
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30 <li id="GUID-252ED29A-8F5A-54F2-A98C-65F48D080C61"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-BE38584C-7999-5D27-B4A2-1A7CFA82D311">Heap Configuration</xref> </p> </li> |
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31 <li id="GUID-F6E88149-0B78-5E48-8399-51268803591F"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-9F765460-7F6A-5F2A-85DE-89EBFE213B1E">Recognizer Loading</xref> </p> </li> |
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32 <li id="GUID-E5B09C3D-FF56-5D3B-B47A-B2D4EE265A86"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-9B98E4EB-28BC-5A0A-8174-7949E515AFA6">Secure Backup </xref> </p> </li> |
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33 <li id="GUID-A49DD8FE-958E-542F-98EF-7926A2A10722"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-4EC82389-6C89-5C47-BAC4-A139BCB3531E">Server shutdown behaviour</xref> </p> </li> |
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34 <li id="GUID-E792C035-38A4-561C-91CF-A23574E3E744"><p><xref href="GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57.dita#GUID-7E401451-16EB-515B-88B2-4D0D2D6C7A57/GUID-2CACB838-2E72-5723-9511-68EC1D7E3BDD">Window Server</xref> </p> </li> |
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35 </ul> |
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36 <section id="GUID-09C25275-5D3A-514B-8F0D-C5C1A3FA41EC"><title>Bitmaps</title> <p>Bitmaps |
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37 use up large amounts of memory. There are several parameters that you can |
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38 configure to reduce the amount of memory that bitmaps use. The effects that |
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39 your adjustments have will depend upon both the nature of the bitmaps used |
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40 in your system and the way that they are used. </p> <p><b>Bitmap compression ratio configuration </b> </p> <p>Bitmaps can be compressed |
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41 using algorithms that typically take advantage of blocks of common colour. |
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42 The amount that a bitmap can be compressed depends on the bitmap itself. </p> <p>A |
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43 bitmap stored in a compressed format has to be decompressed before it can |
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44 be displayed. </p> <p>A <b>compile-time macro</b>, <codeph>KCompressionThreshold</codeph>, |
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45 specifies how much reduction in size must be achievable for bitmaps to be |
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46 compressed. The theory is that if compression would only result in a small |
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47 difference in size it is a waste of time. </p> <dl> |
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48 <dlentry> |
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49 <dt>Location</dt> |
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50 <dd><p> <filepath>...\os\graphics\fbs\fontandbitmapserver\group\FBSCLI.MMP</filepath> </p> </dd> |
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51 </dlentry> |
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52 <dlentry> |
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53 <dt>Source</dt> |
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54 <dd><codeblock id="GUID-BD267125-B08B-5723-9C4F-2737882BFD1D" xml:space="preserve">/* |
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55 KCompressionThreshold is used to determine whether a bitmap gets compressed. |
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56 Values of 0 -> 256 represent 0% to 100% where 0% = no compression. |
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57 A value of 205 means that bitmaps are only compressed when the resulting size is 80% or less |
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58 of the original size. |
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59 */ |
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60 MACRO KCompressionThreshold=205 // i.e. 80% compression |
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61 </codeblock> </dd> |
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62 </dlentry> |
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63 </dl> <p>You must recompile FBServ for this change to take effect. </p> <p><b>Bitmap storage location </b> </p> <p>Bitmaps are stored in different memory |
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64 locations according to their size. </p> <ul> |
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65 <li id="GUID-08722693-3C5C-50FD-BD60-EBE2C3EC28A3"><p>Small bitmaps are stored |
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66 in a normal heap called a shared chunk. </p> </li> |
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67 <li id="GUID-9066CCC7-4872-5BEC-B754-3406E02CE234"><p>Large bitmaps are stored |
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68 in special area of memory, called the large chunk or pile, that is managed |
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69 by the font and bitmap server. </p> </li> |
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70 </ul> <p>This is because storing and deleting bitmaps, especially large ones, |
