all: improve ETA calculation across all progress indicators (#32521)

### Summary
Fixes long-standing ETA calculation errors in progress indicators that
have been present since February 2021. The current implementation
produces increasingly inaccurate estimates due to integer division
precision loss.

### Problem

3aeccadd04/triedb/pathdb/history_indexer.go (L541-L553)
The ETA calculation has two critical issues:
1. **Integer division precision loss**: `speed` is calculated as
`uint64`
2. **Off-by-one**: `speed` uses `+ 1`(2 times) to avoid division by
zero, however it makes mistake in the final calculation

This results in wildly inaccurate time estimates that don't improve as
progress continues.

### Example
Current output during state history indexing:
```
lvl=info msg="Indexing state history" processed=16858580 left=41802252 elapsed=18h22m59.848s eta=11h36m42.252s
```

**Expected calculation:**
- Speed: 16858580 ÷ 66179848ms = 0.255 blocks/ms  
- ETA: 41802252 ÷ 0.255 = ~45.6 hours

**Current buggy calculation:**
- Speed: rounds to 1 block/ms
- ETA: 41802252 ÷ 1 = ~11.6 hours ❌

### Solution
- Created centralized `CalculateETA()` function in common package
- Replaced all 8 duplicate code copies across the codebase

### Testing
Verified accurate ETA calculations during archive node reindexing with
significantly improved time estimates.

common/eta.go

@@ -0,0 +1,30 @@
+// Copyright 2025 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package common
+
+import "time"
+
+// CalculateETA calculates the estimated remaining time based on the
+// number of finished task, remaining task, and the time cost for finished task.
+func CalculateETA(done, left uint64, elapsed time.Duration) time.Duration {
+	if done == 0 || elapsed.Milliseconds() == 0 {
+		return 0
+	}
+
+	speed := float64(done) / float64(elapsed.Milliseconds())
+	return time.Duration(float64(left)/speed) * time.Millisecond
+}

common/eta_test.go

@@ -0,0 +1,60 @@
+// Copyright 2025 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package common
+
+import (
+	"testing"
+	"time"
+)
+
+func TestCalculateETA(t *testing.T) {
+	type args struct {
+		done    uint64
+		left    uint64
+		elapsed time.Duration
+	}
+	tests := []struct {
+		name string
+		args args
+		want time.Duration
+	}{
+		{
+			name: "zero done",
+			args: args{done: 0, left: 100, elapsed: time.Second},
+			want: 0,
+		},
+		{
+			name: "zero elapsed",
+			args: args{done: 1, left: 100, elapsed: 0},
+			want: 0,
+		},
+		{
+			name: "@Jolly23 's case",
+			args: args{done: 16858580, left: 41802252, elapsed: 66179848 * time.Millisecond},
+			want: 164098440 * time.Millisecond,
+			// wrong msg: msg="Indexing state history" processed=16858580 left=41802252 elapsed=18h22m59.848s eta=11h36m42.252s
+			// should be around 45.58 hours
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := CalculateETA(tt.args.done, tt.args.left, tt.args.elapsed); got != tt.want {
+				t.Errorf("CalculateETA() = %v ms, want %v ms", got.Milliseconds(), tt.want)
+			}
+		})
+	}
+}

core/state/pruner/pruner.go

@@ -160,11 +160,8 @@ func prune(snaptree *snapshot.Tree, root common.Hash, maindb ethdb.Database, sta
 
 			var eta time.Duration // Realistically will never remain uninited
 			if done := binary.BigEndian.Uint64(key[:8]); done > 0 {
-				var (
-					left  = math.MaxUint64 - binary.BigEndian.Uint64(key[:8])
-					speed = done/uint64(time.Since(pstart)/time.Millisecond+1) + 1 // +1s to avoid division by zero
-				)
-				eta = time.Duration(left/speed) * time.Millisecond
+				left := math.MaxUint64 - binary.BigEndian.Uint64(key[:8])
+				eta = common.CalculateETA(done, left, time.Since(pstart))
 			}
 			if time.Since(logged) > 8*time.Second {
 				log.Info("Pruning state data", "nodes", count, "skipped", skipped, "size", size,

