// +build linux package fs import ( "strconv" "testing" "github.com/opencontainers/runc/libcontainer/cgroups" "github.com/opencontainers/runc/libcontainer/configs" ) const ( sectorsRecursiveContents = `8:0 1024` serviceBytesRecursiveContents = `8:0 Read 100 8:0 Write 200 8:0 Sync 300 8:0 Async 500 8:0 Total 500 Total 500` servicedRecursiveContents = `8:0 Read 10 8:0 Write 40 8:0 Sync 20 8:0 Async 30 8:0 Total 50 Total 50` queuedRecursiveContents = `8:0 Read 1 8:0 Write 4 8:0 Sync 2 8:0 Async 3 8:0 Total 5 Total 5` serviceTimeRecursiveContents = `8:0 Read 173959 8:0 Write 0 8:0 Sync 0 8:0 Async 173959 8:0 Total 17395 Total 17395` waitTimeRecursiveContents = `8:0 Read 15571 8:0 Write 0 8:0 Sync 0 8:0 Async 15571 8:0 Total 15571` mergedRecursiveContents = `8:0 Read 5 8:0 Write 10 8:0 Sync 0 8:0 Async 0 8:0 Total 15 Total 15` timeRecursiveContents = `8:0 8` throttleServiceBytes = `8:0 Read 11030528 8:0 Write 23 8:0 Sync 42 8:0 Async 11030528 8:0 Total 11030528 252:0 Read 11030528 252:0 Write 23 252:0 Sync 42 252:0 Async 11030528 252:0 Total 11030528 Total 22061056` throttleServiced = `8:0 Read 164 8:0 Write 23 8:0 Sync 42 8:0 Async 164 8:0 Total 164 252:0 Read 164 252:0 Write 23 252:0 Sync 42 252:0 Async 164 252:0 Total 164 Total 328` ) func appendBlkioStatEntry(blkioStatEntries *[]cgroups.BlkioStatEntry, major, minor, value uint64, op string) { *blkioStatEntries = append(*blkioStatEntries, cgroups.BlkioStatEntry{Major: major, Minor: minor, Value: value, Op: op}) } func TestBlkioSetWeight(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() const ( weightBefore = 100 weightAfter = 200 ) helper.writeFileContents(map[string]string{ "blkio.weight": strconv.Itoa(weightBefore), }) helper.CgroupData.c.BlkioWeight = weightAfter blkio := &BlkioGroup{} if err := blkio.Set(helper.CgroupPath, helper.CgroupData.c); err != nil { t.Fatal(err) } value, err := getCgroupParamUint(helper.CgroupPath, "blkio.weight") if err != nil { t.Fatalf("Failed to parse blkio.weight - %s", err) } if value != weightAfter { t.Fatal("Got the wrong value, set blkio.weight failed.") } } func TestBlkioSetWeightDevice(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() const ( weightDeviceBefore = "8:0 400" ) wd := configs.NewWeightDevice(8, 0, 500, 0) weightDeviceAfter := wd.WeightString() helper.writeFileContents(map[string]string{ "blkio.weight_device": weightDeviceBefore, }) helper.CgroupData.c.BlkioWeightDevice = []*configs.WeightDevice{wd} blkio := &BlkioGroup{} if err := blkio.Set(helper.CgroupPath, helper.CgroupData.c); err != nil { t.Fatal(err) } value, err := getCgroupParamString(helper.CgroupPath, "blkio.weight_device") if err != nil { t.Fatalf("Failed to parse blkio.weight_device - %s", err) } if value != weightDeviceAfter { t.Fatal("Got the wrong value, set blkio.weight_device failed.") } } // regression #274 func TestBlkioSetMultipleWeightDevice(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() const ( weightDeviceBefore = "8:0 400" ) wd1 := configs.NewWeightDevice(8, 0, 500, 0) wd2 := configs.NewWeightDevice(8, 16, 500, 0) // we cannot actually set and check both because normal ioutil.WriteFile // when writing to cgroup file will overwrite the whole file content instead // of updating it as the kernel is doing. Just check the second device // is present will suffice for the test to ensure multiple writes are done. weightDeviceAfter := wd2.WeightString() helper.writeFileContents(map[string]string{ "blkio.weight_device": weightDeviceBefore, }) helper.CgroupData.c.BlkioWeightDevice = []*configs.WeightDevice{wd1, wd2} blkio := &BlkioGroup{} if err := blkio.Set(helper.CgroupPath, helper.CgroupData.c); err != nil { t.Fatal(err) } value, err := getCgroupParamString(helper.CgroupPath, "blkio.weight_device") if err != nil { t.Fatalf("Failed to parse blkio.weight_device - %s", err) } if value != weightDeviceAfter { t.Fatal("Got the wrong value, set blkio.weight_device failed.") } } func TestBlkioStats(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() helper.writeFileContents(map[string]string{ "blkio.io_service_bytes_recursive": serviceBytesRecursiveContents, "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatal(err) } // Verify expected stats. expectedStats := cgroups.BlkioStats{} appendBlkioStatEntry(&expectedStats.SectorsRecursive, 8, 0, 1024, "") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 100, "Read") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 200, "Write") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 300, "Sync") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 500, "Async") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 500, "Total") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 10, "Read") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 40, "Write") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 20, "Sync") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 30, "Async") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 50, "Total") appendBlkioStatEntry(&expectedStats.IoQueuedRecursive, 