#!/usr/bin/env bash

# https://cirosantilli.com/linux-kernel-module-cheat#gem5-run-benchmark

set -eu
root_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null && pwd)"
outfile="${root_dir}/out/gem5-bench-dhrystone.txt"
arch=aarch64
cmd="./run --arch '$arch' --emulator gem5 --eval-after './gem5.sh'"

# These cache sizes roughly match the ARM Cortex A75
# https://en.wikipedia.org/wiki/ARM_Cortex-A75
restore='--gem5-restore 1 -- --cpu-type=HPI --restore-with-cpu=HPI --caches --l2cache --l1d_size=64kB --l1i_size=64kB --l2_size=256kB'

# Generate a checkpoint after Linux boots, using the faster and less detailed CPU.
# The boot takes a while, be patient young Padawan.
eval "$cmd"

printf 'n cycles\n' > "$outfile"
for n in 1000 10000 100000; do
  # Restore the most recent checkpoint taken with the more detailed and slower HPI CPU,
  # and run the benchmark with different parameters. We skip the boot completely, saving time!
  eval "${cmd} --gem5-readfile 'm5 resetstats;dhrystone ${n};m5 dumpstats' ${restore}" &>/dev/null
  printf "${n} " >> "$outfile"
  ./gem5-stat --arch "$arch" | head -n 1 >> "$outfile"
done