Christopher Celio 2014 Sep 1

This is a trace-based simulator designed to explore branch prediction strategies.

In particular, BTB, BHT, and RAS interations with superscalar fetch units.

Getting Started

replay mode

./pythia -t vvadd

live mode

./pythia -s ../riscv-tools/riscv-tests/benchmarks/vvadd.riscv

Live mode assumes "lspike" is installed.

For more information:

./pythia -h

There are two modes - "live" mode and "replay" mode.

"Live" mode - is the default mode that invokes "lspike" and pipes the commit log to Pythia. use "-s" to specify the benchmark and its arguments.

"Replay" mode - use "-t" to name a tracefile in the "traces" directory to replay a run.

Setting Up

"Live" mode will require the riscv-tools to be installed. In particular, it needs to make use of the "commit logging" ability of "spike".

1. Modify riscv-tool's "build.sh" to compile the "spike" ISA simulator into a new directory.

build_project riscv-fesvr --prefix=$RISCV/logger
build_project riscv-isa-sim --prefix=$RISCV/logger --with-fesvr=$RISCV/logger --enable-commitlog 

2. Rename $RISCV/logger/bin/spike to $RISCV/logger/bin/lspike.

3. Finally, add $RISCV/logger/bin to your bash environment path.