fix auth-required not sending immediate challenge, benchmark leak

cmd/benchmark/latency_recorder.go

@@ -0,0 +1,173 @@
+package main
+
+import (
+	"bufio"
+	"encoding/binary"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"sync"
+	"time"
+)
+
+// LatencyRecorder writes latency measurements to disk to avoid memory bloat
+type LatencyRecorder struct {
+	file   *os.File
+	writer *bufio.Writer
+	mu     sync.Mutex
+	count  int64
+}
+
+// LatencyStats contains calculated latency statistics
+type LatencyStats struct {
+	Avg        time.Duration
+	P90        time.Duration
+	P95        time.Duration
+	P99        time.Duration
+	Bottom10   time.Duration
+	Count      int64
+}
+
+// NewLatencyRecorder creates a new latency recorder that writes to disk
+func NewLatencyRecorder(baseDir string, testName string) (*LatencyRecorder, error) {
+	latencyFile := filepath.Join(baseDir, fmt.Sprintf("latency_%s.bin", testName))
+	f, err := os.Create(latencyFile)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create latency file: %w", err)
+	}
+
+	return &LatencyRecorder{
+		file:   f,
+		writer: bufio.NewWriter(f),
+		count:  0,
+	}, nil
+}
+
+// Record writes a latency measurement to disk (8 bytes per measurement)
+func (lr *LatencyRecorder) Record(latency time.Duration) error {
+	lr.mu.Lock()
+	defer lr.mu.Unlock()
+
+	// Write latency as 8-byte value (int64 nanoseconds)
+	buf := make([]byte, 8)
+	binary.LittleEndian.PutUint64(buf, uint64(latency.Nanoseconds()))
+
+	if _, err := lr.writer.Write(buf); err != nil {
+		return fmt.Errorf("failed to write latency: %w", err)
+	}
+
+	lr.count++
+	return nil
+}
+
+// Close flushes and closes the latency file
+func (lr *LatencyRecorder) Close() error {
+	lr.mu.Lock()
+	defer lr.mu.Unlock()
+
+	if err := lr.writer.Flush(); err != nil {
+		return fmt.Errorf("failed to flush latency file: %w", err)
+	}
+
+	if err := lr.file.Close(); err != nil {
+		return fmt.Errorf("failed to close latency file: %w", err)
+	}
+
+	return nil
+}
+
+// CalculateStats reads all latencies from disk, sorts them, and calculates statistics
+// This is done on-demand to avoid keeping all latencies in memory during the test
+func (lr *LatencyRecorder) CalculateStats() (*LatencyStats, error) {
+	lr.mu.Lock()
+	filePath := lr.file.Name()
+	count := lr.count
+	lr.mu.Unlock()
+
+	// If no measurements, return zeros
+	if count == 0 {
+		return &LatencyStats{
+			Avg:        0,
+			P90:        0,
+			P95:        0,
+			P99:        0,
+			Bottom10:   0,
+			Count:      0,
+		}, nil
+	}
+
+	// Open file for reading
+	f, err := os.Open(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open latency file for reading: %w", err)
+	}
+	defer f.Close()
+
+	// Read all latencies into memory temporarily for sorting
+	latencies := make([]time.Duration, 0, count)
+	buf := make([]byte, 8)
+	reader := bufio.NewReader(f)
+
+	for {
+		n, err := reader.Read(buf)
+		if err != nil {
+			if err.Error() == "EOF" {
+				break
+			}
+			return nil, fmt.Errorf("failed to read latency data: %w", err)
+		}
+		if n != 8 {
+			break
+		}
+
+		nanos := binary.LittleEndian.Uint64(buf)
+		latencies = append(latencies, time.Duration(nanos))
+	}
+
+	// Check if we actually got any latencies
+	if len(latencies) == 0 {
+		return &LatencyStats{
+			Avg:        0,
+			P90:        0,
+			P95:        0,
+			P99:        0,
+			Bottom10:   0,
+			Count:      0,
+		}, nil
+	}
+
+	// Sort for percentile calculation
+	sort.Slice(latencies, func(i, j int) bool {
+		return latencies[i] < latencies[j]
+	})
+
+	// Calculate statistics
+	stats := &LatencyStats{
+		Count: int64(len(latencies)),
+	}
+
+	// Average
+	var sum time.Duration
+	for _, lat := range latencies {
+		sum += lat
+	}
+	stats.Avg = sum / time.Duration(len(latencies))
+
+	// Percentiles
+	stats.P90 = latencies[int(float64(len(latencies))*0.90)]
+	stats.P95 = latencies[int(float64(len(latencies))*0.95)]
+	stats.P99 = latencies[int(float64(len(latencies))*0.99)]
+
+	// Bottom 10% average
+	bottom10Count := int(float64(len(latencies)) * 0.10)
+	if bottom10Count > 0 {
+		var bottom10Sum time.Duration
+		for i := 0; i < bottom10Count; i++ {
+			bottom10Sum += latencies[i]
+		}
+		stats.Bottom10 = bottom10Sum / time.Duration(bottom10Count)
+	}
+
+	return stats, nil
+}