8, 0, 1, "Read") appendBlkioStatEntry(&expectedStats.IoQueuedRecursive, 8, 0, 4, "Write") appendBlkioStatEntry(&expectedStats.IoQueuedRecursive, 8, 0, 2, "Sync") appendBlkioStatEntry(&expectedStats.IoQueuedRecursive, 8, 0, 3, "Async") appendBlkioStatEntry(&expectedStats.IoQueuedRecursive, 8, 0, 5, "Total") appendBlkioStatEntry(&expectedStats.IoServiceTimeRecursive, 8, 0, 173959, "Read") appendBlkioStatEntry(&expectedStats.IoServiceTimeRecursive, 8, 0, 0, "Write") appendBlkioStatEntry(&expectedStats.IoServiceTimeRecursive, 8, 0, 0, "Sync") appendBlkioStatEntry(&expectedStats.IoServiceTimeRecursive, 8, 0, 173959, "Async") appendBlkioStatEntry(&expectedStats.IoServiceTimeRecursive, 8, 0, 17395, "Total") appendBlkioStatEntry(&expectedStats.IoWaitTimeRecursive, 8, 0, 15571, "Read") appendBlkioStatEntry(&expectedStats.IoWaitTimeRecursive, 8, 0, 0, "Write") appendBlkioStatEntry(&expectedStats.IoWaitTimeRecursive, 8, 0, 0, "Sync") appendBlkioStatEntry(&expectedStats.IoWaitTimeRecursive, 8, 0, 15571, "Async") appendBlkioStatEntry(&expectedStats.IoWaitTimeRecursive, 8, 0, 15571, "Total") appendBlkioStatEntry(&expectedStats.IoMergedRecursive, 8, 0, 5, "Read") appendBlkioStatEntry(&expectedStats.IoMergedRecursive, 8, 0, 10, "Write") appendBlkioStatEntry(&expectedStats.IoMergedRecursive, 8, 0, 0, "Sync") appendBlkioStatEntry(&expectedStats.IoMergedRecursive, 8, 0, 0, "Async") appendBlkioStatEntry(&expectedStats.IoMergedRecursive, 8, 0, 15, "Total") appendBlkioStatEntry(&expectedStats.IoTimeRecursive, 8, 0, 8, "") expectBlkioStatsEquals(t, expectedStats, actualStats.BlkioStats) } func TestBlkioStatsNoSectorsFile(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() helper.writeFileContents(map[string]string{ "blkio.io_service_bytes_recursive": serviceBytesRecursiveContents, "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatalf("Failed unexpectedly: %s", err) } } func TestBlkioStatsNoServiceBytesFile(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() helper.writeFileContents(map[string]string{ "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatalf("Failed unexpectedly: %s", err) } } func TestBlkioStatsNoServicedFile(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() helper.writeFileContents(map[string]string{ "blkio.io_service_bytes_recursive": serviceBytesRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatalf("Failed unexpectedly: %s", err) } } func TestBlkioStatsNoQueuedFile(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() helper.writeFileContents(map[string]string{ "blkio.io_service_bytes_recursive": serviceBytesRecursiveContents, "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatalf("Failed unexpectedly: %s", err) } } 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{ "blkio.io_service_bytes_recursive": serviceBytesRecursiveContents, "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatalf("Failed unexpectedly: %s", err) } } 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{ "blkio.io_service_bytes_recursive": serviceBytesRecursiveContents, "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatalf("Failed unexpectedly: %s", err) } } 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{ "blkio.io_service_bytes_recursive": serviceBytesRecursiveContents, "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.time_recursive": timeRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatalf("Failed unexpectedly: %s", err) } } 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{ "blkio.io_service_bytes_recursive": serviceBytesRecursiveContents, "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatalf("Failed unexpectedly: %s", err) } } func TestBlkioStatsUnexpectedNumberOfFields(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() helper.writeFileContents(map[string]string{ "blkio.io_service_bytes_recursive": "8:0 Read 100 100", "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err == nil { t.Fatal("Expected to fail, but did not") } } func TestBlkioStatsUnexpectedFieldType(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() helper.writeFileContents(map[string]string{ "blkio.io_service_bytes_recursive": "8:0 Read Write", "blkio.io_serviced_recursive": servicedRecursiveContents, "blkio.io_queued_recursive": queuedRecursiveContents, "blkio.sectors_recursive": sectorsRecursiveContents, "blkio.io_service_time_recursive": serviceTimeRecursiveContents, "blkio.io_wait_time_recursive": waitTimeRecursiveContents, "blkio.io_merged_recursive": mergedRecursiveContents, "blkio.time_recursive": timeRecursiveContents, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err == nil { t.Fatal("Expected to fail, but did not") } } func TestNonCFQBlkioStats(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() helper.writeFileContents(map[string]string{ "blkio.io_service_bytes_recursive": "", "blkio.io_serviced_recursive": "", "blkio.io_queued_recursive": "", "blkio.sectors_recursive": "", "blkio.io_service_time_recursive": "", "blkio.io_wait_time_recursive": "", "blkio.io_merged_recursive": "", "blkio.time_recursive": "", "blkio.throttle.io_service_bytes": throttleServiceBytes, "blkio.throttle.io_serviced": throttleServiced, }) blkio := &BlkioGroup{} actualStats := *cgroups.NewStats() err := blkio.GetStats(helper.CgroupPath, &actualStats) if err != nil { t.Fatal(err) } // Verify expected stats. expectedStats := cgroups.BlkioStats{} appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 11030528, "Read") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 23, "Write") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 42, "Sync") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 11030528, "Async") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 8, 0, 11030528, "Total") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 252, 0, 11030528, "Read") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 252, 0, 23, "Write") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 252, 0, 42, "Sync") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 252, 0, 11030528, "Async") appendBlkioStatEntry(&expectedStats.IoServiceBytesRecursive, 252, 0, 11030528, "Total") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 164, "Read") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 23, "Write") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 42, "Sync") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 164, "Async") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 8, 0, 164, "Total") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 252, 0, 164, "Read") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 252, 0, 23, "Write") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 252, 0, 42, "Sync") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 252, 0, 164, "Async") appendBlkioStatEntry(&expectedStats.IoServicedRecursive, 252, 0, 164, "Total") expectBlkioStatsEquals(t, expectedStats, actualStats.BlkioStats) } func TestBlkioSetThrottleReadBpsDevice(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() const ( throttleBefore = `8:0 1024` ) td := configs.NewThrottleDevice(8, 0, 2048) throttleAfter := td.String() helper.writeFileContents(map[string]string{ "blkio.throttle.read_bps_device": throttleBefore, }) helper.CgroupData.c.BlkioThrottleReadBpsDevice = []*configs.ThrottleDevice{td} blkio := &BlkioGroup{} if err := blkio.Set(helper.CgroupPath, helper.CgroupData.c); err != nil { t.Fatal(err) } value, err := getCgroupParamString(helper.CgroupPath, "blkio.throttle.read_bps_device") if err != nil { t.Fatalf("Failed to parse blkio.throttle.read_bps_device - %s", err) } if value != throttleAfter { t.Fatal("Got the wrong value, set blkio.throttle.read_bps_device failed.") } } func TestBlkioSetThrottleWriteBpsDevice(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() const ( throttleBefore = `8:0 1024` ) td := configs.NewThrottleDevice(8, 0, 2048) throttleAfter := td.String() helper.writeFileContents(map[string]string{ "blkio.throttle.write_bps_device": throttleBefore, }) helper.CgroupData.c.BlkioThrottleWriteBpsDevice = []*configs.ThrottleDevice{td} blkio := &BlkioGroup{} if err := blkio.Set(helper.CgroupPath, helper.CgroupData.c); err != nil { t.Fatal(err) } value, err := getCgroupParamString(helper.CgroupPath, "blkio.throttle.write_bps_device") if err != nil { t.Fatalf("Failed to parse blkio.throttle.write_bps_device - %s", err) } if value != throttleAfter { t.Fatal("Got the wrong value, set blkio.throttle.write_bps_device failed.") } } func TestBlkioSetThrottleReadIOpsDevice(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() const ( throttleBefore = `8:0 1024` ) td := configs.NewThrottleDevice(8, 0, 2048) throttleAfter := td.String() helper.writeFileContents(map[string]string{ "blkio.throttle.read_iops_device": throttleBefore, }) helper.CgroupData.c.BlkioThrottleReadIOPSDevice = []*configs.ThrottleDevice{td} blkio := &BlkioGroup{} if err := blkio.Set(helper.CgroupPath, helper.CgroupData.c); err != nil { t.Fatal(err) } value, err := getCgroupParamString(helper.CgroupPath, "blkio.throttle.read_iops_device") if err != nil { t.Fatalf("Failed to parse blkio.throttle.read_iops_device - %s", err) } if value != throttleAfter { t.Fatal("Got the wrong value, set blkio.throttle.read_iops_device failed.") } } func TestBlkioSetThrottleWriteIOpsDevice(t *testing.T) { helper := NewCgroupTestUtil("blkio", t) defer helper.cleanup() const ( throttleBefore = `8:0 1024` ) td := configs.NewThrottleDevice(8, 0, 2048) throttleAfter := td.String() helper.writeFileContents(map[string]string{ "blkio.throttle.write_iops_device": throttleBefore, }) helper.CgroupData.c.BlkioThrottleWriteIOPSDevice = []*configs.ThrottleDevice{td} blkio := &BlkioGroup{} if err := blkio.Set(helper.CgroupPath, helper.CgroupData.c); err != nil { t.Fatal(err) } value, err := getCgroupParamString(helper.CgroupPath, "blkio.throttle.write_iops_device") if err != nil { t.Fatalf("Failed to parse blkio.throttle.write_iops_device - %s", err) } if value != throttleAfter { t.Fatal("Got the wrong value, set blkio.throttle.write_iops_device failed.") } }