support arbitrary dd options

Usage example: DD_TASKS="1 10 10:bs=1M:oflag=direct"

cases-common.sh

@@ -130,7 +130,7 @@ jbod_12hdd_fallocate_mmap_randwrite_64k()	{ jbod_12hdd randwrite	mmap	1	 64k;	}
 
 dd_job() {
 	job=${nr_dd}dd
-	[[ $bs != 4k ]] && job+=":bs=$bs"
+	[[ $dd_opt ]] && job+=":$dd_opt"
 	echo $job
 }
 

dd-common.sh

@@ -20,7 +20,7 @@ run_dd() {
 			mnt=$MNT/$(basename $dev)
 			rm -f $mnt/zero-$i
 			# ulimit -m $((i<<10))
-			dd bs=$bs if=/dev/zero of=$mnt/zero-$i &
+			dd $(echo $dd_opt | tr : ' ') if=/dev/zero of=$mnt/zero-$i &
 			echo $! >> pid
 			# sleep 5
 		done

main-loop.sh

@@ -34,6 +34,11 @@ do
 	[[ $fs =~ nfs ]] && devices=$NFS_DEVICE
 	RAID_LEVEL=jbod
 
+	[[ $nr_dd =~ : ]] && {
+		dd_opt=$(echo $nr_dd | cut -f2- -d:)
+		nr_dd=$(echo $nr_dd | cut -f1 -d:)
+	}
+
 	cd $BASE_DIR
 
 	if [[ $scheme =~ ^fio_ && -f $scheme ]]; then