Draw every panel figure from the latest sample instead of holding the totals

main.go

@@ -55,24 +55,8 @@ type direction struct {
 	drops       uint64
 	base        counterSet
 
-	heldFrames heldValue
-	heldBytes  heldValue
-	nic        atomic.Uint64
-	poller     *nicPoller
-}
-
-// Monotonic totals climb by tens of thousands per frame, which is unreadable
-// churn at 60Hz, so the drawn value is held and refreshed a few times a second.
-type heldValue struct {
-	v  uint64
-	at time.Time
-}
-
-func (h *heldValue) get(now time.Time, cur uint64) uint64 {
-	if now.Sub(h.at) >= totalsHold {
-		h.v, h.at = cur, now
-	}
-	return h.v
+	nic    atomic.Uint64
+	poller *nicPoller
 }
 
 // Everything the display reads, taken at one instant, so a pair of these
@@ -238,8 +222,6 @@ func (d *direction) reset() {
 	d.win.push(d.base)
 	d.mu.Unlock()
 
-	d.heldFrames = heldValue{}
-	d.heldBytes = heldValue{}
 	d.cable.reset()
 }
 
@@ -361,7 +343,7 @@ func (d *direction) sample() {
 
 // Draws what the sampler last put in the ring rather than reading the counters
 // again, so the display never participates in the measurement.
-func (d *direction) displayView(t time.Time) view {
+func (d *direction) displayView() view {
 	d.mu.Lock()
 	n := d.win.count()
 	if n == 0 {
@@ -377,9 +359,6 @@ func (d *direction) displayView(t time.Time) view {
 	v.txGbps = d.win.latest(txRateGbps)
 	v.rxGbps = d.win.latest(rxRateGbps)
 	d.mu.Unlock()
-
-	v.rxFrames = d.heldFrames.get(t, v.rxFrames)
-	v.rxBytes = d.heldBytes.get(t, v.rxBytes)
 	return v
 }
 
@@ -569,7 +548,6 @@ const (
 	// How far back the shown errors reach and how many buckets the median runs
 	// over, so a step in the rate lands half this late.
 	rateWindowSpan = time.Second
-	totalsHold     = 50 * time.Millisecond
 )
 
 // One sampler for both directions, so they are read back to back on one clock
@@ -734,7 +712,7 @@ func run(aName, bName string, nsPerM float64) error {
 				start = resetAll(dirs, stats)
 			}
 			for i, d := range dirs {
-				views[i] = d.displayView(now)
+				views[i] = d.displayView()
 			}
 			// Empty until the probe has a stamp from each direction, so the
 			// panel shows nothing there rather than a placeholder.

main_test.go

@@ -1,9 +1,6 @@
 package main
 
-import (
-	"testing"
-	"time"
-)
+import "testing"
 
 // A reset re-bases from a fresh capture while the ring still holds buckets from
 // just before it, so the newest bucket must not be left behind the new origin.
@@ -22,7 +19,7 @@ func TestResetDoesNotUnderflowTotals(t *testing.T) {
 	d.rxStats[0].bytes.Store(9600)
 	d.reset()
 
-	v := d.displayView(time.Now())
+	v := d.displayView()
 	if v.rxFrames != 0 {
 		t.Errorf("rxFrames = %d, want 0", v.rxFrames)
 	}