Update libcontainer for new net stats patch that uses less CPU.

Godeps/Godeps.json

@@ -55,8 +55,8 @@
 		},
 		{
 			"ImportPath": "github.com/docker/libcontainer",
-			"Comment": "v1.2.0-94-g342b086",
+			"Comment": "v1.2.0-99-gfe3801c",
-			"Rev": "342b0860fa8ad4e6feac1581fa86f03c9cb5803d"
+			"Rev": "fe3801ccd2f5d0cc3ec5d063067fc4a1c312fa81"
 		},
 		{
 			"ImportPath": "github.com/fsouza/go-dockerclient",

Godeps/_workspace/src/github.com/docker/libcontainer/README.md

@@ -56,7 +56,7 @@ Docs released under Creative commons.
 
 First of all, please familiarise yourself with the [libcontainer Principles](PRINCIPLES.md).
 
-If you're a *contributor* or aspiring contributor, you should read the [Contributors' Guide](CONTRIBUTORS_GUIDE.md).
+If you're a *contributor* or aspiring contributor, you should read the [Contributors' Guide](CONTRIBUTING.md).
 
 If you're a *maintainer* or aspiring maintainer, you should read the [Maintainers' Guide](MAINTAINERS_GUIDE.md) and
 "How can I become a maintainer?" in the Contributors' Guide.

Godeps/_workspace/src/github.com/docker/libcontainer/cgroups/fs/blkio_test.go

@@ -223,6 +223,9 @@ func TestBlkioStatsNoQueuedFile(t *testing.T) {
 }
 
 func TestBlkioStatsNoServiceTimeFile(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
 	helper := NewCgroupTestUtil("blkio", t)
 	defer helper.cleanup()
 	helper.writeFileContents(map[string]string{
@@ -244,6 +247,9 @@ func TestBlkioStatsNoServiceTimeFile(t *testing.T) {
 }
 
 func TestBlkioStatsNoWaitTimeFile(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
 	helper := NewCgroupTestUtil("blkio", t)
 	defer helper.cleanup()
 	helper.writeFileContents(map[string]string{
@@ -265,6 +271,9 @@ func TestBlkioStatsNoWaitTimeFile(t *testing.T) {
 }
 
 func TestBlkioStatsNoMergedFile(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
 	helper := NewCgroupTestUtil("blkio", t)
 	defer helper.cleanup()
 	helper.writeFileContents(map[string]string{
@@ -286,6 +295,9 @@ func TestBlkioStatsNoMergedFile(t *testing.T) {
 }
 
 func TestBlkioStatsNoTimeFile(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
 	helper := NewCgroupTestUtil("blkio", t)
 	defer helper.cleanup()
 	helper.writeFileContents(map[string]string{

Godeps/_workspace/src/github.com/docker/libcontainer/network/stats.go

@@ -2,7 +2,6 @@ package network
 
 import (
 	"io/ioutil"
-	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -25,45 +24,51 @@ func GetStats(networkState *NetworkState) (*NetworkStats, error) {
 	if networkState.VethHost == "" {
 		return &NetworkStats{}, nil
 	}
-	data, err := readSysfsNetworkStats(networkState.VethHost)
+
-	if err != nil {
+	out := &NetworkStats{}
-		return nil, err
+
+	type netStatsPair struct {
+		// Where to write the output.
+		Out *uint64
+
+		// The network stats file to read.
+		File string
 	}
 
 	// Ingress for host veth is from the container. Hence tx_bytes stat on the host veth is actually number of bytes received by the container.
-	return &NetworkStats{
+	netStats := []netStatsPair{
-		RxBytes:   data["tx_bytes"],
+		{Out: &out.RxBytes, File: "tx_bytes"},
-		RxPackets: data["tx_packets"],
+		{Out: &out.RxPackets, File: "tx_packets"},
-		RxErrors:  data["tx_errors"],
+		{Out: &out.RxErrors, File: "tx_errors"},
-		RxDropped: data["tx_dropped"],
+		{Out: &out.RxDropped, File: "tx_dropped"},
-		TxBytes:   data["rx_bytes"],
+
-		TxPackets: data["rx_packets"],
+		{Out: &out.TxBytes, File: "rx_bytes"},
-		TxErrors:  data["rx_errors"],
+		{Out: &out.TxPackets, File: "rx_packets"},
-		TxDropped: data["rx_dropped"],
+		{Out: &out.TxErrors, File: "rx_errors"},
-	}, nil
+		{Out: &out.TxDropped, File: "rx_dropped"},
+	}
+	for _, netStat := range netStats {
+		data, err := readSysfsNetworkStats(networkState.VethHost, netStat.File)
+		if err != nil {
+			return nil, err
+		}
+		*(netStat.Out) = data
+	}
+
+	return out, nil
 }
 
-// Reads all the statistics available under /sys/class/net/<EthInterface>/statistics as a map with file name as key and data as integers.
+// Reads the specified statistics available under /sys/class/net/<EthInterface>/statistics
-func readSysfsNetworkStats(ethInterface string) (map[string]uint64, error) {
+func readSysfsNetworkStats(ethInterface, statsFile string) (uint64, error) {
-	out := make(map[string]uint64)
+	fullPath := filepath.Join("/sys/class/net", ethInterface, "statistics", statsFile)
+	data, err := ioutil.ReadFile(fullPath)
+	if err != nil {
+		return 0, err
+	}
+	value, err := strconv.ParseUint(strings.TrimSpace(string(data)), 10, 64)
+	if err != nil {
+		return 0, err
+	}
 
-	fullPath := filepath.Join("/sys/class/net", ethInterface, "statistics/")
+	return value, err
-	err := filepath.Walk(fullPath, func(path string, _ os.FileInfo, _ error) error {
-		// skip fullPath.
-		if path == fullPath {
-			return nil
-		}
-		base := filepath.Base(path)
-		data, err := ioutil.ReadFile(path)
-		if err != nil {
-			return err
-		}
-		value, err := strconv.ParseUint(strings.TrimSpace(string(data)), 10, 64)
-		if err != nil {
-			return err
-		}
-		out[base] = value
-		return nil
-	})
-	return out, err
 }