perf(core): build state, workspace and output snapshots in owner scratch

publishState, publishWorkspaces and syncOutputs built fresh snapshots on
every publish only to compare them with the last sent one. They now build
into reused owner-goroutine scratch and copy out only when the snapshot
changed, so a sent value never shares storage with the scratch.

An animation frame on two screens with the state and workspace
subscribers attached: 32 -> 5 allocs, 10.7 KB -> 4.9 KB, 12.7 -> 8.7 us
(BenchmarkPublishSubscribers). The publish budgets drop to 5 (frame) and
3 (leaving). TestPublishSubscribersAllocations guards the budget and the
storage separation and joins perf-check.

Refs: Forgejo #9, GitHub #135

commit: d2493da2bf9da57b95d9f40fc69d210efdd9fd0c
author: brice · 14d ago · 2026-10-08 09:04 UTC
committer: brice · 14d ago · 2026-10-08 09:59 UTC
parent: 4fd770d
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

7 files · +219 -32

M Makefile +1 -1


@@ -69,7 +69,7 @@ adapter-imports:
69	69		[ -z "$$bad" ] \|\| { echo "$$bad"; echo 'adapter imports another adapter: use ports or a shared library (Makefile ADAPTER_LIBS)' >&2; exit 1; }
70	70		# Fast, mandatory guards for tiled content publications and SHM copies.
71	71		perf-check:
72		-	CGO_ENABLED=0 go test ./internal/core ./internal/app ./internal/adapters/drm ./internal/adapters/vulkan ./internal/adapters/wayland -run '^(TestAnimateAllocations\|TestPublishAllocations\|TestPublishStashSlideAllocations\|TestPublishOverviewAllocations\|TestPublishLeavingAllocations\|TestOutputRoutingAllocations\|TestReportSeenAllocations\|TestFrameLifecycleTransitionsAllocations\|TestFullscreenShownAllocations\|TestFrameDecisionAllocations\|TestCommitFrameAllocations\|TestColorPipelineAllocations\|TestShownBySnapshotAllocations\|TestDueFramesAllocations\|TestRenderSteadyStateAllocations\|TestSceneOpaqueRegionAllocations\|TestSceneDeltaAllocations\|TestAccountFlipAllocations\|TestFlipDoneAllocations\|TestSceneWalkUnchangedTiledSHM\|TestTiledCommitPublishAllocations\|TestCapturedCommitApplyAllocations\|TestCapturedViewportApplyAllocations\|TestEffectiveInputEmptyTreeAllocations\|TestHeadlessTiledSHMCallbackAndCopyBudget)$$' -count=1
	72	+	CGO_ENABLED=0 go test ./internal/core ./internal/app ./internal/adapters/drm ./internal/adapters/vulkan ./internal/adapters/wayland -run '^(TestAnimateAllocations\|TestPublishAllocations\|TestPublishSubscribersAllocations\|TestPublishStashSlideAllocations\|TestPublishOverviewAllocations\|TestPublishLeavingAllocations\|TestOutputRoutingAllocations\|TestReportSeenAllocations\|TestFrameLifecycleTransitionsAllocations\|TestFullscreenShownAllocations\|TestFrameDecisionAllocations\|TestCommitFrameAllocations\|TestColorPipelineAllocations\|TestShownBySnapshotAllocations\|TestDueFramesAllocations\|TestRenderSteadyStateAllocations\|TestSceneOpaqueRegionAllocations\|TestSceneDeltaAllocations\|TestAccountFlipAllocations\|TestFlipDoneAllocations\|TestSceneWalkUnchangedTiledSHM\|TestTiledCommitPublishAllocations\|TestCapturedCommitApplyAllocations\|TestCapturedViewportApplyAllocations\|TestEffectiveInputEmptyTreeAllocations\|TestHeadlessTiledSHMCallbackAndCopyBudget)$$' -count=1
73	73		check: vet test arch fakes-check log-check perf-check
74	74
75	75		# On-demand SDR/HDR colour check with examples/testpattern on a headless


@@ -69,7 +69,7 @@ adapter-imports:
69		[ -z "$$bad" ] \|\| { echo "$$bad"; echo 'adapter imports another adapter: use ports or a shared library (Makefile ADAPTER_LIBS)' >&2; exit 1; }	69		[ -z "$$bad" ] \|\| { echo "$$bad"; echo 'adapter imports another adapter: use ports or a shared library (Makefile ADAPTER_LIBS)' >&2; exit 1; }
70		# Fast, mandatory guards for tiled content publications and SHM copies.	70		# Fast, mandatory guards for tiled content publications and SHM copies.
71		perf-check:	71		perf-check:
72	-	CGO_ENABLED=0 go test ./internal/core ./internal/app ./internal/adapters/drm ./internal/adapters/vulkan ./internal/adapters/wayland -run '^(TestAnimateAllocations\|TestPublishAllocations\|TestPublishStashSlideAllocations\|TestPublishOverviewAllocations\|TestPublishLeavingAllocations\|TestOutputRoutingAllocations\|TestReportSeenAllocations\|TestFrameLifecycleTransitionsAllocations\|TestFullscreenShownAllocations\|TestFrameDecisionAllocations\|TestCommitFrameAllocations\|TestColorPipelineAllocations\|TestShownBySnapshotAllocations\|TestDueFramesAllocations\|TestRenderSteadyStateAllocations\|TestSceneOpaqueRegionAllocations\|TestSceneDeltaAllocations\|TestAccountFlipAllocations\|TestFlipDoneAllocations\|TestSceneWalkUnchangedTiledSHM\|TestTiledCommitPublishAllocations\|TestCapturedCommitApplyAllocations\|TestCapturedViewportApplyAllocations\|TestEffectiveInputEmptyTreeAllocations\|TestHeadlessTiledSHMCallbackAndCopyBudget)$$' -count=1	72	+	CGO_ENABLED=0 go test ./internal/core ./internal/app ./internal/adapters/drm ./internal/adapters/vulkan ./internal/adapters/wayland -run '^(TestAnimateAllocations\|TestPublishAllocations\|TestPublishSubscribersAllocations\|TestPublishStashSlideAllocations\|TestPublishOverviewAllocations\|TestPublishLeavingAllocations\|TestOutputRoutingAllocations\|TestReportSeenAllocations\|TestFrameLifecycleTransitionsAllocations\|TestFullscreenShownAllocations\|TestFrameDecisionAllocations\|TestCommitFrameAllocations\|TestColorPipelineAllocations\|TestShownBySnapshotAllocations\|TestDueFramesAllocations\|TestRenderSteadyStateAllocations\|TestSceneOpaqueRegionAllocations\|TestSceneDeltaAllocations\|TestAccountFlipAllocations\|TestFlipDoneAllocations\|TestSceneWalkUnchangedTiledSHM\|TestTiledCommitPublishAllocations\|TestCapturedCommitApplyAllocations\|TestCapturedViewportApplyAllocations\|TestEffectiveInputEmptyTreeAllocations\|TestHeadlessTiledSHMCallbackAndCopyBudget)$$' -count=1
73		check: vet test arch fakes-check log-check perf-check	73		check: vet test arch fakes-check log-check perf-check
74			74
75		# On-demand SDR/HDR colour check with examples/testpattern on a headless	75		# On-demand SDR/HDR colour check with examples/testpattern on a headless

