diff --git a/test/perf/passt_tcp b/test/perf/passt_tcp
index 0db12ea..99d8fb1 100644
--- a/test/perf/passt_tcp
+++ b/test/perf/passt_tcp
@@ -141,19 +141,19 @@ tr	TCP throughput over IPv6: host to guest
 bw	-
 bw	-
 ns	ip link set dev lo mtu 1280
-iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__ -w 4M
+iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 1.0 1.2
 ns	ip link set dev lo mtu 1500
-iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__ -w 4M
+iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 2.0 3.0
 ns	ip link set dev lo mtu 9000
-iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__ -w 8M
+iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 5.0 6.0
 ns	ip link set dev lo mtu 65520
-iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__ -w 16M
+iperf3c	ns ::1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 6.0 6.8
 ns	ip link set dev lo mtu 65535
@@ -181,28 +181,28 @@ lat	__LAT__ 500 350
 
 tr	TCP throughput over IPv4: host to guest
 ns	ip link set dev lo mtu 256
-iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -w 1M
+iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 0.3 0.5
 ns	ip link set dev lo mtu 576
-iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -w 1M
+iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 0.5 1.0
 ns	ip link set dev lo mtu 1280
 ns	ip addr add ::1 dev lo
-iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -w 4M
+iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 2.0 3.0
 ns	ip link set dev lo mtu 1500
-iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -w 4M
+iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 2.0 3.0
 ns	ip link set dev lo mtu 9000
-iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -w 8M
+iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 5.0 6.0
 ns	ip link set dev lo mtu 65520
-iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__ -w 16M
+iperf3c	ns 127.0.0.1 100${i}1 __THREADS__ __OPTS__
 iperf3s	BW guest 100${i}1 __THREADS__
 bw	__BW__ 6.0 6.8
 ns	ip link set dev lo mtu 65535