Simple performance benchmark script

perf.sh

@@ -0,0 +1,98 @@
+#! /bin/sh
+
+set -e
+
+create_src() {
+    n=$1
+    i=0
+    while [ $i -lt $n ]; do
+        file=$i.cc
+        cat <<EOF >$file
+#include <algorithm>
+#include <deque>
+#include <iostream>
+#include <list>
+#include <map>
+#include <set>
+#include <sstream>
+#include <string>
+#include <vector>
+int var$i;
+EOF
+        i=$(($i + 1))
+    done
+}
+
+compile() {
+    n=$1
+    compiler=$2
+    i=0
+    objdir=objs
+    rm -rf $objdir
+    mkdir -p $objdir
+    while [ $i -lt $n ]; do
+        echo "  $compiler -c -O2 $i.cc -o $objdir/$i.o"
+        $compiler -c $i.cc -O2 -o $objdir/$i.o
+        i=$(($i + 1))
+    done
+}
+
+now() {
+    perl -e 'use Time::HiRes qw(time); print time'
+}
+
+elapsed() {
+    perl -e 'use Time::HiRes qw(time); printf("%.3f\n", time - $ARGV[0])' $1
+}
+
+###############################################################################
+
+if [ -n "$CXX" ]; then
+    cxx="$CXX"
+else
+    cxx=c++
+fi
+
+ccache=../ccache
+tmpdir=tmpdir.$$
+CCACHE_DIR=.ccache
+export CCACHE_DIR
+CCACHE_NODIRECT=1
+export CCACHE_NODIRECT
+
+rm -rf $tmpdir
+mkdir $tmpdir
+cd $tmpdir
+
+n=30
+create_src $n
+
+echo "Without ccache:"
+t0=$(now)
+compile $n $cxx
+echo "Time: $(elapsed $t0)"
+
+echo "With ccache, no direct, cache miss:"
+t0=$(now)
+compile $n "$ccache $cxx"
+echo "Time: $(elapsed $t0)"
+
+echo "With ccache, no direct, cache hit:"
+t0=$(now)
+compile $n "$ccache $cxx"
+echo "Time: $(elapsed $t0)"
+
+unset CCACHE_NODIRECT
+CCACHE_LOGFILE=ccache.log
+export CCACHE_LOGFILE
+rm -rf $CCACHE_DIR
+
+echo "With ccache, direct, cache miss:"
+t0=$(now)
+compile $n "$ccache $cxx"
+echo "Time: $(elapsed $t0)"
+
+echo "With ccache, direct, cache hit:"
+t0=$(now)
+compile $n "$ccache $cxx"
+echo "Time: $(elapsed $t0)"