core/state/snapshot/conversion.go

@@ -171,20 +171,16 @@ func (stat *generateStats) report() {
 		// If there's progress on the account trie, estimate the time to finish crawling it
 		if done := binary.BigEndian.Uint64(stat.head[:8]) / stat.accounts; done > 0 {
 			var (
-				left  = (math.MaxUint64 - binary.BigEndian.Uint64(stat.head[:8])) / stat.accounts
-				speed = done/uint64(time.Since(stat.start)/time.Millisecond+1) + 1 // +1s to avoid division by zero
-				eta   = time.Duration(left/speed) * time.Millisecond
+				left = (math.MaxUint64 - binary.BigEndian.Uint64(stat.head[:8])) / stat.accounts
+				eta  = common.CalculateETA(done, left, time.Since(stat.start))
 			)
 			// If there are large contract crawls in progress, estimate their finish time
 			for acc, head := range stat.slotsHead {
 				start := stat.slotsStart[acc]
 				if done := binary.BigEndian.Uint64(head[:8]); done > 0 {
-					var (
-						left  = math.MaxUint64 - binary.BigEndian.Uint64(head[:8])
-						speed = done/uint64(time.Since(start)/time.Millisecond+1) + 1 // +1s to avoid division by zero
-					)
+					left := math.MaxUint64 - binary.BigEndian.Uint64(head[:8])
 					// Override the ETA if larger than the largest until now
-					if slotETA := time.Duration(left/speed) * time.Millisecond; eta < slotETA {
+					if slotETA := common.CalculateETA(done, left, time.Since(start)); eta < slotETA {
 						eta = slotETA
 					}
 				}

triedb/pathdb/history_indexer.go

@@ -543,12 +543,10 @@ func (i *indexIniter) index(done chan struct{}, interrupt *atomic.Int32, lastID
 				logged = time.Now()
 
 				var (
-					left  = lastID - current + 1
-					done  = current - beginID
-					speed = done/uint64(time.Since(start)/time.Millisecond+1) + 1 // +1s to avoid division by zero
+					left = lastID - current + 1
+					done = current - beginID
 				)
-				// Override the ETA if larger than the largest until now
-				eta := time.Duration(left/speed) * time.Millisecond
+				eta := common.CalculateETA(done, left, time.Since(start))
 				log.Info("Indexing state history", "processed", done, "left", left, "elapsed", common.PrettyDuration(time.Since(start)), "eta", common.PrettyDuration(eta))
 			}
 		}

triedb/pathdb/verifier.go

@@ -166,20 +166,17 @@ func (stat *generateStats) report() {
 		// If there's progress on the account trie, estimate the time to finish crawling it
 		if done := binary.BigEndian.Uint64(stat.head[:8]) / stat.accounts; done > 0 {
 			var (
-				left  = (math.MaxUint64 - binary.BigEndian.Uint64(stat.head[:8])) / stat.accounts
-				speed = done/uint64(time.Since(stat.start)/time.Millisecond+1) + 1 // +1s to avoid division by zero
-				eta   = time.Duration(left/speed) * time.Millisecond
+				left = (math.MaxUint64 - binary.BigEndian.Uint64(stat.head[:8])) / stat.accounts
+				eta  = common.CalculateETA(done, left, time.Since(stat.start))
 			)
 			// If there are large contract crawls in progress, estimate their finish time
 			for acc, head := range stat.slotsHead {
 				start := stat.slotsStart[acc]
 				if done := binary.BigEndian.Uint64(head[:8]); done > 0 {
-					var (
-						left  = math.MaxUint64 - binary.BigEndian.Uint64(head[:8])
-						speed = done/uint64(time.Since(start)/time.Millisecond+1) + 1 // +1s to avoid division by zero
-					)
+					left := math.MaxUint64 - binary.BigEndian.Uint64(head[:8])
+
 					// Override the ETA if larger than the largest until now
-					if slotETA := time.Duration(left/speed) * time.Millisecond; eta < slotETA {
+					if slotETA := common.CalculateETA(done, left, time.Since(start)); eta < slotETA {
 						eta = slotETA
 					}
 				}