forked from GoogleCloudPlatform/gcsfuse
/
main.go
144 lines (118 loc) · 3.35 KB
/
main.go
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// Copyright 2015 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Create a file, truncate it up to a particular size, then measure the
// throughput of repeatedly overwriting its contents without closing it each
// time. This is intended to measure the CPU efficiency of the file system
// rather than GCS throughput.
package main
import (
"errors"
"flag"
"fmt"
"io/ioutil"
"log"
"os"
"time"
"github.com/googlecloudplatform/gcsfuse/benchmarks/internal/format"
)
var fDir = flag.String("dir", "", "Directory within which to write the file.")
var fDuration = flag.Duration("duration", 10*time.Second, "How long to run.")
var fFileSize = flag.Int64("file_size", 1<<26, "Size of file to use.")
var fWriteSize = flag.Int64("write_size", 1<<20, "Size of each call to write(2).")
////////////////////////////////////////////////////////////////////////
// main logic
////////////////////////////////////////////////////////////////////////
func run() (err error) {
if *fDir == "" {
err = errors.New("You must set --dir.")
return
}
// Create a temporary file.
log.Printf("Creating a temporary file in %s.", *fDir)
f, err := ioutil.TempFile(*fDir, "write_locally")
if err != nil {
err = fmt.Errorf("TempFile: %v", err)
return
}
path := f.Name()
// Make sure we clean it up later.
defer func() {
log.Printf("Truncating and closing %s.", path)
f.Truncate(0)
f.Close()
log.Printf("Deleting %s.", path)
os.Remove(path)
}()
// Extend to the initial size.
log.Printf("Truncating to %d bytes.", *fFileSize)
err = f.Truncate(*fFileSize)
if err != nil {
err = fmt.Errorf("Truncate: %v", err)
return
}
// Repeatedly overwrite the file with zeroes.
log.Println("Measuring...")
var bytesWritten int64
var writeCount int64
buf := make([]byte, *fWriteSize)
start := time.Now()
for time.Since(start) < *fDuration {
// Seek to the beginning.
_, err = f.Seek(0, 0)
if err != nil {
err = fmt.Errorf("Seek: %v", err)
return
}
// Overwrite.
var n int64
for n < *fFileSize && time.Since(start) < *fDuration {
toWrite := *fFileSize - n
if toWrite > *fWriteSize {
toWrite = *fWriteSize
}
var tmp int
tmp, err = f.Write(buf)
if err != nil {
err = fmt.Errorf("Write: %v", err)
return
}
n += int64(tmp)
bytesWritten += int64(tmp)
writeCount++
}
}
d := time.Since(start)
// Report.
seconds := float64(d) / float64(time.Second)
writesPerSec := float64(writeCount) / seconds
bytesPerSec := float64(bytesWritten) / seconds
fmt.Printf(
"Wrote %d times (%s) in %v (%.1f Hz, %s/s)\n",
writeCount,
format.Bytes(float64(bytesWritten)),
d,
writesPerSec,
format.Bytes(bytesPerSec))
fmt.Println()
return
}
func main() {
log.SetFlags(log.Lmicroseconds | log.Lshortfile)
flag.Parse()
err := run()
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
}