diff --git a/test/perf/passt_tcp b/test/perf/passt_tcp
index f0cfa1b..bee4f9e 100644
--- a/test/perf/passt_tcp
+++ b/test/perf/passt_tcp
@@ -30,9 +30,9 @@ guest	/sbin/sysctl -w net.ipv4.tcp_rmem="4096 131072 268435456"
 guest	/sbin/sysctl -w net.ipv4.tcp_wmem="4096 131072 268435456"
 guest	/sbin/sysctl -w net.ipv4.tcp_timestamps=0
 
-ns	sysctl -w net.ipv4.tcp_rmem="4096 524288 134217728"
-ns	sysctl -w net.ipv4.tcp_wmem="4096 524288 134217728"
-ns	sysctl -w net.ipv4.tcp_timestamps=0
+ns	/sbin/sysctl -w net.ipv4.tcp_rmem="4096 524288 134217728"
+ns	/sbin/sysctl -w net.ipv4.tcp_wmem="4096 524288 134217728"
+ns	/sbin/sysctl -w net.ipv4.tcp_timestamps=0
 
 gout	GW ip -j -4 route show|jq -rM '.[] | select(.dst == "default").gateway'
 gout	GW6 ip -j -6 route show|jq -rM '.[] | select(.dst == "default").gateway'
diff --git a/test/perf/pasta_tcp b/test/perf/pasta_tcp
index 602ce52..cc21075 100644
--- a/test/perf/pasta_tcp
+++ b/test/perf/pasta_tcp
@@ -16,9 +16,9 @@ nstools	/sbin/sysctl nproc ip seq sleep iperf3 tcp_rr tcp_crr jq sed
 
 test	pasta: throughput and latency (local connections)
 
-ns	sysctl -w net.ipv4.tcp_rmem="131072 524288 134217728"
-ns	sysctl -w net.ipv4.tcp_wmem="131072 524288 134217728"
-ns	sysctl -w net.ipv4.tcp_timestamps=0
+ns	/sbin/sysctl -w net.ipv4.tcp_rmem="131072 524288 134217728"
+ns	/sbin/sysctl -w net.ipv4.tcp_wmem="131072 524288 134217728"
+ns	/sbin/sysctl -w net.ipv4.tcp_timestamps=0
 
 
 set	THREADS 2