Intel Ethernet Cloud White Paper

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Each generation of processors delivers
dramatic compute-performance
improvements over what came
before, and this has driven the use of
virtualization to maximize the efcient
use of that compute. To maintain a
balanced compute environment in a
virtualized environment, it is therefore
necessary to provide very high levels
of network I/O throughput and
performance VMs.
10GbE provides the means to increase
raw bandwidth, but to use the effective
bandwidth across the VMs, optimizations
are required in the virtualized
environment. Intel® Virtualization for
Connectivity (Intel® VT-c) provides these
virtualization capabilities in the Intel
Ethernet silicon. Intel VT-c transitions
physical network models traditionally used
in data centers to more efcient models
by providing port partitioning, multiple
Rx/Tx queues, and on-controller QoS
functionality that can be used in virtual
server deployments. These functions
help reduce I/O bottlenecks and improve
overall server performance by ofoading
the data sorting and queuing functionality
to the Intel Ethernet controller.
Intel VT-c provides native balanced
bandwidth allocation and optimized I/O
scalability. These functions help reduce
I/O bottlenecks and help improve overall
server performance by accelerating
functionality in the Ethernet controller,
as shown in Figure 3. That acceleration
reduces the data processing bottleneck
associated with virtualization by providing
queue separation for each VM and
intelligently ofoading switching and
sorting operations from the hypervisor
to the server adapter hardware.
To improve hypervisor performance,
Intel VT-c supports separate queuing for
individual VMs on the network controller
itself, by relieving it of the burden of
sorting incoming network I/O data, as
well as improving fairness among VMs.
This capability provides multiple network
queues and a hardware-based sorter/
classier built into the network controller,
providing optimized I/O performance as well
as add-on capabilities such as a rewall.
Intel VT-c enables a single Ethernet port
to appear as multiple adapters to VMs.
Each VM’s device buffer is assigned a
transmit/receive queue pair in the Intel
Ethernet controller, and this pairing
between VM and network hardware helps
avoid needless packet copies and route
lookups in the hypervisor’s virtual switch.
The result is less data for the hypervisor
to process and an overall improvement in
I/O performance.
Intel VT-c includes Virtual Machine Device
Queues (VMDq)
2
and Single Root I/O
Virtualization (SR-IOV) support (please
refer to the sidebars in this document
for details on these technologies). Both
enable dynamic allocation of bandwidth
for optimal efciency in various trafc
conditions and are engineered specically
to provide optimal exibility in migration
as well as elasticity of bandwidth.
Proprietary hardware, on the other hand,
takes the approach of splitting up the
10GbE bandwidth by advertising separate
functions for virtual connections. This
method inherently limits the virtual ports
to a small number of connections and fails
to address the elasticity needs of the
network by prescribing a static bandwidth
allocation per port.
Server 1Server n
Management
Virtual Switch
Console
Aggregation
10GbE Switch
Separate servers are replaced by VMs
on one physical host
Aggregation
GbE Switch
Hypervisor
Physical Host 1
Aggregation 10GbE,
FCoE Switch
iSCSI, Fibre
Channel SAN
with 10GbE
Storage Processor
VM nVM 1
LAN
Virtual Switch
Storage
Initiators
Intel® VT-c
GbE
LOM
Virtual Switches Replace
Top-of-Rack Switches
Redundant Data Storage Connectivity
10GbE
Server
Adapter
Intel® VT-c
10GbE
Server
Adapter
WAN
g
at
i
o
n
gation
A
G
bE
,
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Intel® Virtualization for Connectivity offloads switching and sorting from the processor
to the network silicon, for optimized performance.
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