crude little benchmark for parallelizing bundle-installed gems

bundlemark.sh

#!/bin/bash

TMPDIR="$(mktemp -d)"
CORES=$(sysctl -n hw.ncpu 2>/dev/null || nproc)
echo "==> testing with $CORES cores in $TMPDIR"
cd $TMPDIR

RUBY_VERSION=$(rbenv version-name)
TIME=$(which time)

function run {
  export MAKEFLAGS="-j$1"
  export BUNDLE_JOBS="$2"
  export GEMSET="gems_${RUBY_VERSION}_make${MAKEFLAGS}_bundle-jobs-${BUNDLE_JOBS}" 
  echo "==> installing Rails for $GEMSET"
  echo "./${GEMSET} global" >.ruby-gemset
  $TIME ruby -r bundler/inline -e 'gemfile { source "https://rubygems.org"; gem "rails", "6.0.0.rc1" }'
}

run 1 1
run 1 $CORES
run $CORES 1
run $CORES $CORES

echo '==> cleaning up'
rm -rf "$TMPDIR"