[master] 5a26bb816 varnishstat: Key binding to reset running averages

[Dridi Boukelmoune]

commit 5a26bb8160c7099593f4a212b065fd01637f9629
Author: Guillaume Quintard <guillaume.quintard at varnish-software.com>
Date:   Thu Feb 13 18:38:26 2025 -0800

    varnishstat: Key binding to reset running averages
    
    I've been running benchmark tests these last few days, and I've been
    wishing to be able to reset the average calculations without having to
    restart varnishstat, so here we go.

diff --git a/bin/varnishstat/varnishstat_bindings.h b/bin/varnishstat/varnishstat_bindings.h
index 565b5cc49..c4a79ad56 100644
--- a/bin/varnishstat/varnishstat_bindings.h
+++ b/bin/varnishstat/varnishstat_bindings.h
@@ -101,6 +101,9 @@ BINDING(QUIT, "\tQuit.")
 BINDING_KEY(BINDING_CTRL('t'), "CTRL+T",)
 BINDING(SAMPLE, "\tSample now.")
 
+BINDING_KEY('0', "0",)
+BINDING(RESET_AVERAGES, "\tReset averages.")
+
 BINDING_KEY('+', "+",)
 BINDING(ACCEL, "\tIncrease refresh interval.")
 
diff --git a/bin/varnishstat/varnishstat_curses.c b/bin/varnishstat/varnishstat_curses.c
index 6250c8512..d1a1cb219 100644
--- a/bin/varnishstat/varnishstat_curses.c
+++ b/bin/varnishstat/varnishstat_curses.c
@@ -129,6 +129,7 @@ static int current = 0;
 static int rebuild = 0;
 static int redraw = 0;
 static int sample = 0;
+static int reset_averages = 0;
 static int scale = 1;
 static double t_sample = 0.;
 static double interval = 1.;
@@ -262,6 +263,12 @@ sample_points(void)
 		pt->t_last = pt->t_cur;
 		pt->t_cur = VTIM_mono();
 
+		if (reset_averages) {
+			pt->chg = 0;
+			pt->ma_10.n = 0;
+			pt->ma_100.n = 0;
+			pt->ma_1000.n = 0;
+		}
 		if (pt->t_last)
 			pt->chg = ((int64_t)pt->cur - (int64_t)pt->last) /
 			    (pt->t_cur - pt->t_last);
@@ -305,6 +312,11 @@ sample_hitrate(void)
 		ratio = hr / (hr + mr);
 	else
 		ratio = 0;
+	if (reset_averages) {
+		hitrate.hr_10.n = 0;
+		hitrate.hr_100.n = 0;
+		hitrate.hr_1000.n = 0;
+	}
 	update_ma(&hitrate.hr_10, ratio);
 	update_ma(&hitrate.hr_100, ratio);
 	update_ma(&hitrate.hr_1000, ratio);
@@ -318,6 +330,7 @@ sample_data(void)
 	redraw = 1;
 	sample_points();
 	sample_hitrate();
+	reset_averages = 0;
 }
 
 static void
@@ -1006,6 +1019,9 @@ handle_points_keypress(struct vsc *vsc, enum kb_e kb)
 	case KB_SAMPLE:
 		sample = 1;
 		return;
+	case KB_RESET_AVERAGES:
+		reset_averages = 1;
+		return;
 	case KB_QUIT:
 	case KB_SIG_INT:
 	case KB_SIG_TSTP:
@@ -1055,6 +1071,7 @@ handle_help_keypress(enum kb_e kb)
 	case KB_VERBOSE:
 	case KB_QUIET:
 	case KB_SAMPLE:
+	case KB_RESET_AVERAGES:
 		break;
 	case KB_QUIT:
 	case KB_SIG_INT:
diff --git a/bin/varnishtest/tests/u00021.vtc b/bin/varnishtest/tests/u00021.vtc
new file mode 100644
index 000000000..0bc3ba8a9
--- /dev/null
+++ b/bin/varnishtest/tests/u00021.vtc
@@ -0,0 +1,23 @@
+varnishtest "varnishstat coverage"
+
+
+server s1 {
+	rxreq
+	txresp
+} -start
+
+varnish v1 -vcl+backend {} -start
+process p1 -dump {varnishstat -n ${v1_name}} -start
+delay 2
+
+client c1 -repeat 11 {
+	txreq
+	rxresp
+} -run
+
+delay 2
+process p1 -screen_dump
+process p1 -write 0
+delay 1
+process p1 -screen_dump
+process p1 -expect-text 0 0 "avg(n):   0.0000   0.0000   0.0000"