[lttv.git] / tags / lttv-0.10.0-pre15-12082008 / doc / developer / developer_guide / html / x46.html

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>2.2. Why an event driven trace reader ?</A
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>&#13;The complexity of synchronizing the tracesets is then hidden to the viewer. Some
future plans involve to be able to put many traces together in a trace set.
Before this becomes possible, the time of each trace must be synchronized in
some way. Some work is actually done to create a module that uses the network
traffic shared by different computers to synchronize the time of different
traces.
</P
><P
>&#13;In order to make each module integrate well with each other, we made the trace
reader a simple hook caller. For each event it reads, it just calls the hook
lists for this event. For each event, it calls the by_id specific hooks
registered for this event and also the "main" hooks, registered for all events.
Note that the two hook lists are merged when called so the priority of the
hooks of each list is respected. For example, a hook of higher priority (20) in
the main list will be called before a hook of lower priority (40) from the
by_id specific list.
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Commit	Line	Data
5750899b	1	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
	2	<HTML
	3	><HEAD
	4	><TITLE
	5	>Why an event driven trace reader ?</TITLE
	6	><META
	7	NAME="GENERATOR"
	8	CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
	9	REL="HOME"
	10	TITLE="Linux Trace Toolkit Viewer Developer Guide"
	11	HREF="index.html"><LINK
	12	REL="UP"
	13	TITLE="How to use the Linux Trace Toolkit Viewer's Reading Context"
	14	HREF="c40.html"><LINK
	15	REL="PREVIOUS"
	16	TITLE="How to use the Linux Trace Toolkit Viewer's Reading Context"
	17	HREF="c40.html"><LINK
	18	REL="NEXT"
	19	TITLE="Using the reading context"
	20	HREF="x50.html"></HEAD
	21	><BODY
	22	CLASS="sect1"
	23	BGCOLOR="#FFFFFF"
	24	TEXT="#000000"
	25	LINK="#0000FF"
	26	VLINK="#840084"
	27	ALINK="#0000FF"
	28	><DIV
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	31	SUMMARY="Header navigation table"
	32	WIDTH="100%"
	33	BORDER="0"
	34	CELLPADDING="0"
	35	CELLSPACING="0"
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	39	ALIGN="center"
	40	>Linux Trace Toolkit Viewer Developer Guide</TH
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	46	VALIGN="bottom"
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	50	>Prev</A
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	52	><TD
	53	WIDTH="80%"
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	55	VALIGN="bottom"
	56	>Chapter 2. How to use the Linux Trace Toolkit Viewer's Reading Context</TD
	57	><TD
	58	WIDTH="10%"
	59	ALIGN="right"
	60	VALIGN="bottom"
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	62	HREF="x50.html"
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	64	>Next</A
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66	></TR
67	></TABLE
68	><HR
69	ALIGN="LEFT"
70	WIDTH="100%"></DIV
71	><DIV
72	CLASS="sect1"
73	><H1
74	CLASS="sect1"
75	><A
76	NAME="AEN46"
77	>2.2. Why an event driven trace reader ?</A
78	></H1
79	><P
80	> The complexity of synchronizing the tracesets is then hidden to the viewer. Some
81	future plans involve to be able to put many traces together in a trace set.
82	Before this becomes possible, the time of each trace must be synchronized in
83	some way. Some work is actually done to create a module that uses the network
84	traffic shared by different computers to synchronize the time of different
85	traces.
86	</P
87	><P
88	> In order to make each module integrate well with each other, we made the trace
89	reader a simple hook caller. For each event it reads, it just calls the hook
90	lists for this event. For each event, it calls the by_id specific hooks
91	registered for this event and also the "main" hooks, registered for all events.
92	Note that the two hook lists are merged when called so the priority of the
93	hooks of each list is respected. For example, a hook of higher priority (20) in
94	the main list will be called before a hook of lower priority (40) from the
95	by_id specific list.
96	</P
97	></DIV
98	><DIV
99	CLASS="NAVFOOTER"
100	><HR
101	ALIGN="LEFT"
102	WIDTH="100%"><TABLE
103	SUMMARY="Footer navigation table"
104	WIDTH="100%"
105	BORDER="0"
106	CELLPADDING="0"
107	CELLSPACING="0"
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110	WIDTH="33%"
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112	VALIGN="top"
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114	HREF="c40.html"
115	ACCESSKEY="P"
116	>Prev</A
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120	ALIGN="center"
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125	>Home</A
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134	>Next</A
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142	>How to use the Linux Trace Toolkit Viewer's Reading Context</TD
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150	>Up</A
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156	>Using the reading context</TD
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160	></BODY
161	></HTML
162	>