M internal/core/core.go +16 -1


@@ -75,6 +75,7 @@ type Core struct {
75	75		// realBuf backs the layout read through at once by publish (each
76	76		// workspace while overviewReal is filled) and by state(); never retained.
77	77		realBuf []Placement
	78	+	scratch publishScratch
78	79		security ports.SecurityState
79	80		lock lockState
80	81		inputKeys map[string]bool

@@ -149,6 +150,17 @@ type Core struct {
149	150		pulse focusPulse
150	151		}
151	152
	153	+	// publishScratch is where publishState and publishWorkspaces build their
	154	+	// snapshots each publish: owner goroutine storage, never sent (a snapshot
	155	+	// is copied out of it when it changed).
	156	+	type publishScratch struct {
	157	+	state ports.State
	158	+	workspaces ports.Workspaces
	159	+	shown map[WindowID]bool
	160	+	ids []WindowID
	161	+	layout ports.Layout
	162	+	}
	163	+
152	164		// sentCache is what core last sent to wayland and on its latest-only
153	165		// channels; an unchanged value is not sent again.
154	166		type sentCache struct {

@@ -838,10 +850,13 @@ func (c *Core) warpPointer(ctx context.Context, v ports.PointerWarp) error {
838	850		// syncOutputs sends the output layout when it changed; input learns the
839	851		// geometry only when the outputs themselves moved.
840	852		func (c *Core) syncOutputs(ctx context.Context) error {
841		-	v := ports.SetOutputs{Outputs: c.layout(), Focused: c.cur().name(), Off: c.offOutputs()}
	853	+	// Built in the scratch every publish, copied only when sent.
	854	+	c.scratch.layout = c.layoutInto(c.scratch.layout)
	855	+	v := ports.SetOutputs{Outputs: c.scratch.layout, Focused: c.cur().name(), Off: c.offOutputs()}
842	856		if sameOutputs(v, c.sent.outputs) {
843	857		return nil
844	858		}
	859	+	v.Outputs = append(make(ports.Layout, 0, len(v.Outputs)), v.Outputs...)
845	860		if err := c.command(ctx, v); err != nil {
846	861		return err
847	862		}

 	// realBuf backs the layout read through at once by publish (each
 	// workspace while overviewReal is filled) and by state(); never retained.
 	realBuf         []Placement
+	scratch         publishScratch
 	security        ports.SecurityState
 	lock            lockState
 	inputKeys       map[string]bool
 	pulse focusPulse
 }
+// publishScratch is where publishState and publishWorkspaces build their
+// snapshots each publish: owner goroutine storage, never sent (a snapshot
+// is copied out of it when it changed).
+type publishScratch struct {
+	state      ports.State
+	workspaces ports.Workspaces
+	shown      map[WindowID]bool
+	ids        []WindowID
+	layout     ports.Layout
+}
 // sentCache is what core last sent to wayland and on its latest-only
 // channels; an unchanged value is not sent again.
 type sentCache struct {
 // syncOutputs sends the output layout when it changed; input learns the
 // geometry only when the outputs themselves moved.
 func (c *Core) syncOutputs(ctx context.Context) error {
-	v := ports.SetOutputs{Outputs: c.layout(), Focused: c.cur().name(), Off: c.offOutputs()}
+	// Built in the scratch every publish, copied only when sent.
+	c.scratch.layout = c.layoutInto(c.scratch.layout)
+	v := ports.SetOutputs{Outputs: c.scratch.layout, Focused: c.cur().name(), Off: c.offOutputs()}
 	if sameOutputs(v, c.sent.outputs) {
 		return nil
 	}
+	v.Outputs = append(make(ports.Layout, 0, len(v.Outputs)), v.Outputs...)
 	if err := c.command(ctx, v); err != nil {
 		return err
 	}

M internal/core/layout.go +8 -6


@@ -305,18 +305,20 @@ func (w *Workspace) appendHidden(dst []Placement, floats bool) []Placement {
305	305
306	306		// windows lists every window: columns first, then the stash, then native
307	307		// floats.
308		-	func (w *Workspace) windows() []WindowID {
309		-	var ids []WindowID
	308	+	func (w *Workspace) windows() []WindowID { return w.appendWindows(nil) }
	309	+
	310	+	// appendWindows appends windows' list to dst.
	311	+	func (w *Workspace) appendWindows(dst []WindowID) []WindowID {
310	312		for _, c := range w.Columns {
311		-	ids = append(ids, c.Windows...)
	313	+	dst = append(dst, c.Windows...)
312	314		}
313	315		for _, f := range w.Stash {
314		-	ids = append(ids, f.ID)
	316	+	dst = append(dst, f.ID)
315	317		}
316	318		for _, f := range w.Floats {
317		-	ids = append(ids, f.ID)
	319	+	dst = append(dst, f.ID)
318	320		}
319		-	return ids
	321	+	return dst
320	322		}
321	323
322	324		// cell is the 1-based column and row of a tiled window, 0, 0 otherwise.


