mirror of https://github.com/BOINC/boinc.git
138 lines
3.7 KiB
PHP
138 lines
3.7 KiB
PHP
<?php
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require_once("docutil.php");
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page_head("Compound applications");
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echo "
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<h3>Compound applications</h3>
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A <b>compound application</b> consists of a <b>main program</b>
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and one or more <b>worker programs</b>.
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The main program executes the worker programs in sequence,
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and maintains a 'main state file' that records
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which worker programs have completed.
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The main program assigns to each worker program
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a subrange of the overall 'fraction done' range of 0..1.
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For example, if there are two worker programs with equal runtime,
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the first would have range 0 to 0.5 and the second
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would have range 0.5 to 1.
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<p>
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The BOINC API provides a number of functions,
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and in developing a compound application you must decide
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whether these functions are to be performed by the main or worker program.
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The functions are represented by flags in the BOINC_OPTIONS structure.
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Each flag must be set in either the main or worker programs, but not both.
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<pre>
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struct BOINC_OPTIONS {
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int main_program;
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int check_heartbeat;
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int handle_trickle_ups;
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int handle_trickle_downs;
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int handle_process_control;
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int handle send_status_msgs;
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int direct_process_action;
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};
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int boinc_init_options(BOINC_OPTIONS&);
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</pre>
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";
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list_start();
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list_item("main_program",
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"Set this in the main program."
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);
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list_item("check_heartbeat",
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"If set, the program monitors 'heartbeat' messages from the core client.
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If the heartbeat stops, the result depends on the direct_process_action
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flag (see below)."
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);
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list_item("handle_trickle_ups",
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"If set, the program can send trickle-up messages."
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);
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list_item("handle_trickle_downs",
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"If set, the program can receive trickle-down messages."
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);
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list_item("handle_process_control",
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"If set, the program will handle 'suspend', 'resume', and 'quit'
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messages from the core client.
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The action depends on the direct_process_action flag."
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);
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list_item("send_status_msgs",
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"If set, the program will report its CPU time and fraction
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done to the core client. Set in worker programs."
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);
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list_item("direct_process_action",
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"If set, the program will respond to quit messages and heartbeat
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failures by exiting, and will respond to suspend and resume
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messages by suspending and resuming.
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Otherwise, these events will result in changes to
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the BOINC_STATUS structure,
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which can be polled using boinc_get_status()."
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);
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list_end();
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echo "
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<p>
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Typical main program logic is:
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<pre>
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BOINC_OPTIONS options;
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options.main_program = true;
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...
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boinc_init_options(options)
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read main state file
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for each remaining worker program:
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aid.fraction_done_start = x
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aid.fraction_done_end = y
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boinc_write_init_data_file()
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run the app
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wait for the app to finish
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poll
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write main state file
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if last app:
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break
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boinc_parse_init_data_file() // reads CPU time from app_init.xml file
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boinc_finish()
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</pre>
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where x and y are the appropriate fraction done range limits.
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<p>
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Typical worker program logic is:
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<pre>
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BOINC_OPTIONS options;
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options.main_program = false;
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...
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boinc_init_options(options);
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...
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do work, calling boinc_fraction_done() with values from 0 to 1,
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and boinc_time_to_checkpoint(), occasionally
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...
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boinc_finish(); // this writes final CPU time to app_init.xml file
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</pre>
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<p>
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If the graphics is handled in a program that runs concurrently with
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the worker programs, it must also call
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<code>boinc_init_options()</code>, typically with all options false,
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then <code>boinc_init_graphics()</code>,
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and eventually <code>boinc_finish()</code>.
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<p>
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If the main program is responsible for reporting application status
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to the core client, it should periodically call
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<pre>
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boinc_report_app_status(
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double cpu_time, // CPU time since start of WU
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double checkpoint_cpu_time, // CPU time at last checkpoint
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double fraction_done
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);
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</pre>
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";
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page_tail();
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?>
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