#!/bin/bash
# by TB : 2012-10-12

if [ "$USER" != "root" ]
then
	echo "You must be root to execute this script (in order to instruct the kernel to drop the cache)!" 
	exit 1
fi

if [ -z "$1" ]
then 
	TESTFILE=`mktemp`
else
	DIR="$1"
	[ ! -d "$DIR" ] && { echo "$DIR must be a directory"; exit 1; }
	echo "Are you sure you want to use $DIR as a test file directory. CTRL-C to abort" && read
	TESTFILE=$(mktemp --tmpdir=$DIR)
	
fi
DD_SIZE="bs=64k count=16k"

function cleanup {
	echo 'exiting, removing test file';
	rm ${TESTFILE};

}

function do_dd_test {
	echo -n "$1 ==>" 
	shift
	dd $@ 2>&1 | tail -1 | cut -d, -f3
	echo "===================="
}

trap "{ cleanup; exit 1; }" SIGKILL SIGTERM SIGINT

echo "Simple dd Speed Test"
echo "===================="

#Drop cache
echo 3 > /proc/sys/vm/drop_caches
do_dd_test "WRITE TEST" if=/dev/zero of=${TESTFILE} ${DD_SIZE} conv=fdatasync

#Drop cache
echo 3 > /proc/sys/vm/drop_caches

do_dd_test "READ TEST (W/O CACHE)"  if=${TESTFILE} of=/dev/null ${DD_SIZE}
do_dd_test "READ TEST (WITH CACHE)" if=${TESTFILE} of=/dev/null ${DD_SIZE}
cleanup;