@@ -305,18 +305,20 @@ func (w *Workspace) appendHidden(dst []Placement, floats bool) []Placement {
305			305
306		// windows lists every window: columns first, then the stash, then native	306		// windows lists every window: columns first, then the stash, then native
307		// floats.	307		// floats.
308	-	func (w *Workspace) windows() []WindowID {	308	+	func (w *Workspace) windows() []WindowID { return w.appendWindows(nil) }
309	-	var ids []WindowID	309	+
			310	+	// appendWindows appends windows' list to dst.
			311	+	func (w *Workspace) appendWindows(dst []WindowID) []WindowID {
310		for _, c := range w.Columns {	312		for _, c := range w.Columns {
311	-	ids = append(ids, c.Windows...)	313	+	dst = append(dst, c.Windows...)
312		}	314		}
313		for _, f := range w.Stash {	315		for _, f := range w.Stash {
314	-	ids = append(ids, f.ID)	316	+	dst = append(dst, f.ID)
315		}	317		}
316		for _, f := range w.Floats {	318		for _, f := range w.Floats {
317	-	ids = append(ids, f.ID)	319	+	dst = append(dst, f.ID)
318		}	320		}
319	-	return ids	321	+	return dst
320		}	322		}
321			323
322		// cell is the 1-based column and row of a tiled window, 0, 0 otherwise.	324		// cell is the 1-based column and row of a tiled window, 0, 0 otherwise.

M internal/core/publish_alloc_test.go +124 -6


@@ -2,6 +2,8 @@ package core
2	2
3	3		import (
4	4		"context"
	5	+	"reflect"
	6	+	"slices"
5	7		"testing"
6	8		"time"
7	9

@@ -18,15 +20,16 @@ import (
18	20		// flip path with another screen animating keeps it and costs the same), then
19	21		// 6 once the layouts are built in the owner's reused buffers (layoutInto:
20	22		// the screens' layout, the workspaces' column, row and tile rects) instead of
21		-	// fresh slices. What is left is the scenes themselves (windows, separators,
22		-	// the scene set) and the screen placements. Leaving entries (a closed window
23		-	// still fading) add none: 4, less than a frame with six moving windows
	23	+	// fresh slices, and 5 once the output layout is built in the scratch too
	24	+	// (copied only when it changed). What is left is the scenes themselves
	25	+	// (windows, separators, the scene set). Leaving entries (a closed window
	26	+	// still fading) add none: 3, less than a frame with six moving windows
24	27		// (fewer configure targets). The opening overview costs 18 (the stack
25	28		// items, the row map and the neighbor list it rebuilds every frame; its
26	29		// layouts reuse the buffers too).
27	30		const (
28		-	publishAllocBudget = 6
29		-	publishLeavingAllocBudget = 4
	31	+	publishAllocBudget = 5
	32	+	publishLeavingAllocBudget = 3
30	33		publishOverviewAllocBudget = 18
31	34		)
32	35

@@ -34,7 +37,7 @@ const (
34	37		// bookkeeping; the fallback timer is then the system one) with screens
35	38		// screens of six windows each. The Slowdown cap keeps every motion running
36	39		// for seconds, so none settles during a measure even under -race or load.
37		-	func publishRig(t testing.T, screens int) Core {
	40	+	func publishRig(t testing.TB, screens int) *Core {
38	41		t.Helper()
39	42		var cfg ports.Config
40	43		cfg.Keyboard.CmdKey = "super"

@@ -302,3 +305,118 @@ func TestPublishLeavingAllocations(t *testing.T) {
302	305		t.Errorf("publish allocs per frame with leaving entries = %v, budget %d", n, publishLeavingAllocBudget)
303	306		}
304	307		}
	308	+
	309	+	// TestPublishSubscribersAllocations pins the cost of an animation frame
	310	+	// with the state and workspace subscribers attached: their snapshots are
	311	+	// built in the owner's scratch and, unchanged during a camera and rect
	312	+	// animation, add nothing to the frame. Measured: 32 when each publish built
	313	+	// fresh snapshots (state, workspaces and output layout), 5 since. Sent
	314	+	// values never share storage with the scratch they were built in.
	315	+	func TestPublishSubscribersAllocations(t *testing.T) {
	316	+	c := publishRig(t, 2)
	317	+	c.ch.State = make(chan ports.State, 1)
	318	+	c.ch.Workspaces = make(chan ports.Workspaces, 1)
	319	+	t0 := time.Now()
	320	+	for _, sc := range c.screens {
	321	+	if sc.name() == "" {
	322	+	continue
	323	+	}
	324	+	ws := sc.mon.Current()
	325	+	ws.view.motion = c.spring(viewSpring(100, 0), t0)
	326	+	ws.view.off = 100
	327	+	startRectMotions(c, sc, t0)
	328	+	}
	329	+	step := publishStep(t, c, nil)
	330	+	step()
	331	+	checkRunning(t, c, "setup")
	332	+	if len(c.ch.State) != 1 \|\| len(c.ch.Workspaces) != 1 {
	333	+	t.Fatal("setup: no snapshot sent")
	334	+	}
	335	+	st := <-c.ch.State
	336	+	ws := <-c.ch.Workspaces
	337	+	n := testing.AllocsPerRun(50, step)
	338	+	t.Logf("subscribers allocs per step = %v", n)
	339	+	checkRunning(t, c, "motions settled during the measure")
	340	+	if n > publishAllocBudget {
	341	+	t.Errorf("publish allocs per frame with subscribers = %v, budget %d", n, publishAllocBudget)
	342	+	}
	343	+	if len(c.ch.State) != 0 \|\| len(c.ch.Workspaces) != 0 {
	344	+	t.Error("an unchanged snapshot was sent again")
	345	+	}
	346	+	// Sent values own their storage: the next publish rewrites the scratch
	347	+	// in place.
	348	+	sc := &c.scratch
	349	+	if st.Window == nil \|\| len(st.Windows) == 0 \|\| len(ws.Outputs) == 0 \|\| len(c.sent.outputs.Outputs) == 0 {
	350	+	t.Fatalf("setup: empty snapshots %+v %+v", st, ws)
	351	+	}
	352	+	if &st.Windows[0] == &sc.state.Windows[:1][0] \|\| &st.Outputs[0] == &sc.state.Outputs[:1][0] \|\| inSlice(st.Window, sc.state.Windows) \|\| inSlice(st.Window, st.Windows) {
	353	+	t.Error("the sent state shares the scratch")
	354	+	}
	355	+	for _, sent := range []ports.Workspaces{ws, c.sent.workspaces} {
	356	+	if &sent.Outputs[0] == &sc.workspaces.Outputs[:1][0] {
	357	+	t.Error("the sent workspaces share the scratch")
	358	+	}
	359	+	for k, o := range sent.Outputs {
	360	+	if &o.Workspaces[0] == &sc.workspaces.Outputs[k].Workspaces[:1][0] {
	361	+	t.Errorf("the sent workspaces of %s share the scratch", o.Name)
	362	+	}
	363	+	}
	364	+	}
	365	+	if &c.sent.outputs.Outputs[0] == &sc.layout[:1][0] {
	366	+	t.Error("the sent output layout shares the scratch")
	367	+	}
	368	+	// And a later change leaves them as they were.
	369	+	want := ports.State{Output: st.Output, Outputs: slices.Clone(st.Outputs), Windows: slices.Clone(st.Windows)}
	370	+	w := *st.Window
	371	+	want.Window = &w
	372	+	c.windows.setIdleInhibit(st.Windows[0].ID, true)
	373	+	c.publishState()
	374	+	// A sent value aliasing the scratch would always equal it: nothing sent.
	375	+	select {
	376	+	case got := <-c.ch.State:
	377	+	if !got.Windows[0].IdleInhibit {
	378	+	t.Fatal("change not published")
	379	+	}
	380	+	default:
	381	+	t.Fatal("change not published")
	382	+	}
	383	+	if !reflect.DeepEqual(st, want) {
	384	+	t.Fatal("a sent snapshot changed after a later publish")
	385	+	}
	386	+	}
	387	+
	388	+	func inSlice[T any](p *T, s []T) bool {
	389	+	s = s[:cap(s)]
	390	+	for i := range s {
	391	+	if p == &s[i] {
	392	+	return true
	393	+	}
	394	+	}
	395	+	return false
	396	+	}
	397	+
	398	+	// BenchmarkPublishSubscribers is one animation frame on two screens with
	399	+	// the state and workspace subscribers attached.
	400	+	func BenchmarkPublishSubscribers(b *testing.B) {
	401	+	c := publishRig(b, 2)
	402	+	c.ch.State = make(chan ports.State, 1)
	403	+	c.ch.Workspaces = make(chan ports.Workspaces, 1)
	404	+	t0 := time.Now()
	405	+	for _, sc := range c.screens {
	406	+	if sc.name() == "" {
	407	+	continue
	408	+	}
	409	+	ws := sc.mon.Current()
	410	+	ws.view.motion = c.spring(viewSpring(100, 0), t0)
	411	+	ws.view.off = 100
	412	+	startRectMotions(c, sc, t0)
	413	+	}
	414	+	ctx := context.Background()
	415	+	b.ReportAllocs()
	416	+	for b.Loop() {
	417	+	if err := c.step(ctx, nil); err != nil {
	418	+	b.Fatal(err)
	419	+	}
	420	+	<-c.ch.Scenes
	421	+	}
	422	+	}


