Changes between Version 16 and Version 17 of LLM

Timestamp:

10/12/11 23:40:28 (13 years ago)

Author:

lvpeng

Comment:

--

LLM

@@ -47 +47 @@
 [[Image(figure3.jpg)]]
 
-          Figure 3. Downtime under highNet and highsys.
+          Figure 3. Downtime under highnet and highsys.
  
-We observe that under highsys, [wiki:LLM LLM] incurs a downtime that is longer than, yet comparable to, that of [http://nss.cs.ubc.ca/remus/ Remus]. The reason is that, [wiki:LLM LLM] runs at low frequency, hence the migration traffic in each period is higher than that of [http://nss.cs.ubc.ca/remus/ Remus]. Under highnet, the downtime of [wiki:LLM LLM] and [http://nss.cs.ubc.ca/remus/ Remus] show a reverse relationship, where [wiki:LLM LLM] outperforms [http://nss.cs.ubc.ca/remus/ Remus]. This is because, from the client side, there are too many duplicated packets to be served again by the backup machine in [http://nss.cs.ubc.ca/remus/ Remus]. In [wiki:LLM LLM], on the contrary, the primary machine migrates the requested packets as well as boundaries to the backup machine, i.e., only those packets yet to be served are served by the backup. Thus the client does not need to re-transmit the requests, and therefore experiences a shorter downtime.
+We measured the downtime under highnet and highsys, the results of which are shown in Figures 3 and 4. We observe that under highsys, [wiki:LLM LLM] incurs a downtime that is longer than, yet comparable to, that of [http://nss.cs.ubc.ca/remus/ Remus]. The reason is that, [wiki:LLM LLM] runs at low frequency, hence the migration traffic in each period is higher than that of [http://nss.cs.ubc.ca/remus/ Remus]. Under highnet, the downtime of [wiki:LLM LLM] and [http://nss.cs.ubc.ca/remus/ Remus] show a reverse relationship, where [wiki:LLM LLM] outperforms [http://nss.cs.ubc.ca/remus/ Remus]. This is because, from the client side, there are too many duplicated packets to be served again by the backup machine in [http://nss.cs.ubc.ca/remus/ Remus]. In [wiki:LLM LLM], on the contrary, the primary machine migrates the requested packets as well as boundaries to the backup machine, i.e., only those packets yet to be served are served by the backup. Thus the client does not need to re-transmit the requests, and therefore experiences a shorter downtime.
 
 [[Image(figure4.jpg)]]
 
-             Figure 4. Network Delay under highNet and highsys.
+             Figure 4. Network Delay under highnet and highsys.
 
 We evaluated the network delay under highnet and highsys as shown in Figure 4. In both cases, we observe that [wiki:LLM LLM] significantly reduces the network delay by removing the egress queue management and releasing responses immediately. In Figure 4, we only recorded the average network delay in a migration period. Next, we show the details of the network delay in a specific migration period in Figure 4, in which the interval between two adjacent peak values represents one migration period. We observe that the network delay of [http://nss.cs.ubc.ca/remus/ Remus] decreases linearly within a period but remains at a plateau. In [wiki:LLM LLM], on the contrary, the network delay is very high at the beginning of a period, then quickly decreases to nearly zero after a system update is over. Therefore, most of the time, [wiki:LLM LLM] demonstrates a much shorter network delay than [http://nss.cs.ubc.ca/remus/ Remus].