Add script to run Adler-32 and CRC-32 benchmarks

tools/checksum_benchmarks.sh

@@ -0,0 +1,73 @@
+#!/bin/bash
+
+set -eu
+
+if [ $# -eq 0 ]; then
+	FILE="$HOME/data/silesia"
+	echo "Using default FILE: $FILE"
+	echo
+elif [ $# -eq 1 ]; then
+	FILE="$1"
+else
+	echo "Usage: $0 [FILE]" 1>&2
+	exit 1
+fi
+
+
+if ! grep -q '\<sse2\>' /proc/cpuinfo; then
+	echo "This script must be run on an x86 CPU" 1>&2
+	exit 1
+fi
+
+if [ -n "$(git status -s | egrep 'adler32.c|crc32.c')" ]; then
+	echo "This script will overwrite adler32.c and crc32.c, which" \
+		"have uncommitted changes.  Refusing to run." 1>&2
+	exit 1
+fi
+
+do_benchmark() {
+	method="$1"
+	shift
+	speed=$(./checksum "$@" -t "$FILE" | \
+		grep -o '[0-9]\+ MB/s' | grep -o '[0-9]\+')
+	printf "%-36s%-10s\n" "$method" "$speed"
+}
+
+sort_by_speed() {
+	awk '{print $NF, $0}' | sort -nr | cut -f2- -d' '
+}
+
+cat << EOF
+Method                              Speed (MB/s)
+------                              ------------
+EOF
+
+# CRC-32
+(
+if grep -q '\<pclmulqdq\>' /proc/cpuinfo; then
+	make checksum > /dev/null
+	do_benchmark "CRC-32 (libdeflate, PCLMUL)"
+fi
+sed -i '/^#if defined(__PCLMUL__)/,/^\#endif$/d' lib/crc32.c
+make checksum > /dev/null
+do_benchmark "CRC-32 (libdeflate, generic)"
+git checkout -f lib/crc32.c > /dev/null
+do_benchmark "CRC-32 (zlib)" -Z
+) | sort_by_speed
+
+# Adler-32
+echo
+(
+if grep -q '\<avx2\>' /proc/cpuinfo; then
+	make checksum > /dev/null
+	do_benchmark "Adler-32 (libdeflate, AVX2)" -A
+fi
+sed -i '/^#if defined(__AVX2__)/,/^\#endif$/d' lib/adler32.c
+make checksum > /dev/null
+do_benchmark "Adler-32 (libdeflate, SSE2)" -A
+sed -i '/^#ifdef __SSE2__/,/^\#endif$/d' lib/adler32.c
+make checksum > /dev/null
+do_benchmark "Adler-32 (libdeflate, generic)" -A
+git checkout -f lib/adler32.c > /dev/null
+do_benchmark "Adler-32 (zlib)" -A -Z
+) | sort_by_speed