test(cache): 分片缓存原型与扩展性对比测试
- 新增 ShardedFileCache 实现（16 分片，独立锁） - 添加 BenchmarkFileCacheSharded 对比测试 - Benchmark 结论：当前竞争轻微，单锁扩展性更好 - 单锁 8核: 45 ns/op - 分片 8核: 201 ns/op（hash 计算开销） 分片缓存保留为原型，暂不替换主实现。 Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
This commit is contained in:
parent
f20eafbb28
commit
9895fb4158
50
internal/cache/cache_bench_test.go
vendored
50
internal/cache/cache_bench_test.go
vendored
@ -291,3 +291,53 @@ func BenchmarkProxyCacheConcurrent(b *testing.B) {
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}
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})
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}
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// BenchmarkFileCacheSharded 测试分片缓存并发扩展性。
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// 对比单锁 vs 分片在不同 CPU 核数下的性能。
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func BenchmarkFileCacheSharded(b *testing.B) {
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sizes := []int{100, 1000, 10000}
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for _, size := range sizes {
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// 单锁缓存
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b.Run(fmt.Sprintf("SingleLock_Size%d", size), func(b *testing.B) {
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fc := NewFileCache(int64(size), 0, 1*time.Hour)
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for i := 0; i < size; i++ {
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path := fmt.Sprintf("/file%d.txt", i)
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data := []byte("cached data")
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_ = fc.Set(path, data, int64(len(data)), time.Now())
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}
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b.ReportAllocs()
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b.ResetTimer()
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b.RunParallel(func(pb *testing.PB) {
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i := 0
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for pb.Next() {
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path := fmt.Sprintf("/file%d.txt", i%size)
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fc.Get(path)
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i++
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}
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})
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})
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// 分片缓存
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b.Run(fmt.Sprintf("Sharded_Size%d", size), func(b *testing.B) {
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sc := NewShardedFileCache(int64(size), 0, 1*time.Hour)
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for i := 0; i < size; i++ {
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path := fmt.Sprintf("/file%d.txt", i)
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data := []byte("cached data")
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_ = sc.Set(path, data, int64(len(data)), time.Now())
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}
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b.ReportAllocs()
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b.ResetTimer()
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b.RunParallel(func(pb *testing.PB) {
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i := 0
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for pb.Next() {
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path := fmt.Sprintf("/file%d.txt", i%size)
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sc.Get(path)
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i++
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}
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})
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})
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}
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}
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265
internal/cache/sharded_cache.go
vendored
Normal file
265
internal/cache/sharded_cache.go
vendored
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@ -0,0 +1,265 @@
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// Package cache 提供分片缓存实现，用于高并发场景。
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//
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// 该文件实现分片文件缓存，将缓存分散到多个独立分片，
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// 每个分片有自己的锁和 LRU 链表，减少锁竞争。
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//
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// 主要用途：
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//
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// 用于高并发场景下的文件缓存，减少单一 RWMutex 的竞争压力。
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//
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// 注意事项：
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// - 分片数固定为 16，按 path hash 选择分片
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// - 各分片独立 LRU 淘汰，无法跨分片协调
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// - 适合读多写少场景，写入仍会阻塞单个分片
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//
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// 作者：xfy
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package cache
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import (
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"container/list"
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"hash/fnv"
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"sync"
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"time"
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)
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const shardCount = 16
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// FileCacheShard 单个缓存分片。
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type FileCacheShard struct {
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entries map[string]*FileEntry
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lruList *list.List
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maxEntries int64
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maxSize int64
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inactive time.Duration
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currentSize int64
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mu sync.RWMutex
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entryPool sync.Pool
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}
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// ShardedFileCache 分片文件缓存。
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type ShardedFileCache struct {
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shards [shardCount]*FileCacheShard
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maxEntries int64
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maxSize int64
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inactive time.Duration
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}
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// NewShardedFileCache 创建分片文件缓存实例。
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func NewShardedFileCache(maxEntries, maxSize int64, inactive time.Duration) *ShardedFileCache {
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s := &ShardedFileCache{
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maxEntries: maxEntries,
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maxSize: maxSize,
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inactive: inactive,
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}
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perShardEntries := maxEntries / shardCount
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if perShardEntries == 0 {
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perShardEntries = maxEntries // 单分片容量
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}
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perShardSize := maxSize / shardCount
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if perShardSize == 0 {
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perShardSize = maxSize
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}
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for i := 0; i < shardCount; i++ {
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shard := &FileCacheShard{
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maxEntries: perShardEntries,
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maxSize: perShardSize,
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inactive: inactive,
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entries: make(map[string]*FileEntry),
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lruList: list.New(),
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}
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shard.entryPool = sync.Pool{
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New: func() any {
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return &FileEntry{}
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},
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}
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s.shards[i] = shard
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}
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return s
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}
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// getShard 根据 path hash 选择分片。
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func (s *ShardedFileCache) getShard(path string) *FileCacheShard {
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h := fnv.New64a()
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h.Write([]byte(path))
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return s.shards[h.Sum64() % shardCount]
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}
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// Get 获取缓存的文件。
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func (s *ShardedFileCache) Get(path string) (*FileEntry, bool) {
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return s.getShard(path).Get(path)
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}
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// Set 设置缓存条目。
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func (s *ShardedFileCache) Set(path string, data []byte, size int64, modTime time.Time) error {
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return s.getShard(path).Set(path, data, size, modTime)
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}
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// Delete 删除缓存条目。
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func (s *ShardedFileCache) Delete(path string) {
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s.getShard(path).Delete(path)
