Aggregate all net interfaces, remove n hotkey, fix net bar decay bugv0.9.0

Sum RX/TX across all non-lo interfaces instead of picking a single one.
Remove the n hotkey (cycle interface), netint config field, and --netint
flag since they are no longer needed. Fix pre-existing bug where net bars
decayed to zero between collector updates (~19 of 20 frames had target=0,
making bars invisible even during heavy downloads).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

7 files changed, 140 insertions, 159 deletions

diff --git a/AGENTS.md b/AGENTS.md
index ab005e5..28af89c 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -51,15 +51,15 @@ Default when no hosts are given: `localhost`. No SSH required for local use.
 ## Display and hotkeys
 
 - **Display** (`internal/display`): One loop – poll events, snapshot from store, count bars, clear only when layout/size changes, draw CPU then mem then net per host, present. Bar width = `winW / numBars`; no gap between bars (avoids 1px artifacts).
-- **Hotkeys:** 1=cores, 2=mem, 3=net, e=extended (peak line), h=help, n=cycle net iface, q=quit, w=write config, a/y=cpu avg, d/c=net avg, arrows=resize. See README “Hotkeys” table.
+- **Hotkeys:** 1=cores, 2=mem, 3=net, e=extended (peak line), h=help, q=quit, w=write config, a/y=cpu avg, d/c=net avg, f/v=link scale, arrows=resize. See README "Hotkeys" table.
 
-Network interface: chosen by `netint` config or first non-`lo`; press `n` to cycle. When net is toggled on, stdout prints which interface is used and how to set `netint`/`netlink`.
+Network bars aggregate RX/TX across all non-`lo` interfaces per host. Link speed is set via `netlink` config or `--netlink` flag.
 
 ## Conventions
 
 - Prefer the existing `internal/*` package layout; avoid adding new toplevel Go packages unless necessary.
 - Version is the single source in `internal/version/version.go`.
-- Config keys are lowercase in `~/.loadbarsrc` (e.g. `netint=eth0`, `netlink=gbit`).
+- Config keys are lowercase in `~/.loadbarsrc` (e.g. `netlink=gbit`).
 - No text/font rendering in the SDL window in the current design; keep feedback on stdout unless the user explicitly asks for in-window labels.
 
 ## Testing
diff --git a/README.md b/README.md
index 5fe02ea..3c2c6cf 100644
--- a/README.md
+++ b/README.md
@@ -109,10 +109,9 @@ Press these keys while loadbars is running (see also `h` for a short list on std
 |-----|--------|
 | **1** | Toggle CPU cores (one bar per core vs one aggregate bar per host) |
 | **2** | Toggle memory bars (RAM left, Swap right per host) |
-| **3** | Toggle network bars (RX/TX per host); stdout shows which interface is used |
+| **3** | Toggle network bars (RX/TX summed across all non-lo interfaces per host) |
 | **e** | Toggle extended display (1px peak line on CPU bars: max system+user over last samples) |
 | **h** | Print hotkey list to stdout |
-| **n** | Cycle to next network interface (per host); only when net bars are shown |
 | **q** | Quit |
 | **w** | Write current settings to ~/.loadbarsrc |
 | **a** | Increase CPU average samples (affects extended peak history length) |
@@ -148,13 +147,9 @@ Press these keys while loadbars is running (see also `h` for a short list on std
 - `Rxb` = Incoming (received) traffic in %, Color: Light green, normal green if >100% while using low netlink reference. Bar comes from top and is half width.
 - `Txb` = Outgoing (transmitted) traffic in %, Color: Light green, normal green if >100% while using low netlink reference. Bar comes from bottom and is half width.
 
-When network bar is red: The interface does not exist on the specific remote host.
+When network bar is red: No non-loopback interface exists on the specific remote host.
 
-**Choosing the network interface:** By default loadbars uses the first non-loopback interface (e.g. `eth0`, `enp0s3`). If stats never change, you may be watching the wrong interface (e.g. `docker0` with little traffic). Set the interface explicitly:
-
-- In **~/.loadbarsrc**: `netint=eth0` (use the name from `/proc/net/dev` or `ip link`)
-- On the command line: `loadbars --netint eth0 --hosts localhost`
-- In-app: press **3** to show net bars (stdout will print which interface is used), then **n** to cycle to the next interface.
+**Aggregated interfaces:** Loadbars sums RX/TX across all non-loopback interfaces (e.g. `eth0`, `wlan0`, `enp0s3`) and shows the combined total. Loopback (`lo`) is always excluded.
 