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71 leads to memory fragmentation which can prevent RAM being freed for the rest |
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72 of the system. Defragmetation, however, is a slow process, so only the large |
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73 chunk is defragmented. </p> <p>A <b>compile-time macro</b>, <codeph>KMaxLargeBitmapAlloc</codeph>, |
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74 specifies the cut-off point (in kB) at which a bitmap is considered large |
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75 and, therefore, stored in the large chunk. </p> <p>The higher the value the |
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76 larger the bitmaps stored in the shared chunk will be. This typically results |
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77 in higher RAM use, because the heap becomes more fragmented, but better overall |
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78 system performance because the defragmentation process runs less often on |
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79 the large chunk. </p> <dl> |
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80 <dlentry> |
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81 <dt>Location</dt> |
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82 <dd><p> <filepath>...\os\graphics\fbs\fontandbitmapserver\group\FBSCLI.MMP</filepath> </p> </dd> |
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83 </dlentry> |
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84 <dlentry> |
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85 <dt>Source</dt> |
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86 <dd><codeblock id="GUID-3EDA0707-66CD-563C-AB11-3FB72582CECB" xml:space="preserve">/* |
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87 configurable value to control bitmap heap defragmentation by setting large bitmap threshold |
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88 */ |
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89 MACRO KMaxLargeBitmapAlloc=0x4000 |
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90 |
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91 </codeblock> </dd> |
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92 </dlentry> |
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93 </dl> <p>You must recompile FBServ for this change to take effect. </p> <p><b>Large chunk defragmentation </b> </p> <p>Deleting large bitmaps results |
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94 in fragmentation of the large chunk (see above). </p> <p>A <b>compile-time |
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95 macro</b>, <codeph>KFreeCellCountLimit</codeph>, specifies the number of free |
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96 cells that must exist in the large chunk before it gets defragmented. </p> <dl> |
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97 <dlentry> |
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98 <dt>Location</dt> |
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99 <dd><p> <filepath>...\os\graphics\fbs\fontandbitmapserver\group\FBSCLI.MMP</filepath> </p> </dd> |
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100 </dlentry> |
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101 <dlentry> |
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102 <dt>Source</dt> |
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103 <dd><codeblock id="GUID-576D18C1-6D4F-5E39-A69D-481D29F69CEE" xml:space="preserve">/* |
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104 KFreeCellCountLimit determines when a forced foreground defragmentation will take place. |
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105 This will happen during an allocation on the FBS large bitmap chunk if the amount |
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106 of free cells exceeds the specified number. |
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107 */ |
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108 MACRO KFreeCellCountLimit=40 |
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109 </codeblock> </dd> |
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110 </dlentry> |
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111 </dl> <p>A smaller value will result in less wasted RAM but poorer performance |
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112 as the defragmentation process will run more often. </p> <p> <b>NOTE:</b> Cells |
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113 can be of variable size so this value cannot be used to calculate the amount |
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114 of wasted RAM. You can be sure, however, that the wasted RAM will be at least |
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115 (<codeph>KMaxLargeBitmapAlloc</codeph> x <codeph>KFreeCellCountLimit</codeph>). |
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116 For the default values this is 160kB. </p> <p>You must recompile FBServ for |
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117 this change to take effect. </p> <p><b>Using bitmap fonts </b> </p> <p>Using bitmap fonts instead of FreeType |
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118 fonts can reduce RAM use and increase performance at the expense of visual |
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119 appearance. FreeType fonts have to be rasterised before they can be used. |