@@ -2,6 +2,8 @@ package core
2			2
3		import (	3		import (
4		"context"	4		"context"
			5	+	"reflect"
			6	+	"slices"
5		"testing"	7		"testing"
6		"time"	8		"time"
7			9

@@ -18,15 +20,16 @@ import (
18		// flip path with another screen animating keeps it and costs the same), then	20		// flip path with another screen animating keeps it and costs the same), then
19		// 6 once the layouts are built in the owner's reused buffers (layoutInto:	21		// 6 once the layouts are built in the owner's reused buffers (layoutInto:
20		// the screens' layout, the workspaces' column, row and tile rects) instead of	22		// the screens' layout, the workspaces' column, row and tile rects) instead of
21	-	// fresh slices. What is left is the scenes themselves (windows, separators,	23	+	// fresh slices, and 5 once the output layout is built in the scratch too
22	-	// the scene set) and the screen placements. Leaving entries (a closed window	24	+	// (copied only when it changed). What is left is the scenes themselves
23	-	// still fading) add none: 4, less than a frame with six moving windows	25	+	// (windows, separators, the scene set). Leaving entries (a closed window
			26	+	// still fading) add none: 3, less than a frame with six moving windows
24		// (fewer configure targets). The opening overview costs 18 (the stack	27		// (fewer configure targets). The opening overview costs 18 (the stack
25		// items, the row map and the neighbor list it rebuilds every frame; its	28		// items, the row map and the neighbor list it rebuilds every frame; its
26		// layouts reuse the buffers too).	29		// layouts reuse the buffers too).
27		const (	30		const (
28	-	publishAllocBudget = 6	31	+	publishAllocBudget = 5
29	-	publishLeavingAllocBudget = 4	32	+	publishLeavingAllocBudget = 3
30		publishOverviewAllocBudget = 18	33		publishOverviewAllocBudget = 18
31		)	34		)
32			35

@@ -34,7 +37,7 @@ const (
34		// bookkeeping; the fallback timer is then the system one) with screens	37		// bookkeeping; the fallback timer is then the system one) with screens
35		// screens of six windows each. The Slowdown cap keeps every motion running	38		// screens of six windows each. The Slowdown cap keeps every motion running
36		// for seconds, so none settles during a measure even under -race or load.	39		// for seconds, so none settles during a measure even under -race or load.
37	-	func publishRig(t testing.T, screens int) Core {	40	+	func publishRig(t testing.TB, screens int) *Core {
38		t.Helper()	41		t.Helper()
39		var cfg ports.Config	42		var cfg ports.Config
40		cfg.Keyboard.CmdKey = "super"	43		cfg.Keyboard.CmdKey = "super"

