contrib/revsetbenchmarks.sh

contrib: don't hardcode path to bash interpreter

Use the env binary to figure out the correct bash to use.
Certain systems ships with an ancient version of bash, but the
user might have installed a newer one that is earlier in $PATH.

For example the current version of Mac OS X ships version 3.2.51
of bash, which does not understand new fancy builtins such as
readarray. A user might install a newer version of bash, use that
as their shell and add that path before bin.

#!/usr/bin/env bash

# Measure the performance of a list of revsets against multiple revisions
# defined by parameter. Checkout one by one and run perfrevset with every
# revset in the list to benchmark its performance.
#
# - First argument is a revset of mercurial own repo to runs against.
# - Second argument is the file from which the revset array will be taken
#   If second argument is omitted read it from standard input
#
# You should run this from the root of your mercurial repository.
#
# This script also does one run of the current version of mercurial installed
# to compare performance.

HG="hg update"
PERF="./hg --config extensions.perf=contrib/perf.py perfrevset"
BASE_PERF="hg --config extensions.perf=contrib/perf.py perfrevset"

TARGETS=$1
shift
# read from a file or from standard output
if [ $# -ne 0 ]; then
    readarray REVSETS < $1
else
    readarray REVSETS
fi

hg update --quiet

echo "Starting time benchmarking"
echo

echo "Revsets to benchmark"
echo "----------------------------"

for (( j = 0; j < ${#REVSETS[@]}; j++ ));
do
  echo "${j}) ${REVSETS[$j]}"
done

echo "----------------------------"
echo

# Benchmark baseline
echo "Benchmarking baseline"

for (( j = 0; j < ${#REVSETS[@]}; j++ ));
  do
    echo -n "${j}) "
    $BASE_PERF "${REVSETS[$j]}"
done

echo
echo

# Benchmark revisions
for i in $(hg log --template='{rev}\n' --rev $TARGETS);
do
  echo "----------------------------"
  echo -n "Revision: "
  hg log -r $i --template "{desc|firstline}"

  echo "----------------------------"
  $HG $i
  for (( j = 0; j < ${#REVSETS[@]}; j++ ));
  do
    echo -n "${j}) "
    $PERF "${REVSETS[$j]}"
  done
  echo "----------------------------"
done

$HG

# Benchmark current code
echo "Benchmarking current code"

for (( j = 0; j < ${#REVSETS[@]}; j++ ));
  do
    echo -n "${j}) "
    $PERF "${REVSETS[$j]}"
done


echo
echo "Time benchmarking finished"