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Latency
The next series of tests aimed at quantifying average latency deltas between 10GbE and 25GbE. The same
four workloads were run across the same four configurations. See below for comparison examples:
Figure 4: Latency averages for DVDStore operations. We see that 25GbE is at parity or notably
improves latency across the 10GbE VM workloads.
Figure 5: Latency averages for Webserver operations. At 12 and 16VM’s the 10GbE adapter runs
much slower than 25GbE.
Latency overall followed the same pattern, with speed loss occurring once more than 8 VM’s were added to the
10GbE tests. All 10GbE workloads running 12 or more VMs had higher latencies than the latency for the 16VM
25GbE workload. At 16 VMs each, we see a 25% overall reduction in latency on the 25GbE adapter.
About now the general trend has become obvious – so long as the 10GbE VM workload is roughly greater than
half of the 25GbE workload, it becomes advantageous to use the higher capacity adapter. This does seem to
be the case, but before drawing final conclusions there are a few more pools of data to analyze: