<s>
In	O
virtualization	B-General_Concept
,	O
single	O
root	O
input/output	O
virtualization	B-General_Concept
(	O
SR-IOV	B-Protocol
)	O
is	O
a	O
specification	O
that	O
allows	O
the	O
isolation	O
of	O
PCI	O
Express	O
resources	O
for	O
manageability	O
and	O
performance	O
reasons	O
.	O
</s>
<s>
A	O
single	O
physical	O
PCI	O
Express	O
bus	O
can	O
be	O
shared	O
in	O
a	O
virtual	O
environment	O
using	O
the	O
SR-IOV	B-Protocol
specification	O
.	O
</s>
<s>
The	O
SR-IOV	B-Protocol
offers	O
different	O
virtual	B-Architecture
functions	I-Architecture
to	O
different	O
virtual	O
components	O
(	O
e.g.	O
</s>
<s>
network	B-Protocol
adapter	I-Protocol
)	O
on	O
a	O
physical	O
server	O
machine	O
.	O
</s>
<s>
SR-IOV	B-Protocol
uses	O
physical	O
and	O
virtual	B-Architecture
functions	I-Architecture
to	O
control	O
or	O
configure	O
PCIe	O
devices	O
.	O
</s>
<s>
Physical	O
functions	O
have	O
the	O
ability	O
to	O
move	O
data	O
in	O
and	O
out	O
of	O
the	O
device	O
while	O
virtual	B-Architecture
functions	I-Architecture
are	O
lightweight	O
PCIe	O
functions	O
that	O
support	O
data	O
flowing	O
but	O
also	O
have	O
a	O
restricted	O
set	O
of	O
configuration	O
resources	O
.	O
</s>
<s>
The	O
virtual	O
or	O
physical	O
functions	O
available	O
to	O
the	O
hypervisor	B-Operating_System
or	O
guest	O
operating	O
system	O
depend	O
on	O
the	O
PCIe	O
device	O
.	O
</s>
<s>
The	O
SR-IOV	B-Protocol
allows	O
different	O
virtual	B-Architecture
machines	I-Architecture
(	O
VMs	O
)	O
in	O
a	O
virtual	O
environment	O
to	O
share	O
a	O
single	O
PCI	O
Express	O
hardware	O
interface	O
.	O
</s>
<s>
A	O
major	O
field	O
of	O
application	O
for	O
SR-IOV	B-Protocol
is	O
within	O
the	O
high-performance	B-Architecture
computing	I-Architecture
(	O
HPC	O
)	O
field	O
.	O
</s>
<s>
The	O
use	O
of	O
high-performance	O
InfiniBand	B-Architecture
networking	O
cards	O
is	O
growing	O
within	O
the	O
HPC	O
sector	O
,	O
and	O
there	O
is	O
early	O
research	O
into	O
the	O
use	O
of	O
SR-IOV	B-Protocol
to	O
allow	O
for	O
the	O
use	O
of	O
InfiniBand	B-Architecture
within	O
virtual	B-Architecture
machines	I-Architecture
such	O
as	O
Xen	B-Operating_System
.	O
</s>
