diff --git a/samples/net/zperf/prj.conf b/samples/net/zperf/prj.conf
index 59bfa7adb8bf7..129260a113ac7 100644
--- a/samples/net/zperf/prj.conf
+++ b/samples/net/zperf/prj.conf
@@ -44,3 +44,6 @@ CONFIG_SHELL_CMDS_RESIZE=n
 CONFIG_CACHE_MANAGEMENT=y
 CONFIG_SPEED_OPTIMIZATIONS=y
 CONFIG_TIMESLICING=n
+
+# For speed optimizations
+CONFIG_PICOLIBC_USE_MODULE=y