tests: overengineer extractloop_plot_csv.m a little

Plot iteration time on second y axis, adjust line styles

tests/stress_tests/extractloop.bash

@@ -93,7 +93,7 @@ function loop {
 		delta=$((t2-t1))
 		if [[ $FSPID -gt 0 && -d /proc ]]; then
 			RSS=$(grep VmRSS /proc/$FSPID/status | tr -s ' ' | cut -f2 -d ' ')
-			echo "$N,$SECONDS,$RSS" >> $CSV
+			echo "$N,$SECONDS,$RSS,$delta" >> $CSV
 		fi
 		echo "[looper $ID] Iteration $N done, $delta seconds, RSS $RSS kiB"
 		let N=$N+1

tests/stress_tests/extractloop_plot_csv.m

@@ -2,9 +2,13 @@
 
 r=csvread('/tmp/extractloop.csv');
 figure('Position',[100,100,1600,800]);
-plot(r(:,2), r(:,3)/1024, '-o');
-xlabel('seconds')
-ylabel('RSS MiB')
+[hAx,hLine1,hLine2] = plotyy(r(:,2), r(:,3)/1024, r(:,2), r(:,4));
+xlabel('Runtime (seconds)')
+set(hLine1, 'LineWidth', 1, 'Marker', 'o', 'MarkerSize', 10)
+% LineWidth also sets the marker drawing thickness
+set(hLine2, 'LineWidth', 1, 'LineStyle', 'none', 'Marker', '*', 'MarkerSize', 10)
+ylabel(hAx(1), 'RSS (MiB)')
+ylabel(hAx(2), 'Iteration Time (seconds)')
 grid on;
 drawnow;
 disp('press enter to exit');