Read this Quickstart if you are migrating to the X3522 adapter from its predecessors that were designed by Solarflare, such as the 7000-series, 8000-series and XtremeScale X2-series. It outlines the major differences between the X3522 and its predecessors, and where to find out more:
Reduced Latency
- ½ RTT latency for an X3522 is about 230 ns lower than for an X2522, measured using eflatency with a 200 byte packet over PCIe® Gen4 and 10 GbE.
- The X3522 has been optimized for PCIe Gen4. Using PCIe Gen3 instead of Gen4 incurs a ½ RTT penalty of >80 ns.
See the Onload User Guide (UG1586) for full details of test setup, and for comprehensive latency values and graphs.
New RX and TX Data Path Designs
- RX queues are managed by the driver and are shared between applications. Applications that share a queue should run on cores that share their L3 cache. Explicit huge pages are required.
- TX always uses CTPIO, with 16 apertures per port instead of the single aperture used by the X2-series, allowing senders to have a dedicated aperture. This and other design improvements have made CTPIO more robust.
See Queue Handling, Receive, and Transmit.
New Drivers and Software Packages
- The X3522 uses a new Linux net driver
named
xilinx_efct, supplied separately from Onload. - The X3522 also uses the auxiliary bus driver. This is provided by some recent Linux distributions, or can be downloaded from AMD.
- If you are using Onload you must build these new drivers first, before you build Onload. Likewise, you must load these drivers before you load Onload.
- TCPDirect is now supplied in its own package, separately from Onload.
See the Alveo X3522 Installation Guide (UG1522), the Onload User Guide (UG1586) and the TCPDirect User Guide (SF-116303-CD).
Low Background Traffic Recommended
- The kernel stack is not performant, and is only intended for light background traffic.
- If any applications generate high traffic, consider accelerating them with Onload.
- IGMP snooping is strongly recommended.
See the Onload User Guide (UG1586) to accelerate applications.
Focused Feature Set
- Some features not normally used in low latency deployments because of their adverse impact are removed.
- The maximum MTU is 1500 bytes.
See Features.
Standardized Tools for Firmware Management
- The
sfupdateandsfbootutilities are no longer used. - The
devlinkorethtoolLinux utilities are instead used for update, configuration, and information.
Higher Power Requirement
- Power draw varies more with traffic load.
- The X3522 uses more power than the X2-series.
- Its airflow requirements are consequently higher.
See the Alveo X3522 Data Sheet (DS1002).
DSFP28 Cages
- The X3522 has two DSFP28 cages, each of which supports two ports.
- If you connect a DSFP28 cable, or a DSFP28 to SFP splitter, both ports for the cage are exposed.
- If you connect an SFP cable, only the first port for the cage is exposed.