overdue

.rclone_repo/cmd/mount/test/seekers.go

@@ -0,0 +1,129 @@
+// +build ignore
+
+// Read lots files with lots of simultaneous seeking to stress test the seek code
+package main
+
+import (
+	"flag"
+	"io"
+	"log"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"sort"
+	"sync"
+	"time"
+)
+
+var (
+	// Flags
+	iterations   = flag.Int("n", 1E6, "Iterations to try")
+	maxBlockSize = flag.Int("b", 1024*1024, "Max block size to read")
+	simultaneous = flag.Int("transfers", 16, "Number of simultaneous files to open")
+	seeksPerFile = flag.Int("seeks", 8, "Seeks per file")
+	mask         = flag.Int64("mask", 0, "mask for seek, eg 0x7fff")
+)
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+func seekTest(n int, file string) {
+	in, err := os.Open(file)
+	if err != nil {
+		log.Fatalf("Couldn't open %q: %v", file, err)
+	}
+	fi, err := in.Stat()
+	if err != nil {
+		log.Fatalf("Couldn't stat %q: %v", file, err)
+	}
+	size := fi.Size()
+
+	// FIXME make sure we try start and end
+
+	maxBlockSize := *maxBlockSize
+	if int64(maxBlockSize) > size {
+		maxBlockSize = int(size)
+	}
+	for i := 0; i < n; i++ {
+		start := rand.Int63n(size)
+		if *mask != 0 {
+			start &^= *mask
+		}
+		blockSize := rand.Intn(maxBlockSize)
+		beyondEnd := false
+		switch rand.Intn(10) {
+		case 0:
+			start = 0
+		case 1:
+			start = size - int64(blockSize)
+		case 2:
+			// seek beyond the end
+			start = size + int64(blockSize)
+			beyondEnd = true
+		default:
+		}
+		if !beyondEnd && int64(blockSize) > size-start {
+			blockSize = int(size - start)
+		}
+		log.Printf("%s: Reading %d from %d", file, blockSize, start)
+
+		_, err = in.Seek(start, io.SeekStart)
+		if err != nil {
+			log.Fatalf("Seek failed on %q: %v", file, err)
+		}
+
+		buf := make([]byte, blockSize)
+		n, err := io.ReadFull(in, buf)
+		if beyondEnd && err == io.EOF {
+			// OK
+		} else if err != nil {
+			log.Fatalf("Read failed on %q: %v (%d)", file, err, n)
+		}
+	}
+
+	err = in.Close()
+	if err != nil {
+		log.Fatalf("Error closing %q: %v", file, err)
+	}
+}
+
+// Find all the files in dir
+func findFiles(dir string) (files []string) {
+	filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if info.Mode().IsRegular() && info.Size() > 0 {
+			files = append(files, path)
+		}
+		return nil
+	})
+	sort.Strings(files)
+	return files
+}
+
+func main() {
+	flag.Parse()
+	args := flag.Args()
+	if len(args) != 1 {
+		log.Fatalf("Require a directory as argument")
+	}
+	dir := args[0]
+	files := findFiles(dir)
+	jobs := make(chan string, *simultaneous)
+	var wg sync.WaitGroup
+	wg.Add(*simultaneous)
+	for i := 0; i < *simultaneous; i++ {
+		go func() {
+			defer wg.Done()
+			for file := range jobs {
+				seekTest(*seeksPerFile, file)
+			}
+		}()
+	}
+	for i := 0; i < *iterations; i++ {
+		i := rand.Intn(len(files))
+		jobs <- files[i]
+		//jobs <- files[i]
+	}
+	close(jobs)
+	wg.Wait()
+}