diff --git a/completions/_xfstests.zsh b/completions/_xfstests.zsh
index 16e5282..014e0d5 100644
--- a/completions/_xfstests.zsh
+++ b/completions/_xfstests.zsh
@@ -9,6 +9,7 @@ function _xfstests.zsh() {
 		{-p,--mountpoint}'[the directory to mount the server]: : _files -/' \
 		--nconnect'[number of connections]: :($(seq 1 32))' \
 		{-r,--rdma}'[test using rdma]: :(rxe siw)' \
+		--rwsize'[test with a secific rsize & wsize]: :($(seq 4096 4096 1048576))' \
 		{-q,--scratchmnt}'[the directory to mount the scratch export]: : _files -/' \
 		{-s,--server}'[the server to test against]: : _alternative
 			"hosts\:hosts\: _ssh_hosts"
diff --git a/xfstests.zsh b/xfstests.zsh
index 52f10a5..2dd0153 100755
--- a/xfstests.zsh
+++ b/xfstests.zsh
@@ -10,6 +10,7 @@ zparseopts -D -K \
 	p:=MOUNTPOINT -mountpoint:=MOUNTPOINT \
 	q:=SCRATCHMNT -scratchmnt:=SCRATCHMNT \
 	r:=RDMA -rdma:=RDMA \
+	-rwsize:=RWSIZE \
 	s:=SERVER -server:=SERVER \
 	x:=EXPORT -export:=EXPORT \
 	v+:=VERSION -version+:=VERSION
@@ -41,6 +42,9 @@ prepare_to_test
 if [ ${#NCONNECT} -gt 0 ]; then
 	OPTIONS="$OPTIONS,nconnect=${NCONNECT[-1]}"
 fi
+if [ ${#RWSIZE} -gt 0 ]; then
+	OPTIONS="$OPTIONS,rsize=${RWSIZE[-1]},wsize=${RWSIZE[-1]}"
+fi
 
 testargs=()
 for arg in $*; do