Cisco ExaNIC Software

For low-latency applications, you can accelerate standard Linux socket applications using the exasock wrapper. This wrapper hooks socket calls and sends data directly to the card, bypassing the kernel without requiring application recompilation.

Additionally, exasock provides an extensions API for a hybrid model: using standard sockets for most TCP functions while bypassing the kernel on the critical path for performance.

The Exasock.ko kernel module has been extended to support network bonding, but it is subject to the following constraints:

• Mode Support: It only supports active-backup mode.
• Device Compatibility: It is designed to manage bonds containing ExaNIC devices.
• Exclusivity: The module will reject attempts to:
  • Bind to existing bonding interfaces that contain non-ExaNIC devices.
  • Add a non-ExaNIC device to a bond that is currently under Exasock.ko management.

To install the ExaNIC drivers, utilities, and libraries from source, build the project using make and then install it using sudo make install from the repository root.

For full installation instructions and a comprehensive user guide, refer to the ExaNIC User Guide.

The exanic-measure application is used to benchmark external devices with high precision using ExaNIC HPT (or other devices like ExaNIC X10/X25/X40/X100). To achieve high precision, follow this two-step calibration process to compensate for cabling and internal NIC delays:

1. Calibration: Measure a device with zero latency (e.g., an optical coupler). Note the "average" number reported; this represents your calibration offset.
2. Measurement: Replace the coupler with the target device (using the same cables). Run the application again using the -O parameter with the offset value obtained in step 1.

This process ensures the result is compensated for cabling delays and internal NIC delays.

# Example usage pattern for calibration
# Step 1: Measure zero-latency device
./exanic-measure

# Step 2: Measure target device with offset
./exanic-measure -O <OFFSET_FROM_STEP_1>

The exanic-benchmarker-stac-t0 application implements the STAC_T0 latency test as defined by the Securities Technology Analysis Center. It works with the stac_t0 FDK example.

Workflow:

1. The application generates UDP datagrams containing random indexes.
2. It expects echoed indexes to return in TCP segments from the stack under test (e.g., an ExaNIC).
3. Hardware timestamps are utilized to calculate the precise latency within the stack.

The ate-connect.c example demonstrates how to use the ExaNIC Accelerated TCP Engine (ATE) to accelerate TCP connections. The program creates a socket, enables ATE for that socket, and connects to a TCP server. Once connected, ATE is capable of sending TCP segments directly from hardware when triggered. The program continuously receives and prints data sent from the server.

Requirement: You must run this program using the exasock wrapper to enable and control the Accelerated TCP Engine. Running it directly will fail.

exasock ./ate-connect 192.168.1.10 11111

The multicast-echo.c example receives multicast UDP packets and echoes them out via a different unicast UDP socket.

To run this with Exasock socket acceleration, use the exasock wrapper.

Constraints:

• The source address (e.g., 192.168.1.11) must be the address of an ExaNIC interface.
• The route to the destination address (e.g., 192.168.2.10) must go out via an ExaNIC interface.

exasock ./multicast-echo 224.1.2.3:192.168.1.11:14159 192.168.2.10:26535

The tcp-raw-send.c example demonstrates the Exasock extensions API. It allows you to retrieve a raw TCP header from an accelerated socket, manually construct a TCP segment, and send it using the raw API (libexanic).

This API is useful for performing TCP transmission from outside standard sockets, such as from the ExaNIC FPGA or by preloading transmit buffers on the card.

Requirement: You must run this program using the exasock wrapper. If run without it, the extensions API function stubs will not be replaced by the preloaded Exasock versions, and the program will fail.

exasock ./tcp-raw-send 192.168.1.11 11111