 **Link speed** (`netlink`): Used to compute utilization %. Default is `gbit`. Set e.g. `netlink=100mbit` or `netlink=10gbit` in ~/.loadbarsrc or `--netlink 100mbit`.
 
@@ -164,7 +159,6 @@ Loadbars tries to read ~/.loadbarsrc and it's possible to configure any option y
 
 ```
 showcores=1   # Always show cores on startup
-netint=eth0   # Interface for network bars (optional)
 netlink=gbit  # Link speed for utilization % (optional)
 ```
 
diff --git a/cmd/loadbars/main.go b/cmd/loadbars/main.go
index cd834ab..3d7fe77 100644
--- a/cmd/loadbars/main.go
+++ b/cmd/loadbars/main.go
@@ -26,7 +26,6 @@ func main() {
 	flag.IntVar(&cfg.MaxWidth, "maxwidth", cfg.MaxWidth, "Set max width")
 	flag.IntVar(&cfg.CPUAverage, "cpuaverage", cfg.CPUAverage, "Num of CPU samples for avg")
 	flag.IntVar(&cfg.NetAverage, "netaverage", cfg.NetAverage, "Num of net samples for avg")
-	flag.StringVar(&cfg.NetInt, "netint", cfg.NetInt, "Interface to show netstats for")
 	flag.StringVar(&cfg.NetLink, "netlink", cfg.NetLink, "Link speed (mbit, 10mbit, 100mbit, gbit, 10gbit or number)")
 	flag.BoolVar(&cfg.ShowCores, "showcores", cfg.ShowCores, "Toggle core display")
 	flag.BoolVar(&cfg.ShowMem, "showmem", cfg.ShowMem, "Toggle mem display")
@@ -119,16 +118,13 @@ Options:
   --height <n>       Window height (default 150)
   --showcores        Show per-CPU bars
   --showmem          Show memory bars
-  --shownet          Show network bars
-  --netint <iface>   Network interface for net bars (e.g. eth0, enp0s3).
-                     Default: first non-lo. Press 'n' in-app to cycle.
+  --shownet          Show network bars (aggregates all non-lo interfaces)
   --netlink <speed>  Link speed for %% (gbit, 10gbit, mbit, 100mbit, or number).
                      Default: gbit.
   --extended         Extended display (peak line)
   --help             This help
   --version          Print version
 
-Config: netint and netlink can be set in ~/.loadbarsrc. Press '3' then see
-stdout for which interface is used; press 'n' to cycle. Press 'h' for hotkeys.
+Config: netlink can be set in ~/.loadbarsrc. Press 'h' for hotkeys.
 `, version.Version, constants.CSSHConfFile)
 }
diff --git a/internal/config/config.go b/internal/config/config.go
index e523372..0fc80d4 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -23,7 +23,6 @@ type Config struct {
 	Height     int
 	MaxWidth   int
 	NetAverage int
-	NetInt     string
 	NetLink    string
 	ShowCores  bool
 	ShowMem    bool
@@ -104,7 +103,7 @@ func (c *Config) parseReader(f *os.File) error {
 	validKeys := map[string]bool{
 		"title": true, "barwidth": true, "cpuaverage": true, "extended": true,
 		"hasagent": true, "height": true, "maxwidth": true, "netaverage": true,
-		"netint": true, "netlink": true, "showcores": true, "showmem": true,
+		"netlink": true, "showcores": true, "showmem": true,
 		"shownet": true, "sshopts": true, "cluster": true,
 	}
 	scanner := bufio.NewScanner(f)
@@ -158,8 +157,6 @@ func (c *Config) set(key, val string) {
 		if n, err := strconv.Atoi(val); err == nil {
 			c.NetAverage = n
 		}
-	case "netint":
-		c.NetInt = val
 	case "netlink":
 		c.NetLink = val
 	case "showcores":
@@ -198,7 +195,6 @@ func (c *Config) writeTo(f *os.File) error {
 	writeInt("height", c.Height)
 	writeInt("maxwidth", c.MaxWidth)
 	writeInt("netaverage", c.NetAverage)
-	writeStr("netint", c.NetInt)
 	writeStr("netlink", c.NetLink)
 	writeBool("showcores", c.ShowCores)
 	writeBool("showmem", c.ShowMem)
diff --git a/internal/display/display.go b/internal/display/display.go
index b5ed092..3b4dd42 100644
--- a/internal/display/display.go
+++ b/internal/display/display.go
@@ -21,40 +21,35 @@ const smoothFactor = 0.12 // blend toward target each frame; lower = smoother
 