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120 This takes time and memory. Bitmap fonts, however, can only be used in the |
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121 pre-determined range of sizes built into the ROM. </p> <p>The performance |
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122 trade off is dependant on the font rasteriser though once a font has been |
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123 rasterised it can be cached in bitmap form. </p> <p>NOTE: You can be pre-rasterise |
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124 FreeType fonts into bitmap fonts for inclusion in ROMs using the <codeph>ttf2bdf</codeph> tool. |
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125 Though the tool is supplied with the Symbian platform (as part of the <codeph>graphics_font</codeph> CBR |
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126 component) it is not supported. There may also be legal and licencing issues |
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127 to consider when pre-rasterising ronts in this way. </p> </section> |
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128 <section id="GUID-6F89A67C-D05C-535B-B316-22EBECA7D7BF"><title>Central Repository </title> <p>The |
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129 Central Repository caches individual repositories in RAM after clients have |
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130 closed their sessions. You can configure the <i>sizeof the cache</i> and the <i>length |
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131 of time that entries persist</i> by editing the central repository INI file <filepath>\private\10202be9\centrep.ini</filepath> </p> <codeblock id="GUID-D09B03B5-A74B-5EF5-B962-46756E491C48" xml:space="preserve">[CoarseGrainedCache] |
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132 size= <size in bytes> |
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133 timeout= <timeout in microseconds> </codeblock> <p>Increasing the size |
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134 of the cache and the timeout improve performance at the cost of increased |
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135 RAM use. </p> <p> <b>NOTE:</b> If the cache fills up the oldest entries are |
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136 pushed out before they timeout. </p> </section> |
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137 <section id="GUID-F0EB9A69-C00B-5778-AB90-E8C78CF0E2CB"><title>Comms Server</title> <p>You |
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138 can adjust the size of the <codeph>MBuf</codeph> pool. The <codeph>MBuf</codeph> pool |
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139 is used for creating buffers for communication data. </p> <p>The value is |
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140 set in <filepath>...\os\commsfw\commsprocess\commsrootserverconfig\etc\c32start.ini</filepath>. </p> <codeblock id="GUID-77C0F002-8BA1-5D2E-9EC6-78098940D30D" xml:space="preserve"> |
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141 [Global] |
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142 MBufPoolSize=<initial size in bytes>,<max size in bytes> //The default is MBufPoolSize=262144,262144. </codeblock> <p> <b>NOTE:</b> In |
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143 older versions of the Symbian platform only the maximum size was specified |
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144 so, for compatibility reasons, if a single value is specified it will be interpreted |
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145 as the maximum size. </p> <p>When an initial size is specified the pool grows |
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146 as necessary until it reaches the maximum size. It does not shrink, however, |
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147 so the RAM is not released until the device is rebooted. The disadvantage |
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148 of setting a very low initial pool size is that there might be insufficient |
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149 free RAM pages when it tries to grow which could cause panics. </p> </section> |
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150 <section id="GUID-4E07079A-B7B7-5020-BB15-8F31D5FAFCDA"><title>Database Management |
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151 System (DBMS)</title> <p>The size of the <b>cache</b> used by DBMS and the |
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152 size of the <b>buffer</b> used by STORE when performing disk I/O are adjustable. |
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153 Reducing their sizes reduces memory use but results in more I/O operations |
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154 which reduces performance. </p> <p>Adjust the sizes of the cache and buffer |
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155 as follows: </p> <ol id="GUID-9021FD5C-01F7-575A-9B3B-DC7289266602"> |
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156 <li id="GUID-EA542EA4-975D-5075-AD6D-46E09B37CCBA"><p>Define the constants <codeph>SYMBIAN_CUSTOM_DBMS_CACHE_SIZES</codeph> and <codeph>SYMBIAN_CUSTOM_STORE_BUFFER_SIZES</codeph> in the appropriate HRH file in <filepath>\epoc32\include\variant</filepath>. </p> </li> |
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157 <li id="GUID-2AA8EE9F-EDAD-515D-8407-8D4736A6CF15"><p>Create <filepath>...\os\persistentdata\persistentstorage\dbms\bmake\EDbms.mmh</filepath> by |