@@ -302,3 +305,118 @@ func TestPublishLeavingAllocations(t *testing.T) {
302		t.Errorf("publish allocs per frame with leaving entries = %v, budget %d", n, publishLeavingAllocBudget)	305		t.Errorf("publish allocs per frame with leaving entries = %v, budget %d", n, publishLeavingAllocBudget)
303		}	306		}
304		}	307		}
			308	+
			309	+	// TestPublishSubscribersAllocations pins the cost of an animation frame
			310	+	// with the state and workspace subscribers attached: their snapshots are
			311	+	// built in the owner's scratch and, unchanged during a camera and rect
			312	+	// animation, add nothing to the frame. Measured: 32 when each publish built
			313	+	// fresh snapshots (state, workspaces and output layout), 5 since. Sent
			314	+	// values never share storage with the scratch they were built in.
			315	+	func TestPublishSubscribersAllocations(t *testing.T) {
			316	+	c := publishRig(t, 2)
			317	+	c.ch.State = make(chan ports.State, 1)
			318	+	c.ch.Workspaces = make(chan ports.Workspaces, 1)
			319	+	t0 := time.Now()
			320	+	for _, sc := range c.screens {
			321	+	if sc.name() == "" {
			322	+	continue
			323	+	}
			324	+	ws := sc.mon.Current()
			325	+	ws.view.motion = c.spring(viewSpring(100, 0), t0)
			326	+	ws.view.off = 100
			327	+	startRectMotions(c, sc, t0)
			328	+	}
			329	+	step := publishStep(t, c, nil)
			330	+	step()
			331	+	checkRunning(t, c, "setup")
			332	+	if len(c.ch.State) != 1 \|\| len(c.ch.Workspaces) != 1 {
			333	+	t.Fatal("setup: no snapshot sent")
			334	+	}
			335	+	st := <-c.ch.State
			336	+	ws := <-c.ch.Workspaces
			337	+	n := testing.AllocsPerRun(50, step)
			338	+	t.Logf("subscribers allocs per step = %v", n)
			339	+	checkRunning(t, c, "motions settled during the measure")
			340	+	if n > publishAllocBudget {
			341	+	t.Errorf("publish allocs per frame with subscribers = %v, budget %d", n, publishAllocBudget)
			342	+	}
			343	+	if len(c.ch.State) != 0 \|\| len(c.ch.Workspaces) != 0 {
			344	+	t.Error("an unchanged snapshot was sent again")
			345	+	}
			346	+	// Sent values own their storage: the next publish rewrites the scratch
			347	+	// in place.
			348	+	sc := &c.scratch
			349	+	if st.Window == nil \|\| len(st.Windows) == 0 \|\| len(ws.Outputs) == 0 \|\| len(c.sent.outputs.Outputs) == 0 {
			350	+	t.Fatalf("setup: empty snapshots %+v %+v", st, ws)
			351	+	}
			352	+	if &st.Windows[0] == &sc.state.Windows[:1][0] \|\| &st.Outputs[0] == &sc.state.Outputs[:1][0] \|\| inSlice(st.Window, sc.state.Windows) \|\| inSlice(st.Window, st.Windows) {
			353	+	t.Error("the sent state shares the scratch")
			354	+	}
			355	+	for _, sent := range []ports.Workspaces{ws, c.sent.workspaces} {
			356	+	if &sent.Outputs[0] == &sc.workspaces.Outputs[:1][0] {
			357	+	t.Error("the sent workspaces share the scratch")
			358	+	}
			359	+	for k, o := range sent.Outputs {
			360	+	if &o.Workspaces[0] == &sc.workspaces.Outputs[k].Workspaces[:1][0] {
			361	+	t.Errorf("the sent workspaces of %s share the scratch", o.Name)
			362	+	}
			363	+	}
			364	+	}
			365	+	if &c.sent.outputs.Outputs[0] == &sc.layout[:1][0] {
			366	+	t.Error("the sent output layout shares the scratch")
			367	+	}
			368	+	// And a later change leaves them as they were.
			369	+	want := ports.State{Output: st.Output, Outputs: slices.Clone(st.Outputs), Windows: slices.Clone(st.Windows)}
			370	+	w := *st.Window
			371	+	want.Window = &w
			372	+	c.windows.setIdleInhibit(st.Windows[0].ID, true)
			373	+	c.publishState()
			374	+	// A sent value aliasing the scratch would always equal it: nothing sent.
			375	+	select {
			376	+	case got := <-c.ch.State:
			377	+	if !got.Windows[0].IdleInhibit {
			378	+	t.Fatal("change not published")
			379	+	}
			380	+	default:
			381	+	t.Fatal("change not published")
			382	+	}
			383	+	if !reflect.DeepEqual(st, want) {
			384	+	t.Fatal("a sent snapshot changed after a later publish")
			385	+	}
			386	+	}
			387	+
			388	+	func inSlice[T any](p *T, s []T) bool {
			389	+	s = s[:cap(s)]
			390	+	for i := range s {
			391	+	if p == &s[i] {
			392	+	return true
			393	+	}
			394	+	}
			395	+	return false
			396	+	}
			397	+
			398	+	// BenchmarkPublishSubscribers is one animation frame on two screens with
			399	+	// the state and workspace subscribers attached.
			400	+	func BenchmarkPublishSubscribers(b *testing.B) {
			401	+	c := publishRig(b, 2)
			402	+	c.ch.State = make(chan ports.State, 1)
			403	+	c.ch.Workspaces = make(chan ports.Workspaces, 1)
			404	+	t0 := time.Now()
			405	+	for _, sc := range c.screens {
			406	+	if sc.name() == "" {
			407	+	continue
			408	+	}
			409	+	ws := sc.mon.Current()
			410	+	ws.view.motion = c.spring(viewSpring(100, 0), t0)
			411	+	ws.view.off = 100
			412	+	startRectMotions(c, sc, t0)
			413	+	}
			414	+	ctx := context.Background()
			415	+	b.ReportAllocs()
			416	+	for b.Loop() {
			417	+	if err := c.step(ctx, nil); err != nil {
			418	+	b.Fatal(err)
			419	+	}
			420	+	<-c.ch.Scenes
			421	+	}
			422	+	}

M internal/core/screens.go +5 -2


@@ -157,8 +157,11 @@ func (c *Core) outputConfig(name string) (ports.OutputConfig, bool) {
157	157		}
158	158
159	159		// layout lists the connected outputs; the placeholder is not one.
160		-	func (c *Core) layout() ports.Layout {
161		-	l := make(ports.Layout, 0, len(c.screens))
	160	+	func (c *Core) layout() ports.Layout { return c.layoutInto(make(ports.Layout, 0, len(c.screens))) }
	161	+
	162	+	// layoutInto is layout built in l[:0]: the result aliases l's storage.
	163	+	func (c *Core) layoutInto(l ports.Layout) ports.Layout {
	164	+	l = l[:0]
162	165		for _, s := range c.screens {
163	166		if s.name() != "" {
164	167		l = append(l, s.placement())


@@ -157,8 +157,11 @@ func (c *Core) outputConfig(name string) (ports.OutputConfig, bool) {
157		}	157		}
158			158
159		// layout lists the connected outputs; the placeholder is not one.	159		// layout lists the connected outputs; the placeholder is not one.
160	-	func (c *Core) layout() ports.Layout {	160	+	func (c *Core) layout() ports.Layout { return c.layoutInto(make(ports.Layout, 0, len(c.screens))) }
161	-	l := make(ports.Layout, 0, len(c.screens))	161	+
			162	+	// layoutInto is layout built in l[:0]: the result aliases l's storage.
			163	+	func (c *Core) layoutInto(l ports.Layout) ports.Layout {
			164	+	l = l[:0]
162		for _, s := range c.screens {	165		for _, s := range c.screens {
163		if s.name() != "" {	166		if s.name() != "" {
164		l = append(l, s.placement())	167		l = append(l, s.placement())

M internal/core/state.go +40 -11


@@ -2,28 +2,41 @@ package core
2	2
3	3		import (
4	4		"cmp"
5		-	"reflect"
6	5		"slices"
7	6
8	7		"github.com/bnema/neferwl/internal/ports"
9	8		)
10	9
11		-	// publishState sends the script-facing snapshot when it changed.
	10	+	// publishState sends the script-facing snapshot when it changed. It is
	11	+	// built in the owner's scratch every publish and copied only when sent: an
	12	+	// animation frame that changes nothing allocates nothing here.
12	13		func (c *Core) publishState() {
13	14		if c.ch.State == nil {
14	15		return
15	16		}
16		-	st := c.state()
17		-	if reflect.DeepEqual(st, c.sent.state) {
	17	+	c.scratch.state = c.stateInto(c.scratch.state)
	18	+	// The first snapshot is always sent, even an empty one.
	19	+	if c.sent.state.Outputs != nil && sameState(c.scratch.state, c.sent.state) {
18	20		return
19	21		}
	22	+	st := cloneState(c.scratch.state)
20	23		c.sent.state = st
21	24		latest(c.ch.State, st)
22	25		}
23	26
24		-	// state builds the snapshot. The placeholder screen is not an output.
25		-	func (c *Core) state() ports.State {
26		-	st := ports.State{Output: c.cur().name(), Outputs: []ports.OutputState{}, Windows: []ports.WindowState{}}
	27	+	// state is a fresh snapshot, the caller's to keep.
	28	+	func (c *Core) state() ports.State { return cloneState(c.stateInto(ports.State{})) }
	29	+
	30	+	// stateInto builds the snapshot in st's storage: the result aliases it and
	31	+	// its Window points into its Windows. The placeholder screen is not an
	32	+	// output.
	33	+	func (c *Core) stateInto(st ports.State) ports.State {
	34	+	st.Output, st.Window = c.cur().name(), nil
	35	+	st.Outputs, st.Windows = st.Outputs[:0], st.Windows[:0]
	36	+	if c.scratch.shown == nil {
	37	+	c.scratch.shown = map[WindowID]bool{}
	38	+	}
	39	+	shown := c.scratch.shown
27	40		focus, _ := c.cur().mon.Focused()
28	41		for _, s := range c.screens {
29	42		if s.name() == "" {

@@ -37,7 +50,7 @@ func (c *Core) state() ports.State {
37	50		}
38	51		st.Outputs = append(st.Outputs, o)
39	52		// Visible follows the configures: drawn on the output.
40		-	shown := map[WindowID]bool{}
	53	+	clear(shown)
41	54		// Read at once, into publish's scratch: the snapshot holds no
42	55		// placement.
43	56		c.realBuf = m.layoutInto(c.realBuf)

@@ -46,7 +59,8 @@ func (c *Core) state() ports.State {
46	59		}
47	60		for w := range m.all() {
48	61		n := indexOf(m.Workspaces, w) + 1
49		-	for _, id := range w.windows() {
	62	+	c.scratch.ids = w.appendWindows(c.scratch.ids[:0])
	63	+	for _, id := range c.scratch.ids {
50	64		rec := c.windows.lookup(id)
51	65		v := ports.WindowState{ID: id, AppID: rec.client.AppID, PID: rec.client.PID, Output: s.name(), Workspace: n, WorkspaceID: w.ID, WorkspaceName: w.Name, Visible: shown[id], IdleInhibit: rec.idleInhibit, Floating: w.isFloat(id)}
52	66		if i := w.stashIndex(id); i >= 0 {

@@ -62,13 +76,28 @@ func (c *Core) state() ports.State {
62	76		slices.SortFunc(st.Windows, func(a, b ports.WindowState) int { return cmp.Compare(a.ID, b.ID) })
63	77		for i := range st.Windows {
64	78		if st.Windows[i].ID == focus && focus != 0 {
65		-	w := st.Windows[i]
66		-	st.Window = &w
	79	+	st.Window = &st.Windows[i]
67	80		}
68	81		}
69	82		return st
70	83		}
71	84
	85	+	func sameState(a, b ports.State) bool {
	86	+	return a.Output == b.Output && slices.Equal(a.Outputs, b.Outputs) && slices.Equal(a.Windows, b.Windows) &&
	87	+	(a.Window == nil) == (b.Window == nil) && (a.Window == nil \|\| a.Window == b.Window)
	88	+	}
	89	+
	90	+	// cloneState copies st out of the scratch: empty lists stay non-nil (JSON
	91	+	// []), and Window is its own copy.
	92	+	func cloneState(st ports.State) ports.State {
	93	+	out := ports.State{Output: st.Output, Outputs: append([]ports.OutputState{}, st.Outputs...), Windows: append([]ports.WindowState{}, st.Windows...)}
	94	+	if st.Window != nil {
	95	+	w := *st.Window
	96	+	out.Window = &w
	97	+	}
	98	+	return out
	99	+	}
	100	+
72	101		// numbered counts numbered workspaces, without the trailing spare one
73	102		// unless it is on screen.
74	103		func numbered(m *Monitor) int {


@@ -2,28 +2,41 @@ package core
2			2
3		import (	3		import (
4		"cmp"	4		"cmp"
5	-	"reflect"
6		"slices"	5		"slices"
7			6
8		"github.com/bnema/neferwl/internal/ports"	7		"github.com/bnema/neferwl/internal/ports"
9		)	8		)
10			9
11	-	// publishState sends the script-facing snapshot when it changed.	10	+	// publishState sends the script-facing snapshot when it changed. It is
			11	+	// built in the owner's scratch every publish and copied only when sent: an
			12	+	// animation frame that changes nothing allocates nothing here.
12		func (c *Core) publishState() {	13		func (c *Core) publishState() {
13		if c.ch.State == nil {	14		if c.ch.State == nil {
14		return	15		return
15		}	16		}
16	-	st := c.state()	17	+	c.scratch.state = c.stateInto(c.scratch.state)
17	-	if reflect.DeepEqual(st, c.sent.state) {	18	+	// The first snapshot is always sent, even an empty one.
			19	+	if c.sent.state.Outputs != nil && sameState(c.scratch.state, c.sent.state) {
18		return	20		return
19		}	21		}
			22	+	st := cloneState(c.scratch.state)
20		c.sent.state = st	23		c.sent.state = st
21		latest(c.ch.State, st)	24		latest(c.ch.State, st)
22		}	25		}
23			26
24	-	// state builds the snapshot. The placeholder screen is not an output.	27	+	// state is a fresh snapshot, the caller's to keep.
25	-	func (c *Core) state() ports.State {	28	+	func (c *Core) state() ports.State { return cloneState(c.stateInto(ports.State{})) }
26	-	st := ports.State{Output: c.cur().name(), Outputs: []ports.OutputState{}, Windows: []ports.WindowState{}}	29	+
			30	+	// stateInto builds the snapshot in st's storage: the result aliases it and
			31	+	// its Window points into its Windows. The placeholder screen is not an
			32	+	// output.
			33	+	func (c *Core) stateInto(st ports.State) ports.State {
			34	+	st.Output, st.Window = c.cur().name(), nil
			35	+	st.Outputs, st.Windows = st.Outputs[:0], st.Windows[:0]
			36	+	if c.scratch.shown == nil {
			37	+	c.scratch.shown = map[WindowID]bool{}
			38	+	}
			39	+	shown := c.scratch.shown
27		focus, _ := c.cur().mon.Focused()	40		focus, _ := c.cur().mon.Focused()
28		for _, s := range c.screens {	41		for _, s := range c.screens {
29		if s.name() == "" {	42		if s.name() == "" {

@@ -37,7 +50,7 @@ func (c *Core) state() ports.State {
37		}	50		}
38		st.Outputs = append(st.Outputs, o)	51		st.Outputs = append(st.Outputs, o)
39		// Visible follows the configures: drawn on the output.	52		// Visible follows the configures: drawn on the output.
40	-	shown := map[WindowID]bool{}	53	+	clear(shown)
41		// Read at once, into publish's scratch: the snapshot holds no	54		// Read at once, into publish's scratch: the snapshot holds no
42		// placement.	55		// placement.
43		c.realBuf = m.layoutInto(c.realBuf)	56		c.realBuf = m.layoutInto(c.realBuf)

@@ -46,7 +59,8 @@ func (c *Core) state() ports.State {
46		}	59		}
47		for w := range m.all() {	60		for w := range m.all() {
48		n := indexOf(m.Workspaces, w) + 1	61		n := indexOf(m.Workspaces, w) + 1
49	-	for _, id := range w.windows() {	62	+	c.scratch.ids = w.appendWindows(c.scratch.ids[:0])
			63	+	for _, id := range c.scratch.ids {
50		rec := c.windows.lookup(id)	64		rec := c.windows.lookup(id)
51		v := ports.WindowState{ID: id, AppID: rec.client.AppID, PID: rec.client.PID, Output: s.name(), Workspace: n, WorkspaceID: w.ID, WorkspaceName: w.Name, Visible: shown[id], IdleInhibit: rec.idleInhibit, Floating: w.isFloat(id)}	65		v := ports.WindowState{ID: id, AppID: rec.client.AppID, PID: rec.client.PID, Output: s.name(), Workspace: n, WorkspaceID: w.ID, WorkspaceName: w.Name, Visible: shown[id], IdleInhibit: rec.idleInhibit, Floating: w.isFloat(id)}
52		if i := w.stashIndex(id); i >= 0 {	66		if i := w.stashIndex(id); i >= 0 {

@@ -62,13 +76,28 @@ func (c *Core) state() ports.State {
62		slices.SortFunc(st.Windows, func(a, b ports.WindowState) int { return cmp.Compare(a.ID, b.ID) })	76		slices.SortFunc(st.Windows, func(a, b ports.WindowState) int { return cmp.Compare(a.ID, b.ID) })
63		for i := range st.Windows {	77		for i := range st.Windows {
64		if st.Windows[i].ID == focus && focus != 0 {	78		if st.Windows[i].ID == focus && focus != 0 {
65	-	w := st.Windows[i]	79	+	st.Window = &st.Windows[i]
66	-	st.Window = &w
67		}	80		}
68		}	81		}
69		return st	82		return st
70		}	83		}
71			84
			85	+	func sameState(a, b ports.State) bool {
			86	+	return a.Output == b.Output && slices.Equal(a.Outputs, b.Outputs) && slices.Equal(a.Windows, b.Windows) &&
			87	+	(a.Window == nil) == (b.Window == nil) && (a.Window == nil \|\| a.Window == b.Window)
			88	+	}
			89	+
			90	+	// cloneState copies st out of the scratch: empty lists stay non-nil (JSON
			91	+	// []), and Window is its own copy.
			92	+	func cloneState(st ports.State) ports.State {
			93	+	out := ports.State{Output: st.Output, Outputs: append([]ports.OutputState{}, st.Outputs...), Windows: append([]ports.WindowState{}, st.Windows...)}
			94	+	if st.Window != nil {
			95	+	w := *st.Window
			96	+	out.Window = &w
			97	+	}
			98	+	return out
			99	+	}
			100	+
72		// numbered counts numbered workspaces, without the trailing spare one	101		// numbered counts numbered workspaces, without the trailing spare one
73		// unless it is on screen.	102		// unless it is on screen.
74		func numbered(m *Monitor) int {	103		func numbered(m *Monitor) int {

M internal/core/workspaces.go +25 -5

@@ -1,7 +1,7 @@
1	1		package core
2	2
3	3		import (
4		-	"reflect"
	4	+	"slices"
5	5		"strconv"
6	6
7	7		"github.com/bnema/neferwl/internal/ports"

@@ -10,17 +10,25 @@ import (
10	10		// publishWorkspaces describes the numbered vertical stack and configured hidden
11	11		// workspaces. Config-hidden named workspaces and empty numbered spares are
12	12		// hidden unless shown; unlike State, hidden named workspaces remain addressable.
	13	+	// Like publishState, it is built in the owner's scratch and copied only
	14	+	// when sent.
13	15		func (c *Core) publishWorkspaces() {
14	16		if c.ch.Workspaces == nil {
15	17		return
16	18		}
17		-	snapshot := ports.Workspaces{Outputs: []ports.WorkspaceOutput{}}
	19	+	buf := &c.scratch.workspaces
	20	+	buf.Outputs = buf.Outputs[:0]
18	21		for _, sc := range c.screens {
19	22		if sc.name() == "" {
20	23		continue
21	24		}
22	25		m := sc.mon
23		-	out := ports.WorkspaceOutput{Name: sc.name(), Workspaces: []ports.WorkspaceInfo{}}
	26	+	// Reuse the list of the entry this one overwrites.
	27	+	var list []ports.WorkspaceInfo
	28	+	if n := len(buf.Outputs); n < cap(buf.Outputs) {
	29	+	list = buf.Outputs[:n+1][n].Workspaces[:0]
	30	+	}
	31	+	out := ports.WorkspaceOutput{Name: sc.name(), Workspaces: list}
24	32		i := -1
25	33		for w := range m.all() {
26	34		i++

@@ -30,11 +38,23 @@ func (c *Core) publishWorkspaces() {
30	38		}
31	39		out.Workspaces = append(out.Workspaces, ports.WorkspaceInfo{ID: w.ID, Name: name, Index: i, Active: m.Current() == w, Hidden: m.Current() != w && (m.isHidden(w) \|\| w.empty()), Configured: w.Name, Frame: w.Output})
32	40		}
33		-	snapshot.Outputs = append(snapshot.Outputs, out)
	41	+	buf.Outputs = append(buf.Outputs, out)
34	42		}
35		-	if reflect.DeepEqual(snapshot, c.sent.workspaces) {
	43	+	// The first snapshot is always sent, even an empty one.
	44	+	if c.sent.workspaces.Outputs != nil && sameWorkspaces(*buf, c.sent.workspaces) {
36	45		return
37	46		}
	47	+	// Empty lists stay non-nil (JSON []).
	48	+	snapshot := ports.Workspaces{Outputs: make([]ports.WorkspaceOutput, len(buf.Outputs))}
	49	+	for k, o := range buf.Outputs {
	50	+	snapshot.Outputs[k] = ports.WorkspaceOutput{Name: o.Name, Workspaces: append([]ports.WorkspaceInfo{}, o.Workspaces...)}
	51	+	}
38	52		c.sent.workspaces = snapshot
39	53		latest(c.ch.Workspaces, snapshot)
40	54		}
	55	+
	56	+	func sameWorkspaces(a, b ports.Workspaces) bool {
	57	+	return slices.EqualFunc(a.Outputs, b.Outputs, func(x, y ports.WorkspaceOutput) bool {
	58	+	return x.Name == y.Name && slices.Equal(x.Workspaces, y.Workspaces)
	59	+	})
	60	+	}

 package core
 import (
-	"reflect"
+	"slices"
 	"strconv"
 	"github.com/bnema/neferwl/internal/ports"
 // publishWorkspaces describes the numbered vertical stack and configured hidden
 // workspaces. Config-hidden named workspaces and empty numbered spares are
 // hidden unless shown; unlike State, hidden named workspaces remain addressable.
+// Like publishState, it is built in the owner's scratch and copied only
+// when sent.
 func (c *Core) publishWorkspaces() {
 	if c.ch.Workspaces == nil {
 		return
 	}
-	snapshot := ports.Workspaces{Outputs: []ports.WorkspaceOutput{}}
+	buf := &c.scratch.workspaces
+	buf.Outputs = buf.Outputs[:0]
 	for _, sc := range c.screens {
 		if sc.name() == "" {
 			continue
 		}
 		m := sc.mon
-		out := ports.WorkspaceOutput{Name: sc.name(), Workspaces: []ports.WorkspaceInfo{}}
+		// Reuse the list of the entry this one overwrites.
+		var list []ports.WorkspaceInfo
+		if n := len(buf.Outputs); n < cap(buf.Outputs) {
+			list = buf.Outputs[:n+1][n].Workspaces[:0]
+		}
+		out := ports.WorkspaceOutput{Name: sc.name(), Workspaces: list}
 		i := -1
 		for w := range m.all() {
 			i++
 			}
 			out.Workspaces = append(out.Workspaces, ports.WorkspaceInfo{ID: w.ID, Name: name, Index: i, Active: m.Current() == w, Hidden: m.Current() != w && (m.isHidden(w) || w.empty()), Configured: w.Name, Frame: w.Output})
 		}
-		snapshot.Outputs = append(snapshot.Outputs, out)
+		buf.Outputs = append(buf.Outputs, out)
 	}
-	if reflect.DeepEqual(snapshot, c.sent.workspaces) {
+	// The first snapshot is always sent, even an empty one.
+	if c.sent.workspaces.Outputs != nil && sameWorkspaces(*buf, c.sent.workspaces) {
 		return
 	}
+	// Empty lists stay non-nil (JSON []).
+	snapshot := ports.Workspaces{Outputs: make([]ports.WorkspaceOutput, len(buf.Outputs))}
+	for k, o := range buf.Outputs {
+		snapshot.Outputs[k] = ports.WorkspaceOutput{Name: o.Name, Workspaces: append([]ports.WorkspaceInfo{}, o.Workspaces...)}
+	}
 	c.sent.workspaces = snapshot
 	latest(c.ch.Workspaces, snapshot)
 }
+func sameWorkspaces(a, b ports.Workspaces) bool {
+	return slices.EqualFunc(a.Outputs, b.Outputs, func(x, y ports.WorkspaceOutput) bool {
+		return x.Name == y.Name && slices.Equal(x.Workspaces, y.Workspaces)
+	})
+}