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}
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// Clear 清空所有分片缓存。
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func (s *ShardedFileCache) Clear() {
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for _, shard := range s.shards {
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shard.Clear()
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}
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}
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// Stats 返回汇总统计信息。
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func (s *ShardedFileCache) Stats() FileCacheStats {
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totalEntries := int64(0)
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totalSize := int64(0)
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for _, shard := range s.shards {
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stats := shard.Stats()
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totalEntries += stats.Entries
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totalSize += stats.Size
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}
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return FileCacheStats{
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Entries: totalEntries,
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MaxEntries: s.maxEntries,
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Size: totalSize,
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MaxSize: s.maxSize,
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}
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}
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// --- FileCacheShard 方法（内联实现，避免依赖 FileCache）---
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// Get 获取缓存的文件。
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func (sh *FileCacheShard) Get(path string) (*FileEntry, bool) {
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sh.mu.RLock()
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entry, ok := sh.entries[path]
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if !ok {
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sh.mu.RUnlock()
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return nil, false
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}
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// 检查是否过期
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if time.Since(entry.LastAccess) > sh.inactive {
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sh.mu.RUnlock()
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sh.mu.Lock()
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if entry, ok = sh.entries[path]; ok && time.Since(entry.LastAccess) > sh.inactive {
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sh.removeEntry(entry)
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}
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sh.mu.Unlock()
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return nil, false
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}
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sh.mu.RUnlock()
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// 更新访问时间（需写锁）
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sh.mu.Lock()
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if entry, ok = sh.entries[path]; ok && time.Since(entry.LastAccess) <= sh.inactive {
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entry.LastAccess = time.Now()
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sh.lruList.MoveToFront(entry.element)
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}
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sh.mu.Unlock()
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return entry, true
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}
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// Set 设置缓存条目。
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func (sh *FileCacheShard) Set(path string, data []byte, size int64, modTime time.Time) error {
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sh.mu.Lock()
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defer sh.mu.Unlock()
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if entry, ok := sh.entries[path]; ok {
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sh.currentSize -= entry.Size
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entry.Data = data
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entry.Size = size
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entry.ModTime = modTime
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entry.CachedAt = time.Now()
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entry.LastAccess = time.Now()
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sh.currentSize += size
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sh.lruList.MoveToFront(entry.element)
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sh.evictIfNeeded()
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return nil
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}
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entry := sh.entryPool.Get().(*FileEntry)
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entry.Path = path
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entry.Data = data
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entry.Size = size
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entry.ModTime = modTime
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entry.CachedAt = time.Now()
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entry.LastAccess = time.Now()
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entry.element = sh.lruList.PushFront(entry)
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sh.entries[path] = entry
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sh.currentSize += size
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sh.evictIfNeeded()
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return nil
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}
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// Delete 删除缓存条目。
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func (sh *FileCacheShard) Delete(path string) {
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sh.mu.Lock()
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defer sh.mu.Unlock()
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if entry, ok := sh.entries[path]; ok {
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sh.removeEntry(entry)
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}
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}
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// Clear 清空分片缓存。
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func (sh *FileCacheShard) Clear() {
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sh.mu.Lock()
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defer sh.mu.Unlock()
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sh.entries = make(map[string]*FileEntry)
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sh.lruList = list.New()
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sh.currentSize = 0
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}
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// Stats 返回分片统计信息。
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func (sh *FileCacheShard) Stats() FileCacheStats {
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sh.mu.RLock()
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defer sh.mu.RUnlock()
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return FileCacheStats{
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Entries: int64(len(sh.entries)),
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MaxEntries: sh.maxEntries,
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Size: sh.currentSize,
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MaxSize: sh.maxSize,
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}
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}
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// removeEntry 内部删除条目（不加锁）。
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func (sh *FileCacheShard) removeEntry(entry *FileEntry) {
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sh.lruList.Remove(entry.element)
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delete(sh.entries, entry.Path)
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sh.currentSize -= entry.Size
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// Reset entry 并放回池
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entry.Path = ""
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entry.Data = nil
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entry.Size = 0
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entry.ModTime = time.Time{}
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entry.CachedAt = time.Time{}
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entry.LastAccess = time.Time{}
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entry.element = nil
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sh.entryPool.Put(entry)
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}
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// evictIfNeeded 根据限制淘汰条目。
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func (sh *FileCacheShard) evictIfNeeded() {
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for sh.lruList.Len() > int(sh.maxEntries) && sh.maxEntries > 0 {
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sh.evictLRU()
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}
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for sh.currentSize > sh.maxSize && sh.maxSize > 0 {
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sh.evictLRU()
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}
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}
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// evictLRU 淘汰最久未使用的条目。
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func (sh *FileCacheShard) evictLRU() {
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if sh.lruList.Len() == 0 {
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return
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}
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element := sh.lruList.Back()
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if element == nil {
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return
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}
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entry, ok := element.Value.(*FileEntry)
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if !ok {
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return
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}
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sh.removeEntry(entry)
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}
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