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158 copying <filepath>...\os\persistentdata\persistentstorage\dbms\bmake\EDbms_Template.mmh</filepath>. </p> <p>Edit |
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159 the newly created file and modify the following macros: </p> <ul> |
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160 <li id="GUID-00DE06B9-95F2-5DCB-A63E-1586CAE2686E"><p> <codeph>PAGE_CACHE_SIZE</codeph> - |
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161 the size of the page cache used to cache index information in a database. |
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162 It must not be less than 8 pages. </p> </li> |
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163 <li id="GUID-2182B6CC-F0CF-52F8-9986-231546A90D8C"><p> <codeph>MAX_CLUSTER_CACHE_SIZE</codeph> - |
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164 the size of the cluster cache which is used to cache row data for tables in |
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165 a database. It must not be less than 4 clusters. </p> </li> |
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166 </ul> </li> |
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167 <li id="GUID-E3FC7916-96B7-53F1-8E57-53243FFDAB78"><p>Create <filepath>...\os\persistentdata\persistentstorage\store\BMAKEEStor.mmh</filepath> by |
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168 copying <filepath>...\os\persistentdata\persistentstorage\store\BMAKE\EStor_Template.mmh</filepath>. </p> <p>Edit |
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169 the newly created file and modify the following macros: </p> <ul> |
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170 <li id="GUID-5D98A6F3-160F-5348-B85D-97E387E8AE70"><p> <codeph>DEFAULT_FILE_BUF_SIZE</codeph> This |
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171 macro sets the default file buffer size in bytes used in <xref href="GUID-418E7956-BE91-39A2-A26D-F1CA88B458AA.dita"><apiname>RFileBuf</apiname></xref> objects. |
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172 It must not be less than 1536 bytes. </p> </li> |
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173 <li id="GUID-A6CAC043-CC3E-519F-84DB-D1F9E6AB8C42"><p> <codeph>MAX_READ_AHEAD_VALUE</codeph> This |
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174 macro sets the maximum <xref href="GUID-418E7956-BE91-39A2-A26D-F1CA88B458AA.dita"><apiname>RFileBuf</apiname></xref> read-ahead value in bytes. |
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175 This defines the number of bytes read into the file buffer when buffer underflow |
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176 occurs. It must not be less than 512 bytes or greater than <codeph>DEFAULT_FILE_BUF_SIZE</codeph> </p> </li> |
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177 <li id="GUID-25FC3F98-0B4A-52E2-BF26-EDAEA0B03585"><p> <codeph>FILE_BLOCK_SIZE</codeph> This |
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178 macro sets the file-system block size for <xref href="GUID-418E7956-BE91-39A2-A26D-F1CA88B458AA.dita"><apiname>RFileBuf</apiname></xref>. It |
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179 is used in the event of a buffer underflow to perform block-aligned reads |
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180 to load the buffer. It must not be less than 512 bytes or greater then <codeph>MAX_READ_AHEAD_VALUE</codeph>. |
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181 It must also be a power of 2 </p> </li> |
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182 </ul> </li> |
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183 <li id="GUID-F7304DF3-99B5-50E5-8FA0-025A1C26317D"><p>Rebuild STORE then DBMS. </p> </li> |
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184 </ol> </section> |
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185 <section id="GUID-0E06EE19-F1FE-5940-8167-34654BFBA90A"><title>Domain Name |
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186 Daemon</title> <p>You can control the number of concurrent requests handled |
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187 by the Domain Name Daemon (DND). The DND reserves memory for these at startup |
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188 to guarantee service. Reducing the number saves RAM but slows down web page |
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189 retrieval, especially on pages with lots of in-line images. </p> <p>In the |
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190 file <filepath>...\os\networkingsrv\tcpiputils\dnd\inc\listener.h</filepath> </p> <codeblock id="GUID-3DFE4664-CAC8-5FE0-8D25-00D14D8754B3" xml:space="preserve">const TUint KDndNumResolver = 31 ;</codeblock> <p>You |
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191 can also limit the number of Link-Local Multicast Name Resolvers (LLNMR) that |
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192 get created which also saves RAM but impacts performance because fewer concurrent |
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193 DNS queries can be made </p> <p>In the file </p><filepath>...\os\networkingsrv\tcpiputils\dnd\inc\llmnrresponder.h</filepath> <codeblock id="GUID-E42FFFD4-2A9A-5D20-8171-F09AED1FEA15" xml:space="preserve">const TInt KLlmnrMaxEnabled = 15 ; </codeblock> <p> <b>NOTE:</b> You |
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194 must ensure that there is at least one resolver enabled for each LLMNR-enabled |
