NOVIA

NOVIA: A Framework for Discovering Non-Conventional Inline Accelerators, is an LLVM-based toolset that allows for automatic recognition, instantiation and code instrumentations of inline accelerators. NOVIA uses unified bitcode files to analyze a workload and propose inline accelerators to the architect.

The current NOVIA release does not provide the hardware support [NOVIA Functional Unit (NFU)] or the compiler support (clang patch) to compile NFU instructions to RISC-V. Future commits will provide those (Published in novia 1.5.0 branch with limited functionality).

https://dl.acm.org/doi/abs/10.1145/3466752.3480094

Publication

If you use NOVIA you can cite us:

@inbook{10.1145/3466752.3480094,
author = {Trilla, David and Wellman, John-David and Buyuktosunoglu, Alper and Bose, Pradip},
title = {NOVIA: A Framework for Discovering Non-Conventional Inline Accelerators},
year = {2021},
isbn = {9781450385572},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/3466752.3480094},
booktitle = {MICRO-54: 54th Annual IEEE/ACM International Symposium on Microarchitecture},
pages = {507–521},
numpages = {15}
}

Install

Dependencies

• cmake ninja-build gcc g++ (for build)
• libgd-dev qt4-qmake libqt4-dev autoconf automake libtool bison flex (for Graphviz)
• python3 python3-pandas python3-termcolor (for automated scripts)

Automatically installed dependencies

• llvm 13.0.0 (https://github.com/llvm/llvm-project/tree/llvmorg-13.0.0)
• graphviz commit 93d330be (https://gitlab.com/graphviz/graphviz/-/commit/93d330be85c25a5f0b0c86e73f40b4f8d7a42264out)

Native

This requires the dependencies mentioned in the previous section, and will install the automated dependencies.

cd ./scripts/ && ./install.sh

Docker Install

docker build . -t novia:v1

Docker Run

docker run -it novia:v1 /bin/bash

Getting Started

NOVIA comes with several automated examples in the subdirectory fusion/examples. The examples contain the base source code, a makefile that generates the input bitcode for novia and a configuration file needed for novia to compile bitcode (mainly the libraries and linking flags needed).

0. source env.sh
1. cd fusion/examples/incremental
2. make
3. novia incremental.bc

Type novia -h for additional help.

Usage Instructions

0. source env.sh before usage.
1. Generate a unified LLVM IR bitcode file of the binary to analyze:
   1. Use clang and -emit-llvm flag to generate bitcode files
   2. Use llvm-link to merge several bitcode fites into a unified bitcode file
2. Apply methodology:
   1. Generate a configuration file with two variables $EXECARGS (Execution arguments that will be used when profiling the workload) $LDFLAGS (Linking flags and libraries needed to compile the workload). You can find examples of that in the example directory (e.g., fusion/examples/incremental/conf.sh)
   2. Run the novia tool ( novia *bitcode_file* ) [source env.sh or use the full path to the tool in fusion/bin]
   3. The tool will generate a novia folder containing the intermediatte bitcode files of the analysis

Directory Structure

• fusion: novia related scripts and files
  • fusion/examples: synthetically crafted examples
  • fusion/analysis/scripts: data treatment scripts
  • fusion/src: source code
  • fusion/bin: link to novia executable script
• scripts: installation scripts

Generated Files

When the novia automated analysis script is executed on a bitcode file, the following directories and files will be generated in the bitcode's directory:

• novia folder:
  • copy of original analyzed bitcode file
  • executable binary of instrumented bitcode file
  • novia/output: annotated bitcode and configuration file for the SoC/Accelerator integration
  • novia/bitcode: folder with intermediate optimized bitcode files
  • novia/data: raw data files for analysis and output summaries:
    • bblist.txt: List of basic blocks analyzed by the tool
    • histogram.txt: Profiling data per basic block:
      • data fields-[cycle count,total application cycle count,iterations]
    • weights.txt: Derived data analysis from histogram.txt:
      • data fields-[time % of bitcode,time % of entire application,iterations]
    • orig.csv/merge.csv/split.csv: Data metrics for different novia stages
    • io_overhead.csv: Metrics refering to input and output variables for the accelerators
    • stats.csv: Other metrics
    • source.log: Location in source code of basic blocks and accelerators
  • novia/imgs: DFGs of the analyzed basic blocks, merged ISs and final accelerator candidates in .png format