Solarflare Solarflare XtremeScale series, User Manual, Page: 243 / 400

Solarflare Server Adapter User Guide
Solarflare Adapters on Windows
Issue 20 © Solarflare Communications 2017 236
Likewise, for low latency low jitter applications, the network application should be
run on NUMA nodes that are local to the interface:
• The application can set affinity itself with
SetProcessAffinityMask
and
SetThreadAffinityMask
, and then may present these as options to the user.
• Affinity can be set using Sysinternals Process Explorer (
procexp
). Right click on
the process and choose Set Affinity .
• Affinity can be controlled when a process is started using:
START /AFFINITY <hexmaskl> <command>
or
START /NODE <num> <command>
When
/NODE
and
/AFFINITY
are used together, affinity is interpreted as cores
within the node.
For other applications, such as web servers:
• On Windows Server 2012 and later, use one of the following RSS profiles:
‐ NumaScaling
‐ NumaScalingStatic
The PowerShell
Get ‐ NetAdapterRss
cmdlet will give this information.
The RSS Profile can be set in the Network Adapter's Advanced Properties Page,
or with the PowerShell cmdlet
Set ‐ NetAdapterRss
Other Considerations
PCI Express Lane Configurations
The PCI Express (PCIe) interface used to connect the adapter to the server can
function at different speeds and widths. This is independent of the physical slot size
used to connect the adapter. The possible widths are multiples x1, x2, x4, x8 and x16
lanes of (2.5Gbps for PCIe Gen 1, 5.0 Gbps for PCIe Gen 2 and 8.0Gbps for PCIe Gen
3) in each direction. Solarflare adapters are designed for x8 or x16 lane operation .
On some server motherboards, choice of PCIe slot is important. This is because
some slots (including those that are physically x8 or x16 lanes) may only electrically
support x4 lanes. In x4 lane slots, Solarflare PCIe adapters will continue to operate,
but not at full speed. The Solarflare driver will insert a warning in the Windows
Event Log if it detects that the adapter is plugged into a PCIe slot which electrically
has fewer than x8 lanes.
Solarflare SFN5000 and SFN6000 series adapters require a PCIe Gen 2 x8 slot for
optimal operation. Solarflare SFN7000 and SFN8000 series adapters require a PCIe
Gen 3 x8 or x16 slot for optimal performance. The Solarflare driver will insert a
warning in the Windows Event Log if it detects that the adapter is placed in a sub ‐
optimal slot.