Solarflare
Server
Adapter
User
Guide
Solarflare
Adapters
on
Windows
Issue
20
©
Solarflare
Communications
2017
238
Intel®
QuickData
/
NetDMA
On
systems
that
support
Intel
I/OAT
(I/O
Acceleration
Technology)
features
such
as
QuickData
(a.k.a
NetDMA),
Solarflare
recommend
that
these
are
enabled
as
they
are
rarely
detrimental
to
performance.
Using
Intel®
QuickData
Technology
allows
data
copies
to
be
performed
by
the
system
and
not
the
operating
system.
This
enables
data
to
move
more
efficiently
through
the
server
and
provide
fast,
scalable,
and
reliable
throughput.
To
enable
NetDMA
the
EnableTCPA
variable
must
be
set
to
1
in
the
Tcpip\Parameters
registry
key.
Locate
the
following
key
in
the
registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
The
EnableTCPA
value
must
be
created
if
it
is
not
present
and
set
to
1:
EnableTCPA
=
1
Intel
Hyper
‐
Threading
Technology
On
systems
that
support
Intel
Hyper
‐
Threading
Technology
users
should
consider
benchmarking
or
application
performance
data
when
deciding
whether
to
adopt
hyper
‐
threading
on
a
particular
system
and
for
a
particular
application.
Solarflare
have
identified
that
hyper
‐
threading
is
generally
beneficial
on
systems
fitted
with
Core
i5,
Core
i7
and
Xeon
(Nehalem
or
later)
CPUs.
TCP/IP
Options
TCP
timestamps,
window
scaling
and
selective
acknowledgments
are
enabled
by
default
on
supported
platforms,
and
include
receive
window
tuning
and
congestion
control
algorithms
that
automatically
adapt
to
10
gigabit
connections.
There
is
therefore
no
need
to
change
these
settings.
Power
Saving
Mode
Modern
processors
utilize
design
features
that
enable
a
CPU
core
to
drop
into
low
power
states
when
instructed
by
the
operating
system
that
the
CPU
core
is
idle.
When
the
OS
schedules
work
on
the
idle
CPU
core
(or
when
other
CPU
cores
or
devices
need
to
access
data
currently
in
the
idle
CPU
core’s
data
cache)
the
CPU
core
is
signaled
to
return
to
the
fully
on
power
state.
These
changes
in
CPU
core
power
states
create
additional
network
latency
and
jitter.
Solarflare
recommend
to
achieve
the
lowest
latency
and
lowest
jitter
that
the
“C1E
power
state”
or
“CPU
power
saving
mode”
is
disabled
within
the
system
BIOS.
In
general
the
user
should
examine
the
system
BIOS
settings
and
identify
settings
that
favor
performance
over
power
saving.
In
particular
look
for
settings
to
disable:
•
C
states
/
Processor
sleep/idle
states
•
Enhanced
C1
CPU
sleep
state
(C1E)
•
Any
deeper
C
states
(C3
through
to
C6)
•
P
states
/
Processor
throttling