mirror of https://github.com/BOINC/boinc.git
65 lines
1.7 KiB
PHP
65 lines
1.7 KiB
PHP
<?php
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require_once("docutil.php");
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page_head("Trickle messages");
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echo "
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<b>Trickle messages</b>
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let applications communicate with the server
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during the execution of a workunit.
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They are intended for applications that have long workunits (multiple days).
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<p>
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Trickle messages may from client to server or vice versa.
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Messages are XML documents.
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<h3>Trickle-up messages</h3>
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<p>
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<b>Trickle-up</b> messages go from application to server.
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They are handled by <b>trickle handler daemons</b> running on the server.
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Each message is tagged with a 'variety' (a character string).
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Each daemon handles messages of a particular variety.
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(This is used, typically, to distinguish different applications.)
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Example uses:
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<ul>
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<li>
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The application sends a trickle-up message containing
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its current CPU usage,
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so that users can be granted incremental credit
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(rather than waiting until the end of the work unit).
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<li>
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The application sends a trickle-up message
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containing a summary of the computational state,
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so that server logic can decide if the computation should be aborted.
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</ul>
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<h3>Trickle-down messages</h3>
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<p>
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<b>Trickle-down</b> messages go from server to application.
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Each one is addressed to a particular host,
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and must include an element <code><result_name></code>
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identifying the result to which the message is addressed.
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If that result is still running on the host, it is delivered to it.
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Example uses:
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<ul>
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<li>
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The server sends a message telling the application to abort.
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<li>
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The server sends a message containing the user's current total credit.
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</ul>
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<p>
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Trickle messages are asynchronous, ordered, and reliable.
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Trickle messages are conveyed in scheduler RPC messages,
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so they may not be delivered immediately after being generated.
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";
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page_tail();
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?>
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