Add flush request and time spend flushing diskstats for kernel 5.5+ (#289)

* add flush request and time spend flushing diskstats for kernel 5.5+

Signed-off-by: binjip978 <[email protected]>

* add diskstats if at least 14 params are present

Signed-off-by: binjip978 <[email protected]>

Author: Sergei Sementchouk

blockdevice/stats.go

@@ -69,21 +69,26 @@ type IOStats struct {
 	DiscardSectors uint64
 	// DiscardTicks is the total number of milliseconds spent by all discards.
 	DiscardTicks uint64
+	// FlushRequestsCompleted is the total number of flush request completed successfully.
+	FlushRequestsCompleted uint64
+	// TimeSpentFlushing is the total number of milliseconds spent flushing.
+	TimeSpentFlushing uint64
 }
 
 // Diskstats combines the device Info and IOStats
 type Diskstats struct {
 	Info
 	IOStats
-	// IoStatsCount contains the number of io stats read.  For kernel versions
-	// 4.18+, there should be 18 fields read.  For earlier kernel versions this
+	// IoStatsCount contains the number of io stats read. For kernel versions 5.5+,
+	// there should be 20 fields read. For kernel versions 4.18+,
+	// there should be 18 fields read. For earlier kernel versions this
 	// will be 14 because the discard values are not available.
 	IoStatsCount int
 }
 
 const (
 	procDiskstatsPath   = "diskstats"
-	procDiskstatsFormat = "%d %d %s %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d"
+	procDiskstatsFormat = "%d %d %s %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d"
 	sysBlockPath        = "block"
 	sysBlockStatFormat  = "%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d"
 )
@@ -153,13 +158,15 @@ func (fs FS) ProcDiskstats() ([]Diskstats, error) {
 			&d.DiscardMerges,
 			&d.DiscardSectors,
 			&d.DiscardTicks,
+			&d.FlushRequestsCompleted,
+			&d.TimeSpentFlushing,
 		)
 		// The io.EOF error can be safely ignored because it just means we read fewer than
-		// the full 18 fields.
+		// the full 20 fields.
 		if err != nil && err != io.EOF {
 			return diskstats, err
 		}
-		if d.IoStatsCount == 14 || d.IoStatsCount == 18 {
+		if d.IoStatsCount >= 14 {
 			diskstats = append(diskstats, *d)
 		}
 	}

blockdevice/stats_test.go

@@ -32,7 +32,7 @@ func TestDiskstats(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	expectedNumOfDevices := 49
+	expectedNumOfDevices := 52
 	if len(diskstats) != expectedNumOfDevices {
 		t.Errorf(failMsgFormat, "Incorrect number of devices", expectedNumOfDevices, len(diskstats))
 	}
@@ -51,6 +51,15 @@ func TestDiskstats(t *testing.T) {
 	if diskstats[48].IoStatsCount != 18 {
 		t.Errorf(failMsgFormat, "Incorrect number of stats read", 18, diskstats[48].IoStatsCount)
 	}
+	if diskstats[49].IoStatsCount != 20 {
+		t.Errorf(failMsgFormat, "Incorrect number of stats read", 20, diskstats[50].IoStatsCount)
+	}
+	if diskstats[49].FlushRequestsCompleted != 127 {
+		t.Errorf(failMsgFormat, "Incorrect number of flash requests completed", 127, diskstats[50].FlushRequestsCompleted)
+	}
+	if diskstats[49].TimeSpentFlushing != 182 {
+		t.Errorf(failMsgFormat, "Incorrect time spend flushing", 182, diskstats[50].TimeSpentFlushing)
+	}
 }
 
 func TestBlockDevice(t *testing.T) {

fixtures.ttar

@@ -1841,7 +1841,7 @@ max keysize  : 32
 Mode: 444
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Path: fixtures/proc/diskstats
-Lines: 49
+Lines: 52
    1       0 ram0 0 0 0 0 0 0 0 0 0 0 0
    1       1 ram1 0 0 0 0 0 0 0 0 0 0 0
    1       2 ram2 0 0 0 0 0 0 0 0 0 0 0
@@ -1891,6 +1891,9 @@ Lines: 49
    8       0 sdb 326552 841 9657779 84 41822 2895 1972905 5007 0 60730 67070 68851 0 1925173784 11130
    8       1 sdb1 231 3 34466 4 24 23 106 0 0 64 64 0 0 0 0
    8       2 sdb2 326310 838 9622281 67 40726 2872 1972799 4924 0 58250 64567 68851 0 1925173784 11130
+   8       0 sdc 14202 71 579164 21861 2995 1589 180500 40875 0 11628 55200 0 0 0 0 127 182
+   8       1 sdc1 1027 0 13795 5021 2 0 4096 3 0 690 4579 0 0 0 0 0 0
+   8       2 sdc2 13126 71 561749 16802 2830 1589 176404 40620 0 10931 50449 0 0 0 0 0 0
 Mode: 664
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: fixtures/proc/fs