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MDL-67363 task: Add adhoc task quality of service balancing

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This commit is contained in:
Brendan Heywood
2019-12-03 12:21:10 +11:00
parent 800563e415
commit 4971da0bfa
2 changed files with 237 additions and 0 deletions
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lib/classes/task/manager.php
+71
View File
@@ -471,6 +471,75 @@ class manager {
return $tasks;
}
/**
* Ensure quality of service for the ad hoc task queue.
*
* This reshuffles the adhoc tasks queue to balance by type to ensure a
* level of quality of service per type, while still maintaining the
* relative order of tasks queued by timestamp.
*
* @param array $records array of task records
* @return void
*/
public static function ensure_adhoc_task_qos(array $records): array {
$count = count($records);
if ($count == 0) {
return $records;
}
$queues = []; // This holds a queue for each type of adhoc task.
$limits = []; // The relative limits of each type of task.
$limittotal = 0;
// Split the single queue up into queues per type.
foreach ($records as $record) {
$type = $record->classname;
if (!array_key_exists($type, $queues)) {
$queues[$type] = [];
}
if (!array_key_exists($type, $limits)) {
$limits[$type] = 1;
$limittotal += 1;
}
$queues[$type][] = $record;
}
$qos = []; // Our new queue with ensured quality of service.
$seed = $count % $limittotal; // Which task queue to shuffle from first?
do {
$shuffled = 0;
// Now cycle through task type queues and interleaving the tasks
// back into a single queue.
foreach ($limits as $type => $limit) {
// Just interleaving the queue is not enough, because after
// any task is processed the whole queue is rebuilt again. So
// we need to deterministically start on different types of
// tasks so that *on average* we rotate through each type of task.
//
// We achieve this by using a $seed to start moving tasks off a
// different queue each time. The seed is based on the task count
// modulo the number of types of tasks on the queue. As we count
// down this naturally cycles through each type of record.
if ($seed < 1) {
$shuffled = 1;
$seed += 1;
continue;
}
$task = array_splice($queues[$type], 0, 1);
$qos = array_merge($qos, $task);
// Stop if we didn't move any tasks onto the main queue.
$shuffled += count($task);
}
} while ($shuffled > 0);
return $qos;
}
/**
* This function will dispatch the next adhoc task in the queue. The task will be handed out
* with an open lock - possibly on the entire cron process. Make sure you call either
@@ -491,6 +560,8 @@ class manager {
$params = array('timestart1' => $timestart);
$records = $DB->get_records_select('task_adhoc', $where, $params);
$records = self::ensure_adhoc_task_qos($records);
foreach ($records as $record) {
if ($lock = $cronlockfactory->get_lock('adhoc_' . $record->id, 0)) {
lib/tests/task_manager_test.php
+166
View File
@@ -0,0 +1,166 @@
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* This file contains the unit tests for the task manager.
*
* @package core
* @copyright 2019 Brendan Heywood <[email protected]>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
/**
* This file contains the unit tests for the task manager.
*
* @copyright 2019 Brendan Heywood <[email protected]>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class core_task_manager_testcase extends advanced_testcase {
public function test_ensure_adhoc_task_qos_provider() {
return [
[
[],
[],
],
// A queue with a lopside initial load that needs to be staggered.
[
[
(object)['id' => 1, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 2, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 3, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 4, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
],
[
(object)['id' => 1, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 2, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 3, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 4, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
],
],
// The same lopsided queue but now the first item is gone.
[
[
(object)['id' => 2, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 3, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 4, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
],
[
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 2, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 3, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 4, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
],
],
// The same lopsided queue but now the first two items is gone.
[
[
(object)['id' => 3, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 4, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
],
[
(object)['id' => 3, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 4, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
],
],
// The same lopsided queue but now the first three items are gone.
[
[
(object)['id' => 4, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
],
[
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 4, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
],
],
[
[
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
],
[
(object)['id' => 5, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 7, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 6, 'classname' => '\core\task\asynchronous_backup_task'],
(object)['id' => 8, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
(object)['id' => 9, 'classname' => '\tool_dataprivacy\task\process_data_request_task'],
],
],
];
}
/**
* Test that the Quality of Service reordering works.
*
* @dataProvider test_ensure_adhoc_task_qos_provider
*
* @param array $input array of tasks
* @param array $expected array of reordered tasks
* @return void
*/
public function test_ensure_adhoc_task_qos(array $input, array $expected) {
$this->resetAfterTest();
$result = \core\task\manager::ensure_adhoc_task_qos($input);
$this->assertEquals($expected, $result);
}
}