scripts/parallel-nextpnr-nexus

#!/bin/bash
# Copyright 2022 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Runs multiple nextpnrs, stopping on the first successful run

# TODO: Better argument handling
# TODO: Include support for device, timefailarg and ignoreloops parameters
# TODO: Include support for setting seed (or baseseed in this case)
if [[ $# -ne 5 ]]; then
  echo "Expected 5 arguments"
  exit 255
fi

name="$(basename "$0")"
JSON="$1"
PDC="$2"
RESULT_FASM="$3"
SEED_COUNT="$4"
SEED_BASE="$5"


### Only bash 5.1 and later have "wait -p"
if ! wait -p ZZZ; then
    echo "${name}: ERROR this version of bash (${BASH_VERSION}) does not have"
    echo "required feature wait -p."
    exit 1
fi

# A standard array containing all child process ids
declare -a CHILD_PIDS

# Associative array mapping child process to seed used to start it
declare -A PID_TO_SEED

# This lets us detect a nextpnr-nexus failure in the pipelines spawned below
set -o pipefail

# Launch a number of nextpnrs
echo "${name}: running ${SEED_COUNT} nextpnr-nexus instances."
rm -rf runs
mkdir runs
for s in $(seq 0 $(("${SEED_COUNT}"-1))); do
  seed=$(("${SEED_BASE}" + s))
  DIR="runs/seed-${seed}"
  mkdir "${DIR}"
  (
    nextpnr-nexus \
        --json "${JSON}" \
        --pdc "${PDC}" \
        --fasm "${DIR}/output.fasm" \
        --device LIFCL-17-8UWG72C \
        --report="${DIR}/report.json" \
        --detailed-timing-report \
        --placer-heap-timingweight 50 \
        --estimate-delay-mult 25 \
        --seed "${seed}" 2>&1 | \
      (while read -r line; do
        echo "$(date +%H:%M:%S) ${line}"; done
      ) > "${DIR}/nextpnr-nexus.log"
  ) &
  PID=$!
  # Record process ID
  CHILD_PIDS+=("${PID}")
  echo "Launched nextpnr with output to ${DIR}"
  # Record mapping to seed
  PID_TO_SEED[${PID}]="${seed}"
done


# While there are still running children
while [[ ${#CHILD_PIDS} -gt 1 ]]; do
  # Wait for a child to finish then check for success or failure
  wait -n -p TERMINATED "${CHILD_PIDS[@]}"
  result=$?

  # Remove finished child from list
  new_CHILD_PIDS=()
  for p in "${CHILD_PIDS[@]}"; do
    # shellcheck disable=SC2154  # TERMINATED assigned above by wait -p
    if [[ "${p}" -ne "${TERMINATED}" ]]; then
      new_CHILD_PIDS+=("${p}")
    fi
  done
  CHILD_PIDS=("${new_CHILD_PIDS[@]}")

  # Take action depending on success or failure
  if [[ "${result}" -eq "0" ]]; then
    # Child succeeded - copy result and finish
    seed="${PID_TO_SEED[${TERMINATED}]}"
    echo "SUCCESS: nextpnr with seed=${seed}"
    cp "runs/seed-${seed}/output.fasm" "${RESULT_FASM}"
    cp "runs/seed-${seed}/nextpnr-nexus.log" nextpnr-nexus.log
    cp "runs/seed-${seed}/report.json" report.json
    # TODO: find a more elegant solution for halting all children
    for p in "${CHILD_PIDS[@]}"; do pkill -P "${p}"; done
    exit 0
  else
    # Child failed - output a message and continue
    seed="${PID_TO_SEED[${TERMINATED}]}"
    echo "FAIL: nextpnr with seed=${seed}"
  fi
done

# No success found
echo "All seeds failed"
exit 1