Merge pull request #446 from rjnagal/diskinfo

Add scheduler type to disk info.

info/machine.go

@@ -93,6 +93,9 @@ type DiskInfo struct {
 
 	// Size in bytes
 	Size uint64 `json:"size"`
+
+	// I/O Scheduler - one of "none", "noop", "cfq", "deadline"
+	Scheduler string `json:"scheduler"`
 }
 
 type NetInfo struct {

utils/sysfs/fakesysfs/fake.go

@@ -64,6 +64,10 @@ func (self *FakeSysFs) GetBlockDeviceSize(name string) (string, error) {
 	return "1234567", nil
 }
 
+func (self *FakeSysFs) GetBlockDeviceScheduler(name string) (string, error) {
+	return "noop deadline [cfq]", nil
+}
+
 func (self *FakeSysFs) GetBlockDeviceNumbers(name string) (string, error) {
 	return "8:0\n", nil
 }

utils/sysfs/sysfs.go

@@ -45,6 +45,8 @@ type SysFs interface {
 	GetBlockDevices() ([]os.FileInfo, error)
 	// Get Size of a given block device.
 	GetBlockDeviceSize(string) (string, error)
+	// Get scheduler type for the block device.
+	GetBlockDeviceScheduler(string) (string, error)
 	// Get device major:minor number string.
 	GetBlockDeviceNumbers(string) (string, error)
 
@@ -78,6 +80,14 @@ func (self *realSysFs) GetBlockDeviceNumbers(name string) (string, error) {
 	return string(dev), nil
 }
 
+func (self *realSysFs) GetBlockDeviceScheduler(name string) (string, error) {
+	sched, err := ioutil.ReadFile(path.Join(blockDir, name, "/queue/scheduler"))
+	if err != nil {
+		return "", err
+	}
+	return string(sched), nil
+}
+
 func (self *realSysFs) GetBlockDeviceSize(name string) (string, error) {
 	size, err := ioutil.ReadFile(path.Join(blockDir, name, "/size"))
 	if err != nil {

utils/sysinfo/sysinfo.go

@@ -16,6 +16,7 @@ package sysinfo
 
 import (
 	"fmt"
+	"regexp"
 	"strconv"
 	"strings"
 
@@ -23,6 +24,8 @@ import (
 	"github.com/google/cadvisor/utils/sysfs"
 )
 
+var schedulerRegExp = regexp.MustCompile(".*\\[(.*)\\].*")
+
 // Get information about block devices present on the system.
 // Uses the passed in system interface to retrieve the low level OS information.
 func GetBlockDeviceInfo(sysfs sysfs.SysFs) (map[string]info.DiskInfo, error) {
@@ -62,6 +65,18 @@ func GetBlockDeviceInfo(sysfs sysfs.SysFs) (map[string]info.DiskInfo, error) {
 		// size is in 512 bytes blocks.
 		disk_info.Size = size * 512
 
+		sched, err := sysfs.GetBlockDeviceScheduler(name)
+		if err != nil {
+			sched = "none"
+		} else {
+			matches := schedulerRegExp.FindSubmatch([]byte(sched))
+			if len(matches) < 2 {
+				sched = "none"
+			} else {
+				sched = string(matches[1])
+			}
+		}
+		disk_info.Scheduler = sched
 		device := fmt.Sprintf("%d:%d", disk_info.Major, disk_info.Minor)
 		diskMap[device] = disk_info
 	}

utils/sysinfo/sysinfo_test.go

@@ -43,6 +43,9 @@ func TestGetBlockDeviceInfo(t *testing.T) {
 	if disk.Size != size {
 		t.Errorf("expected to get disk size of %d. Got %d", size, disk.Size)
 	}
+	if disk.Scheduler != "cfq" {
+		t.Errorf("expected to get scheduler type of cfq. Got %q", disk.Scheduler)
+	}
 }
 
 func TestGetNetworkDevices(t *testing.T) {