mirror of
https://github.com/shadow1ng/fscan.git
synced 2026-09-22 03:10:42 +08:00
ZacharyZcR
7063027acf
- port_scan: fmt.Sprintf→JoinHostPort+fmtPort零分配地址格式化 (2.5x) - port_scan: strings.ToLower→containsFold零分配大小写不敏感匹配 (2.5x) - port_scan: slidingWindowSchedule修复semaphore泄漏bug - service_probe: readFromConn预分配4KB缓冲区消除扩容 - adaptive_pool: maybeAdjust用atomic CAS代替持锁检查, 99%免锁 - adaptive_timeout: Timeout锁外计算均值/标准差, 只锁缓存更新 - 新增perf_bench_test.go基准测试验证所有优化
111 lines
2.3 KiB
Go
111 lines
2.3 KiB
Go
package core
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import (
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"math"
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"sync"
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"time"
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)
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// AdaptiveTimeout 基于 RTT 采样的自适应超时计算器
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// 算法：timeout = mean(RTT) + 4 * stddev(RTT)，clamp 到 [min, max]
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// 冷启动阶段（样本不足）返回用户配置的固定超时
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type AdaptiveTimeout struct {
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mu sync.Mutex
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samples []float64 // 环形缓冲区，单位 ms
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pos int // 写入位置
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count int // 已采集总数
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size int // 缓冲区容量
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minTO time.Duration
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maxTO time.Duration
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warmup int // 冷启动所需最小样本数
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cachedTO time.Duration
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dirty bool
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}
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// NewAdaptiveTimeout 创建自适应超时计算器
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// maxTimeout: 用户配置的超时上限（即原始固定超时）
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func NewAdaptiveTimeout(maxTimeout time.Duration) *AdaptiveTimeout {
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return &AdaptiveTimeout{
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samples: make([]float64, 64),
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size: 64,
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minTO: 100 * time.Millisecond,
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maxTO: maxTimeout,
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warmup: 10,
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}
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}
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// Record 记录一次成功连接的 RTT
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func (a *AdaptiveTimeout) Record(rtt time.Duration) {
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a.mu.Lock()
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a.samples[a.pos%a.size] = float64(rtt.Milliseconds())
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a.pos++
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a.count++
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a.dirty = true
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a.mu.Unlock()
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}
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// Timeout 获取当前推荐超时值
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// 样本不足时返回 maxTO（冷启动）
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// 锁外执行均值/标准差计算，减少锁持有时间
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func (a *AdaptiveTimeout) Timeout() time.Duration {
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a.mu.Lock()
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if a.count < a.warmup {
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a.mu.Unlock()
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return a.maxTO
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}
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if !a.dirty {
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cached := a.cachedTO
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a.mu.Unlock()
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return cached
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}
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n := a.size
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if a.count < a.size {
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n = a.count
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}
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// 拷贝样本到本地，释放锁后再计算
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localSamples := make([]float64, n)
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start := a.pos % a.size
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if a.count < a.size {
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copy(localSamples, a.samples[:n])
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} else {
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copy(localSamples[:a.size-start], a.samples[start:])
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copy(localSamples[a.size-start:], a.samples[:start])
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}
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a.mu.Unlock()
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// 锁外计算
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var sum float64
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for _, s := range localSamples {
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sum += s
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}
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mean := sum / float64(n)
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var variance float64
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for _, s := range localSamples {
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d := s - mean
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variance += d * d
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}
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stddev := math.Sqrt(variance / float64(n))
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ms := mean + 4*stddev
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to := time.Duration(ms) * time.Millisecond
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if to < a.minTO {
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to = a.minTO
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}
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if to > a.maxTO {
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to = a.maxTO
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}
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// 短暂加锁更新缓存
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a.mu.Lock()
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a.cachedTO = to
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a.dirty = false
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a.mu.Unlock()
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return to
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}
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