x-glossary.html

vxworks相关论文

<dd><p class="Body"><a name="90167"> </a>This is the target activity of writing information about events to the WindView event buffer as the events occur. You start event logging with the <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">Start WV </font></b>button in the <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">Control </font></b>window or with the <b class="routine"><i class="routine">wvEvtLogEnable</i></b><b>(&nbsp;)</b> routine.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90173">event-logging level</a></i></h5>
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<dd><p class="Body"><a name="90174"> </a>The event-logging facility operates in one of three user-enabled event-logging levels. These levels are differentiated by the amount of information logged for each event. At the lowest level (the CSE level), events that result in context switches are logged. At the next level (the <i class="term">TST l</i>evel), events that result in task state transitions are logged. At the highest level (the AIL level), any actions that occur to any of the objects that you have instrumented are logged. When any of these event-logging levels is active, you can add application-specific events; see user-generated events.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90181">eventpoint</a></i></h5>
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<dd><p class="Body"><a name="90183"> </a>Eventpoints are WindView-specific facilities that are analogous to breakpoints. They are locations in a program that cause WindView to display a user event icon when they are "hit" (that is, executed). Eventpoints are inserted dynamically from the Tornado shell with the <b class="routine"><i class="routine">e</i></b><b>(&nbsp;)</b> routine. See also user-generated events.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90188">event pop-up menu</a></i></h5>
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<dd><p class="Body"><a name="90190"> </a>The event pop-up menu provides commands for navigating the view graph and for displaying event information. Open it by right-clicking on any event icon in the view graph. </p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90196">event port number</a></i></h5>
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<dd><p class="Body"><a name="90197"> </a>This is the host port over which the WindView GUI or <b class="command">evtRecv</b> tool listens for connections from the target; specifically, WindView listens for event data from the upload task, <b class="task">tWVUpload</b>. The default event port number is 6164.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90203">event upload mode</a></i></h5>
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<dd><p class="Body"><a name="90204"> </a>The event buffer upload mode is set by selecting the desired mode in the <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">Control Properties</font></b> dialog box. The options are: deferred upload mode, continuous upload mode, and post-mortem mode. The modes differ by whether data is uploaded from the target to the host as it is collected or on request, and by where the target buffers are located in memory.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90210">evtRecv tool</a></i></h5>
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<dd><p class="Body"><a name="90212"> </a>This is a host tool supplied with WindView that allows you to collect an event log in a host file without the target overhead of a file system. You can later import the log into the GUI with the <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">Open</font></b> command in the <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">File</font></b> menu.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90216">exception</a></i></h5>
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<dd><p class="Body"><a name="90217"> </a>An exception is an error in program code or data, such as an illegal instruction, a bus error, or a divide-by-zero error.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90220">executing state</a></i></h5>
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<dd><p class="Body"><a name="90225"> </a>A task or other context is in the executing state (shown by the <img class="figure" border="0" src="images/x-glossary7.gif">
 stipple) if it has control of the processor. For a task to be in the executing state, there must be no interrupts to service, the task must be the highest-priority ready task in the system, and there must be no other tasks with preemption locking enabled. ISRs are in the executing state after their interrupt has been acknowledged by the kernel; if there is more than one ISR to service, the one at the processor's highest interrupt level executes. The idle loop is in the executing state when there are no tasks to run and no ISRs to service. See also current context, task state, task state transition.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90236">execution thread</a></i></h5>
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<dd><p class="Body"><a name="90238"> </a>See thread of execution.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90240">fd</a></i></h5>
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<dd><p class="Body"><a name="90242"> </a>See file descriptor.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90245">file descriptor</a></i></h5>
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<dd><p class="Body"><a name="90247"> </a>A file descriptor (<i class="acronym_lc">fd</i>) is a handle that allows the I/O system to reference a particular file. <i class="acronym_lc">Fd</i>s are returned by the <b class="routine"><i class="routine">open</i></b><b>(&nbsp;)</b> and <b class="routine"><i class="routine">creat</i></b><b>(&nbsp;)</b> routines. Three <i class="acronym_lc">fd</i>s are reserved and have special meanings: 0 for standard input, 1 for standard output, 2 for standard error output. Because <i class="acronym_lc">fd</i>s are built on top of semaphores, <i class="acronym_lc">fd</i>-related operations are displayed in WindView as semaphore operations.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90251">Filter Events/States dialog box</a></i></h5>
