Intel 7400 - Manual (Page 9)

Scenarios 2 and 3: Virtualized with
and without VMDq/NetQueue
In these scenarios, the setup shown in Figure 11, consists of
eight clients connected to eight 1-GbE ports of a 1G/10G link
aggregation switch (Force 10 S50) and the Intel Xeon processor
7300 server connected to 10G port of the switch via Intel
82598 10GbE CX4 NIC. On the server, ESX 3.5 is installed and
there are eight virtual machines created. The virtual machines
are configured with 1vCPU; 1 GB RAM and SLES 10 SP1 is the
guest operating system. VMDq with 16 queues along with
NetQueue is enabled on the ESX server, and we are letting
the VMM handle the VMDq assignments, core assignments, and
interrupt affinity. On the clients, SLES 10 SP1 is the operating
system. There are eight parallel streams of UDP latency tests
being run from eight clients to eight virtual machines.
As mentioned earlier, in all the scenarios we used Netperf 2.4.4
UDP latency test and we ran the tests for UDP packet sizes of
64 bytes, 256 bytes, and 1024 bytes. The ESL workload used
UDP packets of sizes varying from 40 to 200 bytes.
The results from these tests are summarized in Figure 12. In
the graph, we are comparing native, virtualized with VMDq, and
virtualized with no VMDq (represented by the blue, light blue, and
gray bars, respectively). The horizontal axis represents various
UDP packet sizes in bytes, and the vertical axis represents the
average latency in milliseconds.
From Figure 12 it can be concluded that virtualization increases
the latency. In fact, the latency is doubled (for 64-byte packets,
the latency in the native scenario is 0.12 ms, whereas in the
virtual ized scenario with no VMDq it is 0.24 ms). By enabling VMDq
and NetQueue, the latency in the virtualized case is near native
(~0.13 ms). The increase in latency by virtualizing has a negligible
impact when compared to in-game latency of 5 ms best case.
Figure 11 . Virtualized lab test setup .
10 GbE
ESX* Server
Force 10 S50*
Client 1
1 GbE
Client 8
1 GbE
VM1
VM8
vSW1
64
0.30
0.25
0.20
0.15
0.10 Av
er
age la
tency (rms
)
256 1024
Packet size (bytes)
0.05
No VMDq VMDq Native
Figure 12 . Netperf 2 .4 .4 UDP latency test with eight
parallel streams .
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