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195 network interface (NIF). </p> </section> |
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196 <section id="GUID-BE38584C-7999-5D27-B4A2-1A7CFA82D311"><title>Heap Configuration</title> <p><b>Minimum heap cell size </b> </p> <p>You can set the minimum heap cell |
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197 size used by the <xref href="GUID-EFAFDD75-7E59-306A-882D-317F5564979E.dita"><apiname>RHeap</apiname></xref> class. This has an impact on where |
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198 new allocations are placed in the heap. You can set values for both the kernel |
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199 heap and the user heap. </p> <p>The effect of changing the value is difficult |
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200 to predict and there is not a simple relationship between size and RAM use |
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201 or size and performance. In general, however, a larger value will result in |
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202 faster performance and greater RAM use. </p> <p>Typical values to experiment |
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203 with are 0, 4, 8, 16, 32 and 64. </p> <p>You set the value using a <codeph>patchdata</codeph> statement |
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204 in an OBY (or IBY) file. </p> <codeblock id="GUID-76A70134-04D6-57B1-8F1D-7C7BF7813B3B" xml:space="preserve"> |
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205 patchdata [ekern.exe|euser.dll] @ KHeapMinCellSize <NewValueForTheConstData> |
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206 </codeblock> <p>For example </p> <codeblock id="GUID-34B89B58-109B-5DFF-A91F-D1C50866CE54" xml:space="preserve"> |
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207 patchdata ekern.exe @ KHeapMinCellSize 32 |
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208 |
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209 patchdata euser.dll @ KHeapMinCellSize 32 |
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210 </codeblock> <p><b>Hysteresis window size </b> </p> <p>You can configure how the memory allocated |
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211 by the <xref href="GUID-EFAFDD75-7E59-306A-882D-317F5564979E.dita"><apiname>RHeap</apiname></xref> class is returned to the system. </p> <p>The |
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212 heap grows in fixed size chunks. You can specify how quickly it shrinks (the |
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213 amount of hysteresis) by setting <codeph>KHeapShrinkHysRatio</codeph>. </p> <p>The |
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214 value of <codeph>KHeapShrinkHysRatio</codeph> is multiplied with the size |
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215 of the growth chunk to establish the hysteresis value. When heap cells are |
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216 freed the system waits until the number of free cells reaches the hysteresis |
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217 value before releasing the memory. </p> <p>The default value of <codeph>KHeapShrinkHysRatio</codeph> is |
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218 2.0. Reducing the value towards 1 frees memory more quickly. Values of 1 or |
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219 less result in no hysteresis. More hysteresis results in faster performance, |
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220 as heap allocations occur less often, but more RAM use. </p> <p>You set the |
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221 value using a <codeph>patchdata</codeph> statement in an OBY (or IBY) file. |
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222 For example, </p> <codeblock id="GUID-FE3EAA41-A9EE-5659-A57F-6186AE22BF65" xml:space="preserve"> |
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223 patchdata ekern.exe @ KHeapShrinkHysRatio 1.5 |
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224 |
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225 patchdata euser.dll @ KHeapShrinkHysRatio 1.5 |
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226 </codeblock> </section> |
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227 <section id="GUID-9F765460-7F6A-5F2A-85DE-89EBFE213B1E"><title>Recognizer |
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228 Loading</title> <p>You can configure the Apparc server to load recognizer |
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229 plugins at startup or on demand. Loading on demand reduces RAM consumption |
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230 and boot time. The trade-off is that the first use of each recognizer takes |
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231 longer to complete as it needs to be loaded before it can be used. Because |
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232 recognizers typically get used several times in quick succession the impact |
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233 of the trade off can be reduced by using a timer to defer unloading </p> <p>You |
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234 can enable or disable load-on-demand and specify the delay before unloading |
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235 using the <codeph>patchdata</codeph> statement in an OBY (or IBY) file. </p> <codeblock id="GUID-17741E7B-5EF8-52F9-9DED-C5482B78EDEE" xml:space="preserve">patchdata apserv.dll @ KApaLoadDataRecognizersOnDemand <newvalue> </codeblock> <p>The |
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236 default <codeph>newvalue</codeph> is 0 which means that recognizers are loaded |
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237 at boot. A value of 1 specifies that recognizers will be loaded on demand. </p> <codeblock id="GUID-D398EA48-F84C-528D-B0B1-40B8A8E6F1A1" xml:space="preserve">patchdata apserv.dll @ KApaUnloadRecognizersTimeout <newvalue> </codeblock> <p>The |
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238 default<codeph>newvalue</codeph> is 10000000 (10 seconds in milliseconds). </p> </section> |
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239 <section id="GUID-9B98E4EB-28BC-5A0A-8174-7949E515AFA6"><title>Secure Backup |
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240 Optimisation</title> <p>The secure backup engine uses a shared chunk to communicate |
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241 information efficiently between client and server components. You can set |
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242 the size of the chunk, and other parameters, in a file called <filepath>sbeconfig.xml</filepath> in |
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243 the private directory of the secure backup engine. The default size of the |
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244 chunk is 2MB. </p> <codeblock id="GUID-08DAB844-88CF-560B-93E0-718CBEA0A9C4" xml:space="preserve"> |
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245 <?xml version="1.0" encoding="UTF-16" standalone="yes"?> |
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246 <sbe_config> |
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247 <heap size = "2097152" max_retries = "5" reduction_factor = "2"/> |
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248 <central_repository uid = "0x10202BE9"/> |
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249 <exclude_drives list = "z"/> |
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250 </sbe_config> |
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251 </codeblock> </section> |
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252 <section id="GUID-4EC82389-6C89-5C47-BAC4-A139BCB3531E"><title> Server shutdown |
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253 behaviour</title> <p>The shutdown behaviour of servers has a large impact |
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254 on RAM and performance characteristics. If a server is always running it can |
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255 respond faster to each request but requires RAM all the time. A transitive |
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256 server is one which shuts down when it has no active connections. A transitive |
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257 server uses RAM only when necessary but its performance will vary according |
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258 to whether it needs to be started. </p> <p>You can configure the shutdown |
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259 behaviour of several key Symbian servers. </p> <p><b>Message Server </b> </p> <p>Symbian provides two versions of the Message |
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260 Server: an always-on version and a transitive one. You can select which one |
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261 to include in your ROM by editing <filepath>../generic/messaging/framework/server/group/messageserver.iby</filepath> </p> <ul> |
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262 <li id="GUID-563A829D-7ED3-50E0-A90C-472D2EBEA65C"><p>For always-on include <filepath>msgs.dll</filepath> in |
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263 your ROM </p> </li> |
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264 <li id="GUID-42CD2F3D-9552-5FC7-910E-3B8D6EE8892C"><p>For transitive behaviour |
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265 include <filepath>msgs_autoshutdown.dll</filepath> in your ROM </p> </li> |
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266 </ul> <p><b>Contacts Server </b> </p> <p>The behaviour of the Contacts Server is determined |
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267 by a command line argument passed to <filepath>cntsrv.exe</filepath>. </p> <p>The |
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268 default behaviour is transitive. For always-on behaviour you must start the |
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269 server use the <codeph>-nontransient</codeph> option in your system startup |
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270 file. </p> <codeblock id="GUID-85079652-9D30-5B44-BCDF-8DB41759B2CC" xml:space="preserve"> |
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271 START_PROCESS_INFO |
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272 { |
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273 path = "Z:\\sys\\bin\\cntsrv.exe"; |
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274 args = "-nontransient"; |
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275 ... |
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276 }</codeblock> <p><b>Agenda Server </b> </p> <p>The behaviour of the Agenda Server is determined |