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<dd><p class="Body"><a name="90253"> </a>The <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">Filter Events/States</font></b> dialog box allows you to select which types of events and which context states are displayed in the view graph. It does not affect what data is logged. Open this dialog box by selecting <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">Filter Events</font></b> in the main <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">View</font></b> menu or by clicking the <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">Filter Events</font></b> button on the WindView toolbar. </p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90259">GUI</a></i></h5>
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<dd><p class="Body"><a name="90261"> </a>Graphical User Interface: the portion of WindView running on the host with which you view event data. </p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90265">host</a></i></h5>
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<dd><p class="Body"><a name="90267"> </a>The host is the platform on which you develop your real-time system and on which the main component of WindView runs. This allows you to use familiar development tools while minimizing the amount of target resources consumed.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90271">host event buffer</a></i></h5>
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<dd><p class="Body"><a name="90274"> </a>The buffer on the host that temporarily holds the event data before it is processed by WindView when you are using the GUI to collect event data.<b> </b></p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90277">idle loop</a></i></h5>
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<dd><p class="Body"><a name="90280"> </a>When there are no tasks ready to execute and no interrupts to service, the kernel enters its idle loop. In this "state," the kernel services interrupts and continually checks to see if a task is ready to run. Analyzing the amount of time your application is idle can help you fine-tune the application: too much time in the idle loop may mean the application is not using the CPU efficiently; too little time may mean that the application is interrupted too often to run effectively.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90284">inherited state</a></i></h5>
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<dd><p class="Body"><a name="90291"> </a>A task is in the inherited state (shown by the <img class="figure" border="0" src="images/x-glossary8.gif">
 stipple) when its priority has been increased because it owns a mutual exclusion semaphore that has priority inheritance enabled and a higher-priority task is waiting for that semaphore.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90296">instrumented code</a></i></h5>
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<dd><p class="Body"><a name="90297"> </a>Instrumented code is software that has been modified to provide information about its own operation. In the case of the <i class="emphasis">wind</i> kernel, this information is event data that contains a record of the significant moments in the flow of control within a real-time system. In the case of the additional instrumented libraries, this information is event information that contains a record of supporting, non-kernel functions such as I/O and memory management. Application code can be instrumented with the <b class="routine"><i class="routine">wvEvent</i></b><b>(&nbsp;)</b> and <b class="routine"><i class="routine">e</i></b><b>(&nbsp;)</b> routines; see user-generated events.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90304">instrumented object</a></i></h5>
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<dd><p class="Body"><a name="90305"> </a>An instrumented object is an object for which all operations that occur to it are logged to the WindView event buffer, including creation, gives or sends, takes or receives, and deletion operations. You specify which types of objects are to be instrumented with the <b class="guiLabel"><font face="Helvetica, sans-serif" size="-1" class="sans">Collection Control</font></b> dialog box. You can specify specific objects with the <b class="routine"><i class="routine">wvObjInst</i></b><b>(&nbsp;)</b>, <b class="routine"><i class="routine">wvSigInst</i></b><b>(&nbsp;)</b>, and <b class="routine"><i class="routine">wvObjInstModeSet</i></b><b>(&nbsp;)</b> WindView routines.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90308">interrupt</a></i></h5>
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<dd><p class="Body"><a name="90309"> </a>An interrupt is a "message" from hardware that lets the microprocessor know that something has occurred in the external world. For example, the microprocessor may receive an interrupt when a clock tick occurs or when a character is received on a serial port. See also interrupt service routine (ISR).</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90313">interrupt handler</a></i></h5>
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<dd><p class="Body"><a name="90315"> </a>See interrupt service routine (ISR).</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90318">interrupt latency</a></i></h5>
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<dd><p class="Body"><a name="90319"> </a>Interrupt latency is the longest amount of time during which the processor's ability to respond to interrupts is inhibited. Both the hardware and software architecture contribute to interrupt latency. Hardware influences on interrupt latency include such things as prioritizing interrupt requests and preventing interrupt handling until the completion of lengthy instructions. Software influences stem from disabling interrupt response with <b class="routine"><i class="routine">intLock</i></b><b>(&nbsp;)</b> for mutual exclusion.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90325">interrupt level</a></i></h5>
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<dd><p class="Body"><a name="90327"> </a>Interrupts arrive at the microprocessor at various levels; these levels and their effects are determined by the CPU architecture.</p>
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<dd><font face="Helvetica, sans-serif" size="-1" class="sans">
<h5 class="HU"><i><a name="90330">interrupt lock</a></i></h5>
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