storage_tuning_test.go RawHistoryFolder

1package vt
2
3import (
4	"fmt"
5	"runtime"
6	"testing"
7
8	"github.com/bnema/vev-vt/core"
9)
10
11func TestHistoryTailPreallocationFollowsGeometry(t *testing.T) {
12	h := NewHistory(HistoryConfig{MaxRows: 4, MaxBytes: 1 << 20, ChunkRows: 4})
13	if err := h.Append(historyRow("abc"), LineBound{End: 3}); err != nil {
14		t.Fatal(err)
15	}
16	if got := cap(h.tailCells); got > 12 {
17		t.Fatalf("tail preallocation = %d cells, want at most 4x3", got)
18	}
19}
20
21func BenchmarkHistoryChunkSize(b *testing.B) {
22	for _, rows := range []int{32, 64, 128, 256} {
23		b.Run(fmt.Sprintf("rows-%d", rows), func(b *testing.B) {
24			b.ReportAllocs()
25			for b.Loop() {
26				h := NewHistory(HistoryConfig{MaxRows: 10_000, MaxBytes: 1 << 30, ChunkRows: rows})
27				row := make([]core.Cell, 120)
28				for x := range row {
29					row[x] = core.Cell{Rune: rune('a' + x%26), Style: core.DefaultStyle()}
30				}
31				for range 10_000 {
32					if err := h.Append(row, LineBound{End: 120}); err != nil {
33						b.Fatal(err)
34					}
35				}
36				benchmarkStorageHistorySink = h
37			}
38		})
39	}
40}
41
42func BenchmarkSmallHistoryRetained(b *testing.B) {
43	var retained uint64
44	for b.Loop() {
45		benchmarkStorageHistorySink = nil
46		runtime.GC()
47		var before, after runtime.MemStats
48		runtime.ReadMemStats(&before)
49		h := NewHistory(HistoryConfig{MaxRows: 4, MaxBytes: 1 << 20, ChunkRows: 4})
50		if err := h.Append(historyRow("abc"), LineBound{End: 3}); err != nil {
51			b.Fatal(err)
52		}
53		benchmarkStorageHistorySink = h
54		runtime.GC()
55		runtime.ReadMemStats(&after)
56		if after.HeapAlloc >= before.HeapAlloc {
57			retained += after.HeapAlloc - before.HeapAlloc
58		}
59	}
60	b.ReportMetric(float64(retained)/float64(b.N), "retained-B/op")
61}