Use a buffer pool in report.ReadBinary() to reduce garbage-collection

report/marshal.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/ugorji/go/codec"
@@ -61,13 +62,18 @@ func (c byteCounter) Read(p []byte) (n int, err error) {
 	return n, err
 }
 
+// buffer pool to reduce garbage-collection
+var bufferPool = &sync.Pool{
+	New: func() interface{} { return new(bytes.Buffer) },
+}
+
 // ReadBinary reads bytes into a Report.
 //
 // Will decompress the binary if gzipped is true, and will use the given
 // codecHandle to decode it.
 func (rep *Report) ReadBinary(r io.Reader, gzipped bool, codecHandle codec.Handle) error {
 	var err error
-	var compressedSize, uncompressedSize uint64
+	var compressedSize uint64
 
 	// We have historically had trouble with reports being too large. We are
 	// keeping this instrumentation around to help us implement
@@ -82,12 +88,14 @@ func (rep *Report) ReadBinary(r io.Reader, gzipped bool, codecHandle codec.Handl
 		}
 	}
 	// Read everything into memory before decoding: it's faster
-	buf, err := ioutil.ReadAll(r)
+	buf := bufferPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	defer bufferPool.Put(buf)
+	uncompressedSize, err := buf.ReadFrom(r)
 	if err != nil {
 		return err
 	}
-	uncompressedSize = uint64(len(buf))
-	if err := rep.ReadBytes(buf, codecHandle); err != nil {
+	if err := rep.ReadBytes(buf.Bytes(), codecHandle); err != nil {
 		return err
 	}
 	log.Debugf(