diff --git a/scripts/contrib/bb-perf/bb-matrix-plot.sh b/scripts/contrib/bb-perf/bb-matrix-plot.sh
index 87e8cb1abd..136a25570d 100755
--- a/scripts/contrib/bb-perf/bb-matrix-plot.sh
+++ b/scripts/contrib/bb-perf/bb-matrix-plot.sh
@@ -115,7 +115,7 @@ set xlabel "$XLABEL"
 set ylabel "$YLABEL"
 set style line 100 lt 5 lw 1.5
 $PM3D_FRAGMENT
-set dgrid3d $PM_CNT,$BB_CNT
+set dgrid3d $PM_CNT,$BB_CNT splines
 set ticslevel 0.2
 
 set term png size $SIZE