 // runState holds mutable state across the display loop (hotkeys, window size, smoothed data).
 type runState struct {
-	showCores       bool
-	showMem         bool
-	showNet         bool
-	extended        bool
-	winW            int32
-	winH            int32
-	prevCPU         map[string]collector.CPULine
-	smoothedCPU     map[string]*[9]float64
-	smoothedMem     map[string]*struct{ ramUsed, swapUsed float64 }
-	smoothedNet     map[string]*struct{ rxPct, txPct float64 }
-	prevNet         map[string]stats.NetStamp
-	netIntIndex     map[string]int
-	cycleNetNext    bool
-	printNetInfoOnce bool
-	peakHistory     map[string][]float64
+	showCores   bool
+	showMem     bool
+	showNet     bool
+	extended    bool
+	winW        int32
+	winH        int32
+	prevCPU     map[string]collector.CPULine
+	smoothedCPU map[string]*[9]float64
+	smoothedMem map[string]*struct{ ramUsed, swapUsed float64 }
+	smoothedNet map[string]*struct{ rxPct, txPct float64 }
+	prevNet     map[string]stats.NetStamp // aggregated (summed) previous net stamp per host
+	peakHistory map[string][]float64
 }
 
 // newRunState builds initial run state from config.
 func newRunState(cfg *config.Config, winW, winH int32) *runState {
 	return &runState{
-		showCores:        cfg.ShowCores,
-		showMem:          cfg.ShowMem,
-		showNet:          cfg.ShowNet,
-		extended:         cfg.Extended,
-		winW:             winW,
-		winH:             winH,
-		prevCPU:          make(map[string]collector.CPULine),
-		smoothedCPU:      make(map[string]*[9]float64),
-		smoothedMem:      make(map[string]*struct{ ramUsed, swapUsed float64 }),
-		smoothedNet:      make(map[string]*struct{ rxPct, txPct float64 }),
-		prevNet:          make(map[string]stats.NetStamp),
-		netIntIndex:      make(map[string]int),
-		printNetInfoOnce: cfg.ShowNet,
-		peakHistory:      make(map[string][]float64),
+		showCores:   cfg.ShowCores,
+		showMem:     cfg.ShowMem,
+		showNet:     cfg.ShowNet,
+		extended:    cfg.Extended,
+		winW:        winW,
+		winH:        winH,
+		prevCPU:     make(map[string]collector.CPULine),
+		smoothedCPU: make(map[string]*[9]float64),
+		smoothedMem: make(map[string]*struct{ ramUsed, swapUsed float64 }),
+		smoothedNet: make(map[string]*struct{ rxPct, txPct float64 }),
+		prevNet:     make(map[string]stats.NetStamp),
+		peakHistory: make(map[string][]float64),
 	}
 }
 
@@ -152,9 +147,6 @@ func handleKey(sym sdl.Keycode, window *sdl.Window, cfg *config.Config, state *r
 	case sdl.K_3:
 		state.showNet = !state.showNet
 		fmt.Println("==> Toggled show net:", state.showNet)
-		if state.showNet {
-			state.printNetInfoOnce = true
-		}
 	case sdl.K_e:
 		state.extended = !state.extended
 		fmt.Println("==> Toggled extended (peak line):", state.extended)
@@ -180,11 +172,6 @@ func handleKey(sym sdl.Keycode, window *sdl.Window, cfg *config.Config, state *r
 		scaleLinkDown(cfg)
 	case sdl.K_h:
 		printHotkeys()
-	case sdl.K_n:
-		state.cycleNetNext = true
-		if state.showNet {
-			fmt.Println("==> Cycling to next network interface (per host)")
-		}
 	case sdl.K_w:
 		cfg.ShowCores = state.showCores
 		cfg.ShowMem = state.showMem
@@ -223,16 +210,6 @@ func handleKey(sym sdl.Keycode, window *sdl.Window, cfg *config.Config, state *r
 // drawFrame updates state from snapshot, clears if layout changed, and draws all bars.
 func drawFrame(renderer *sdl.Renderer, src stats.Source, cfg *config.Config, state *runState) {
 	snap := src.Snapshot()
-	if state.cycleNetNext {
-		for _, host := range sortedHosts(snap) {
-			state.netIntIndex[host]++
-		}
-		state.cycleNetNext = false
-	}
-	if state.printNetInfoOnce && state.showNet {
-		state.printNetInfoOnce = false
-		printNetInterfaceHelp(snap, cfg, state.netIntIndex)
-	}
 	numBars := countBars(snap, state.showCores, state.showMem, state.showNet)
 	barWidth := state.winW / int32(numBars)
 	if barWidth < 1 {
@@ -314,7 +291,7 @@ func drawHostBars(renderer *sdl.Renderer, h *stats.HostStats, host string, cfg *
 		if state.smoothedNet[host] == nil {
 			state.smoothedNet[host] = &struct{ rxPct, txPct float64 }{}
 		}
-		state.prevNet[host] = drawNetBarSmoothed(renderer, h, cfg, state.smoothedNet[host], state.prevNet[host], state.netIntIndex, host, smoothFactor, barWidth, x, winH)
+		state.prevNet[host] = drawNetBarSmoothed(renderer, h, cfg, state.smoothedNet[host], state.prevNet[host], smoothFactor, barWidth, x, winH)
 	}
 }
 
@@ -526,35 +503,9 @@ func drawMemBarSmoothed(renderer *sdl.Renderer, h *stats.HostStats, smoothed *st
 }
 
 func printHotkeys() {
-	fmt.Println("=> Hotkeys: 1=cores 2=mem 3=net e=extended h=help n=next net q=quit w=write config a/y=cpu avg d/c=net avg f/v=link scale arrows=resize")
+	fmt.Println("=> Hotkeys: 1=cores 2=mem 3=net e=extended h=help q=quit w=write config a/y=cpu avg d/c=net avg f/v=link scale arrows=resize")
 }
 
-// printNetInterfaceHelp prints which interface is used per host and how to set netint (when net view is toggled on).
-func printNetInterfaceHelp(snap map[string]*stats.HostStats, cfg *config.Config, netIntIndex map[string]int) {
-	for _, host := range sortedHosts(snap) {
-		h := snap[host]
-		if h == nil || h.Net == nil || len(h.Net) == 0 {
-			fmt.Printf("Net: %s => (no interfaces yet, wait for data)\n", host)
-			continue
-		}
-		iface := chooseNetIface(h, cfg, host, netIntIndex)
-		all := make([]string, 0, len(h.Net))
-		for name := range h.Net {
-			all = append(all, name)
-		}
-		sort.Strings(all)
-		if iface == "" {
-			fmt.Printf("Net: %s => (no non-lo interface; seen: %s)\n", host, strings.Join(all, ", "))
-			continue
-		}
-		hint := "set netint=IFACE in ~/.loadbarsrc or --netint IFACE"
-		if cfg.NetInt != "" {
-			hint = "using netint=" + cfg.NetInt + " from config"
-		}
-		fmt.Printf("Net: %s => %s (all: %s). %s\n", host, iface, strings.Join(all, ", "), hint)
-	}
-	fmt.Println("=> Link speed: netlink=" + cfg.NetLink + " (gbit/mbit/10mbit/100mbit/10gbit or number). Change in ~/.loadbarsrc or --netlink")
-}
 
 // netLinkBytesPerSec returns link speed in bytes/sec from cfg.NetLink (e.g. "gbit", "10gbit", "100mbit", or numeric mbit).
 
@@ -616,58 +567,54 @@ func netLinkBytesPerSec(cfg *config.Config) int64 {
 	return int64(constants.BytesGbit)
 }
 
-// chooseNetIface returns the interface name to use for this host: cfg.NetInt if set and present, else first non-lo, cycling with n key.
-func chooseNetIface(h *stats.HostStats, cfg *config.Config, host string, netIntIndex map[string]int) string {
-	if h.Net == nil || len(h.Net) == 0 {
-		return ""
-	}
-	if cfg.NetInt != "" {
-		if _, ok := h.Net[cfg.NetInt]; ok {
-			return cfg.NetInt
-		}
+// sumNonLoNet aggregates RX (B) and TX (Tb) bytes across all non-lo interfaces,
+// using the latest timestamp from any interface.
+func sumNonLoNet(h *stats.HostStats) (sum stats.NetStamp, hasIface bool) {
+	if h.Net == nil {
+		return sum, false
 	}
-	names := make([]string, 0, len(h.Net))
-	for iface := range h.Net {
+	for iface, ns := range h.Net {
 		if iface == "lo" {
 			continue
 		}
-		names = append(names, iface)
-	}
-	sort.Strings(names)
-	if len(names) == 0 {
-		return ""
-	}
-	idx := netIntIndex[host] % len(names)
-	if idx < 0 {
-		idx += len(names)
+		hasIface = true
+		sum.B += ns.B
+		sum.Tb += ns.Tb
+		if ns.Stamp > sum.Stamp {
+			sum.Stamp = ns.Stamp
+		}
 	}
-	return names[idx]
+	return sum, hasIface
 }
 
-func drawNetBarSmoothed(renderer *sdl.Renderer, h *stats.HostStats, cfg *config.Config, smoothed *struct{ rxPct, txPct float64 }, prev stats.NetStamp, netIntIndex map[string]int, host string, factor float64, barW int32, x *int32, winH int32) stats.NetStamp {
+// drawNetBarSmoothed sums RX/TX across all non-lo interfaces, computes utilization
+// vs link speed, smooths toward target, and draws one net bar (RX left from top, TX right from bottom).
+// Smoothed values and prevNet are only updated when new collector data arrives
+// (cur.Stamp > prev.Stamp), so the bar holds steady between collector cycles
+// instead of decaying toward zero on frames with no new data.
+func drawNetBarSmoothed(renderer *sdl.Renderer, h *stats.HostStats, cfg *config.Config, smoothed *struct{ rxPct, txPct float64 }, prev stats.NetStamp, factor float64, barW int32, x *int32, winH int32) stats.NetStamp {
 	defer func() { *x += barW }()
 	// Clear this slot so we never leave previous (e.g. CPU/mem) content visible
 	renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
 	renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: barW, H: winH})
-	iface := chooseNetIface(h, cfg, host, netIntIndex)
-	if iface == "" {
-		renderer.SetDrawColor(constants.Red.R, constants.Red.G, constants.Red.B, 255)
-		renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: barW, H: winH})
-		return prev
-	}
-	cur, ok := h.Net[iface]
-	if !ok {
+	cur, hasIface := sumNonLoNet(h)
+	if !hasIface {
+		// No non-lo interface: show red bar
 		renderer.SetDrawColor(constants.Red.R, constants.Red.G, constants.Red.B, 255)
 		renderer.FillRect(&sdl.Rect{X: *x, Y: 0, W: barW, H: winH})
 		return prev
 	}
-	linkBps := netLinkBytesPerSec(cfg)
-	if linkBps <= 0 {
-		linkBps = int64(constants.BytesGbit)
-	}
-	var targetRx, targetTx float64
-	if prev.Stamp > 0 && cur.Stamp > prev.Stamp {
-		dt := float64(cur.Stamp-prev.Stamp) / 1e9
+	// Only recompute and smooth when the collector has provided new data.
+	// The collector updates net stamps every ~2.8s, but drawFrame runs every
+	// ~0.14s. Without this guard, the 19 intermediate frames would set
+	// target to 0 (no delta) and smooth the bar toward zero, making real
+	// traffic invisible.
+	if cur.Stamp > prev.Stamp && prev.Stamp > 0 {
+		linkBps := netLinkBytesPerSec(cfg)
+		if linkBps <= 0 {
+			linkBps = int64(constants.BytesGbit)
+		}
+		dt := cur.Stamp - prev.Stamp
 		if dt > 0 {
 			deltaB := cur.B - prev.B
 			deltaTb := cur.Tb - prev.Tb
@@ -677,12 +624,16 @@ func drawNetBarSmoothed(renderer *sdl.Renderer, h *stats.HostStats, cfg *config.
 			if deltaTb < 0 {
 				deltaTb = 0
 			}
-			targetRx = 100 * float64(deltaB) / (float64(linkBps) * dt)
-			targetTx = 100 * float64(deltaTb) / (float64(linkBps) * dt)
+			targetRx := 100 * float64(deltaB) / (float64(linkBps) * dt)
+			targetTx := 100 * float64(deltaTb) / (float64(linkBps) * dt)
+			smoothed.rxPct += (targetRx - smoothed.rxPct) * factor
+			smoothed.txPct += (targetTx - smoothed.txPct) * factor
 		}
+		prev = cur // only advance prev when we consumed new data
+	} else if prev.Stamp == 0 {
+		// First sample: record it but don't draw yet (no delta available)
+		prev = cur
 	}
-	smoothed.rxPct += (targetRx - smoothed.rxPct) * factor
-	smoothed.txPct += (targetTx - smoothed.txPct) * factor
 
 	halfW := barW / 2
 	barH := float64(winH) / 100.0
@@ -712,5 +663,5 @@ func drawNetBarSmoothed(renderer *sdl.Renderer, h *stats.HostStats, cfg *config.
 		renderer.SetDrawColor(constants.Black.R, constants.Black.G, constants.Black.B, 255)
 		renderer.FillRect(&sdl.Rect{X: *x + halfW, Y: 0, W: halfW, H: winH - txH})
 	}
-	return cur
+	return prev
 }
diff --git a/internal/display/display_test.go b/internal/display/display_test.go
index 841b1d4..94068f6 100644
--- a/internal/display/display_test.go
+++ b/internal/display/display_test.go
@@ -278,7 +278,7 @@ func TestNetBar_RxTx(t *testing.T) {
 					"cpu": {User: 100, System: 100, Idle: 800},
 				},
 				Net: map[string]stats.NetStamp{
-					"eth0": {B: 12500000, Tb: 6250000, Stamp: 2e9}, // current sample
+					"eth0": {B: 12500000, Tb: 6250000, Stamp: 2.0}, // current sample
 				},
 			},
 		},
@@ -288,7 +288,7 @@ func TestNetBar_RxTx(t *testing.T) {
 	state.prevCPU["host1;cpu"] = collector.CPULine{}
 	// Pre-populate prevNet so delta calculation works:
 	// RX: delta=12500000 bytes in 1s = 10% of gbit, TX: 6250000 = 5% of gbit
-	state.prevNet["host1"] = stats.NetStamp{B: 0, Tb: 0, Stamp: 1e9}
+	state.prevNet["host1"] = stats.NetStamp{B: 0, Tb: 0, Stamp: 1.0}
 	// Pre-populate smoothed net so first frame is near target
 	state.smoothedNet["host1"] = &struct{ rxPct, txPct float64 }{
 		rxPct: 10, txPct: 5,
@@ -307,6 +307,60 @@ func TestNetBar_RxTx(t *testing.T) {
 	assertPixelColor(t, surface, 85, 10, constants.Black, tol, "TX free area")
 }
 
+func TestNetBar_AggregatesAllInterfaces(t *testing.T) {
+	const w, h int32 = 100, 100
+
+	renderer, surface, err := createTestRenderer(w, h)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer renderer.Destroy()
+	defer surface.Free()
+
+	cfg := defaultTestConfig()
+	cfg.ShowCores = false
+	cfg.ShowMem = false
+	cfg.ShowNet = true
+	cfg.NetLink = "gbit"
+
+	// Two non-lo interfaces: combined RX = 12500000+12500000 = 25000000 → 20% of gbit
+	src := &mockSource{
+		data: map[string]*stats.HostStats{
+			"host1": {
+				CPU: map[string]collector.CPULine{
+					"cpu": {User: 100, System: 100, Idle: 800},
+				},
+				Net: map[string]stats.NetStamp{
+					"eth0":  {B: 12500000, Tb: 6250000, Stamp: 2.0},
+					"wlan0": {B: 12500000, Tb: 6250000, Stamp: 2.0},
+					"lo":    {B: 99999999, Tb: 99999999, Stamp: 2.0}, // lo must be excluded
+				},
+			},
+		},
+	}
+
+	state := newRunState(cfg, w, h)
+	state.prevCPU["host1;cpu"] = collector.CPULine{}
+	// Previous aggregated stamp: all zeros at t=1
+	state.prevNet["host1"] = stats.NetStamp{B: 0, Tb: 0, Stamp: 1.0}
+	// Pre-populate smoothed to 20% RX, 10% TX (the expected combined values)
+	state.smoothedNet["host1"] = &struct{ rxPct, txPct float64 }{
+		rxPct: 20, txPct: 10,
+	}
+
+	drawFrame(renderer, src, cfg, state)
+
+	const tol = 5
+	// Net bar: 1 CPU + 1 net = 2 bars, each 50px. Net bar at x=50, halfW=25
+	// Left half (RX from top): 20% = 20px of LightGreen from top
+	assertPixelColor(t, surface, 60, 5, constants.LightGreen, tol, "aggregated RX at top")
+	assertPixelColor(t, surface, 60, 45, constants.Black, tol, "RX free area")
+
+	// Right half (TX from bottom): 10% = 10px of LightGreen from bottom
+	assertPixelColor(t, surface, 85, 98, constants.LightGreen, tol, "aggregated TX at bottom")
+	assertPixelColor(t, surface, 85, 10, constants.Black, tol, "TX free area")
+}
+
 func TestMultiHost_BarCount(t *testing.T) {
 	const w, h int32 = 600, 100
 
@@ -332,12 +386,12 @@ func TestMultiHost_BarCount(t *testing.T) {
 			"alpha": {
 				CPU: map[string]collector.CPULine{"cpu": alphaCur},
 				Mem:  map[string]int64{"MemTotal": 100, "MemFree": 50, "SwapTotal": 0, "SwapFree": 0},
-				Net:  map[string]stats.NetStamp{"eth0": {B: 0, Tb: 0, Stamp: 1e9}},
+				Net:  map[string]stats.NetStamp{"eth0": {B: 0, Tb: 0, Stamp: 1.0}},
 			},
 			"beta": {
 				CPU: map[string]collector.CPULine{"cpu": betaCur},
 				Mem:  map[string]int64{"MemTotal": 100, "MemFree": 50, "SwapTotal": 0, "SwapFree": 0},
-				Net:  map[string]stats.NetStamp{"eth0": {B: 0, Tb: 0, Stamp: 1e9}},
+				Net:  map[string]stats.NetStamp{"eth0": {B: 0, Tb: 0, Stamp: 1.0}},
 			},
 		},
 	}
@@ -443,7 +497,7 @@ func TestNetBar_NoInterface(t *testing.T) {
 					"cpu": {User: 100, System: 100, Idle: 800},
 				},
 				Net: map[string]stats.NetStamp{
-					"lo": {B: 0, Tb: 0, Stamp: 1e9}, // only loopback
+					"lo": {B: 0, Tb: 0, Stamp: 1.0}, // only loopback
 				},
 			},
 		},
@@ -573,8 +627,8 @@ func newHotkeyTestEnv(t *testing.T, showCores, showMem, showNet bool) (
 					"SwapFree":  600,
 				},
 				Net: map[string]stats.NetStamp{
-					"eth0": {B: 12500000, Tb: 6250000, Stamp: 2e9},
-					"wlan0": {B: 1000000, Tb: 500000, Stamp: 2e9},
+					"eth0": {B: 12500000, Tb: 6250000, Stamp: 2.0},
+					"wlan0": {B: 1000000, Tb: 500000, Stamp: 2.0},
 				},
 			},
 		},
@@ -584,7 +638,7 @@ func newHotkeyTestEnv(t *testing.T, showCores, showMem, showNet bool) (
 	state.prevCPU["host1;cpu"] = prev
 	state.prevCPU["host1;cpu0"] = prev0
 	state.prevCPU["host1;cpu1"] = prev1
-	state.prevNet["host1"] = stats.NetStamp{B: 0, Tb: 0, Stamp: 1e9}
+	state.prevNet["host1"] = stats.NetStamp{B: 0, Tb: 0, Stamp: 1.0}
 	state.smoothedNet["host1"] = &struct{ rxPct, txPct float64 }{
 		rxPct: 10, txPct: 5,
 	}
@@ -755,16 +809,6 @@ func TestHandleKey_NetAverage(t *testing.T) {
 	}
 }
 
-func TestHandleKey_CycleNet(t *testing.T) {
-	cfg := defaultTestConfig()
-	state := newRunState(cfg, 200, 100)
-
-	handleKey(sdl.K_n, nil, cfg, state)
-	if !state.cycleNetNext {
-		t.Error("expected cycleNetNext=true after pressing 'n'")
-	}
-}
-
 func TestHandleKey_WriteConfig(t *testing.T) {
 	// Set HOME to a temp dir so we don't touch real ~/.loadbarsrc
 	tmpDir := t.TempDir()
diff --git a/internal/version/version.go b/internal/version/version.go
index 2b4ace2..209fae7 100644
--- a/internal/version/version.go
+++ b/internal/version/version.go
@@ -1,4 +1,4 @@
 package version
 
 // Version is the application version (set at build time or here for development).
-const Version = "0.8.4"
+const Version = "0.9.0"