Native Loopback Accelerator Functional Unit User Guide for Intel® FPGA Programmable Acceleration Card N3000

ID 683693
Date 11/25/2019

1.2. Acronyms

Table 2.  Acronyms
Acronyms Expansion Description
AF Accelerator Function

Compiled Hardware Accelerator image implemented in FPGA logic that accelerates an application.  

AFU Accelerator Functional Unit Hardware Accelerator implemented in FPGA logic which offloads a computational operation for an application from the CPU to improve performance.
API Application Programming Interface A set of subroutine definitions, protocols, and tools for building software applications.
ASE AFU Simulation Environment

Co-simulation environment that allows you to use the same host application and AF in a simulation environment. ASE is part of the Intel® Acceleration Stack for FPGAs.

CCI-P Core Cache Interface CCI-P is the standard interface AFUs use to communicate with the host.
CL Cache Line 64-byte cache line
DFH Device Feature Header Creates a linked list of feature headers to provide an extensible way of adding features.
FIM FPGA Interface Manager

The FPGA hardware containing the FPGA Interface Unit (FIU) and external interfaces for memory, networking, etc.

The Accelerator Function (AF) interfaces with the FIM at run time.

FIU FPGA Interface Unit

FIU is a platform interface layer that acts as a bridge between platform interfaces like PCIe* , UPI and AFU-side interfaces such as CCI-P.

OPAE Open Programmable Acceleration Engine The OPAE is a software framework for managing and accessing AFs.
MPF Memory Properties Factory The MPF is a Basic Building Block (BBB) that AFUs can use to provide CCI-P traffic shaping operations for transactions with the FIU.  
Msg Message Message - a control notification
NLB Native Loopback The NLB performs reads and writes to the CCI-P link to test connectivity and throughput.
RdLine_I Read Line Invalid Memory Read Request, with FPGA cache hint set to invalid. The line is not cached in the FPGA, but may cause FPGA cache pollution.
Note: The cache tag tracks the request status for all outstanding requests on Intel® Ultra Path Interconnect ( Intel® UPI). Therefore, even though RdLine_I is marked invalid upon completion, it consumes the cache tag temporarily to track the request status over UPI. This action may result in the eviction of a cache line, resulting in cache pollution. The advantage of using RdLine_I is that it is not tracked by CPU directory; thus it prevents snooping from CPU.
RdLine-S Read Line Shared

Memory read request with FPGA cache hint set to shared. An attempt is made to keep it in the FPGA cache in a shared state.

WrLine_I Write Line Invalid

Memory Write Request, with FPGA cache hint set to Invalid. The FIU writes the data with no intention of keeping the data in FPGA cache.

WrLine_M Write Line Modified

Memory Write Request, with the FPGA cache hint set to Modified. The FIU writes the data and leaves it in the FPGA cache in a modified state.