Weighted Round-Robin Scheduling - Revision history

Wensong at 10:05, 5 November 2005

2005-11-05T10:05:30Z

Wensong at 01:48, 30 July 2005

2005-07-30T01:48:29Z

Wensong at 15:33, 25 July 2005

2005-07-25T15:33:26Z

Wensong at 10:35, 20 July 2005

2005-07-20T10:35:26Z

Wensong at 16:05, 19 July 2005

2005-07-19T16:05:02Z

New page

[[Category:Job Scheduling Algorithms]]

@@ Line 25: / Line 25: @@
 In an optimized implementation of the weighted round-robin scheduling, a scheduling sequence will be generated according to the server weights after the rules of [[IPVS]] are modified. The network connections are directed to the different real servers based on the scheduling sequence in a round-robin manner.
-The weighted round-robin scheduling is better than the round-robin scheduling, when the processing capacity of real servers are different. However, it may lead to dynamic load imbalance among the real servers if the load of the requests vary highly. In short, there is the possibility that a majority of requests requiring large responses may be directed to the same real server.
+The weighted round-robin scheduling is better than the [[Round-Robin Scheduling|round-robin scheduling]], when the processing capacity of real servers are different. However, it may lead to dynamic load imbalance among the real servers if the load of the requests vary highly. In short, there is the possibility that a majority of requests requiring large responses may be directed to the same real server.
-Actually, the round-robin scheduling is a special instance of the weighted round-robin scheduling, in which all the weights are equal.
+Actually, the [[Round-Robin Scheduling|round-robin scheduling]] is a special instance of the weighted round-robin scheduling, in which all the weights are equal.
 [[Category:Job Scheduling Algorithms]]

@@ Line 8: / Line 8: @@
   while (true) {
-   i = (i + 1) mod n;
+     i = (i + 1) mod n;
-   if (i == 0) {
+     if (i == 0) {
-     cw = cw - gcd(S);
+         cw = cw - gcd(S);
-     if (cw <= 0) {
+         if (cw <= 0) {
-       cw = max(S);
+             cw = max(S);
-       if (cw == 0)
+             if (cw == 0)
-         return NULL;
+             return NULL;
-−
+         }
-−
+     }
-   if (W(Si) >= cw)
+     if (W(Si) >= cw)
-     return Si;
+         return Si;
+  }

@@ Line 1: / Line 1: @@
-The weighted round-robin scheduling is designed to better handle servers with different processing capacities. Each server can be assigned a weight, an integer value that indicates the processing capacity. Servers with higher weights receive new connections first than those with less weights, and servers with higher weights get more connections than those with less weights and servers with equal weights get equal connections. For example, the real servers, A, B and C, have the weights, 4, 3, 2 respectively, a good scheduling sequence will be AABABCABC in a scheduling period (mod sum(Wi)).
+The weighted round-robin scheduling is designed to better handle servers with different processing capacities. Each server can be assigned a weight, an integer value that indicates the processing capacity. Servers with higher weights receive new connections first than those with less weights, and servers with higher weights get more connections than those with less weights and servers with equal weights get equal connections. The pseudo code of weighted round-robin scheduling is as follows:
-In the implementation of the weighted round-robin scheduling, a scheduling sequence will be generated according to the server weights after the rules of Virtual Server are modified. The network connections are directed to the different real servers based on the scheduling sequence in a round-robin manner.
+For example, the real servers, A, B and C, have the weights, 4, 3, 2 respectively, a scheduling sequence will be AABABCABC in a scheduling period (mod sum(Wi)).
 The weighted round-robin scheduling is better than the round-robin scheduling, when the processing capacity of real servers are different. However, it may lead to dynamic load imbalance among the real servers if the load of the requests vary highly. In short, there is the possibility that a majority of requests requiring large responses may be directed to the same real server.

← Older revision		Revision as of 10:35, 20 July 2005
Line 1:		Line 1:
		+	The weighted round-robin scheduling is designed to better handle servers with different processing capacities. Each server can be assigned a weight, an integer value that indicates the processing capacity. Servers with higher weights receive new connections first than those with less weights, and servers with higher weights get more connections than those with less weights and servers with equal weights get equal connections. For example, the real servers, A, B and C, have the weights, 4, 3, 2 respectively, a good scheduling sequence will be AABABCABC in a scheduling period (mod sum(Wi)).
		+
		+	In the implementation of the weighted round-robin scheduling, a scheduling sequence will be generated according to the server weights after the rules of Virtual Server are modified. The network connections are directed to the different real servers based on the scheduling sequence in a round-robin manner.
		+
		+	The weighted round-robin scheduling is better than the round-robin scheduling, when the processing capacity of real servers are different. However, it may lead to dynamic load imbalance among the real servers if the load of the requests vary highly. In short, there is the possibility that a majority of requests requiring large responses may be directed to the same real server.
		+
		+	Actually, the round-robin scheduling is a special instance of the weighted round-robin scheduling, in which all the weights are equal.

	[[Category:Job Scheduling Algorithms]]		[[Category:Job Scheduling Algorithms]]