《PHP實例：round robin權重輪循算法php實現代碼》要點：
本文介紹了PHP實例：round robin權重輪循算法php實現代碼，希望對您有用。如果有疑問，可以聯系我們。
PHP學習先上代碼,采用php腳本語言
PHP學習
<?php
/*
* Copyright (C) FatHong
*/
/* 數據初始化,weight: 權重 */
$hosts['a'] = array('weight' => 5, 'current_weight' => 0, 'count' => 0);
$hosts['b'] = array('weight' => 3, 'current_weight' => 0, 'count' => 0);
$hosts['c'] = array('weight' => 2, 'current_weight' => 0, 'count' => 0);
$result = array();
/* 模擬10次 */
for ($i = 0; $i < 10; $i++) {
round_robin($hosts, $result);
}
/* 輸出結果 */
print_r($result);
/* round robin 輪循 */
function round_robin(&$hosts, &$result)
{
$total = 0;
$best = null;
foreach ($hosts as $key => $item) {
$current = &$hosts[$key];
$weight = $current['weight'];
$current['current_weight'] += $weight;
$total += $weight;
if ( ($best == null) || ($hosts[$best]['current_weight'] <
$current['current_weight']) )
{
$best = $key;
}
}
$hosts[$best]['current_weight'] -= $total;
$hosts[$best]['count']++;
$result[] = $best;
}
PHP學習輸出結果：
PHP學習Array
(
[0] => a
[1] => b
[2] => c
[3] => a
[4] => a
[5] => b
[6] => a
[7] => c
[8] => b
[9] => a
)
PHP學習負載均衡的服務器中,其實現算法有種是round-robin權重輪循,就是后端的服務器列表中,給每個服務器標上權重,代表它被采用的機率.
PHP學習這段代碼把最簡潔的流程剝離出來,沒考慮后端掛起等情況,可以知道它是怎么實現的,僅供參考.
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