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277 by a command line argument passed to <filepath>agsvexe.exe</filepath>. </p> <p>The |
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278 default behaviour is transitive. For always-on behaviour you must start the |
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279 server use the <codeph>-nontransient</codeph> option in your system startup |
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280 file. </p> <codeblock id="GUID-DF1BBB3B-8A6E-5F63-B91C-9E4B9A952331" xml:space="preserve"> |
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281 START_PROCESS_INFO |
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282 { |
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283 path = "Z:\\sys\\bin\\agsvexe.exe"; |
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284 args = "-nontransient"; |
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285 ... |
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286 }</codeblock> </section> |
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287 <section id="GUID-2CACB838-2E72-5723-9511-68EC1D7E3BDD"><title>Window Server</title> <p><b>Flicker Free Redraw and Transparency </b> </p> <p>You can configure the |
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288 drawing behaviour of the window server by enabling or disabling support for<b>flicker |
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289 free redraw</b> and <b>transparency</b>. </p> <p>The window server is generally |
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290 configured to allocate two full-screen bitmaps (which consume over 140kB each |
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291 on a device with a normal resolution display). </p> <ul> |
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292 <li id="GUID-E42668D2-7D67-527A-9A4A-A84A58781701"><p>An off-screen bitmap |
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293 to reduce redraw flicker. Drawing commands between <codeph>BeginRedraw</codeph> and <codeph>EndRedraw</codeph> commands |
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294 are committed to the off-screen bitmap. Only when <codeph>EndRedraw</codeph> is |
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295 called does the window server update the screen with the contents of the off-screen |
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296 bitmap. </p> </li> |
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297 <li id="GUID-E4334927-57C3-5A1B-A6EF-549AFD203429"><p>A transparency bitmap |
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298 to support transparent windows. </p> </li> |
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299 </ul> <p>The allocation of these bitmaps can be configured in <filepath>Wsini.ini</filepath>. </p> <ul> |
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300 <li id="GUID-B529F499-7FCC-5076-859C-3D0ABF8E0B9B"><p>The presence of the |
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301 keyword <codeph>FLICKERFREEREDRAW</codeph> causes the off-screen bitmap to |
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302 be allocated. </p> </li> |
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303 <li id="GUID-751FB913-C942-5F8D-9A36-0B2727941977"><p>The presence of the |
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304 keyword <codeph>TRANSPARENCY</codeph> causes <b>both</b> the off-screen and |
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305 transparency bitmaps to be allocated. </p> </li> |
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306 <li id="GUID-7D32B174-8E33-5292-9096-3EF0EB825C60"><p>If neither keyword is |
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307 present no full-screen bitmaps are allocated. </p> </li> |
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308 </ul> <p> </p> <p>In practice flicker free redraw makes a noticeable improvement |
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309 to most UIs. If a UI uses transparent windows both bitmaps must be enabled. </p> <p><b>The default window server command buffer </b> </p> <p>Each connection |
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310 to the window server has a command buffer so that the number of inter-process |
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311 calls can be reduced. The buffer has a default size (<codeph>EClientBufferSize</codeph>) |
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312 which is typically the minimum of 640 bytes. Applications can override the |
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313 default whenever they create an <codeph>RWsSession</codeph>. </p> <p>The default |
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314 buffer size is defined in <filepath>...\os\graphics\windowing\windowserver\SERVER\w32cmd.h</filepath> </p> <p>The |
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315 benefit of a small buffer is reduced RAM use. The benefits of a bigger buffer |
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316 are reduced IPC (so drawing is more efficient) and reduced flicker. </p> <p> <b>NOTE:</b> Increasing |
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317 the buffer size to reduce flicker is less effective than using the <codeph>FICKERFREEREDRAW</codeph> feature |
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318 described above. </p> </section> |
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319 </conbody></concept> |