cli: Add configuration option for io-threads.

Add option to configure if IO needs to be in a separate IO thread.
Add tests to verify option is correctly parsed. The default value
is set to false for now.
This should be considered to be enabled by default in the future.

Fixes #132

Signed-off-by: Archana Shinde <archana.m.shinde@intel.com>

Makefile

@@ -101,6 +101,7 @@ DEFNETWORKMODEL := macvtap
 
 DEFDISABLEBLOCK := false
 DEFBLOCKSTORAGEDRIVER := virtio-scsi
+DEFENABLEIOTHREADS := false
 DEFENABLEMEMPREALLOC := false
 DEFENABLEHUGEPAGES := false
 DEFENABLESWAP := false
@@ -172,6 +173,7 @@ USER_VARS += DEFBRIDGES
 USER_VARS += DEFNETWORKMODEL
 USER_VARS += DEFDISABLEBLOCK
 USER_VARS += DEFBLOCKSTORAGEDRIVER
+USER_VARS += DEFENABLEIOTHREADS
 USER_VARS += DEFENABLEMEMPREALLOC
 USER_VARS += DEFENABLEHUGEPAGES
 USER_VARS += DEFENABLESWAP
@@ -263,6 +265,7 @@ const defaultBridgesCount uint32 = $(DEFBRIDGES)
 const defaultInterNetworkingModel = "$(DEFNETWORKMODEL)"
 const defaultDisableBlockDeviceUse bool = $(DEFDISABLEBLOCK)
 const defaultBlockDeviceDriver = "$(DEFBLOCKSTORAGEDRIVER)"
+const defaultEnableIOThreads bool = $(DEFENABLEIOTHREADS)
 const defaultEnableMemPrealloc bool = $(DEFENABLEMEMPREALLOC)
 const defaultEnableHugePages bool = $(DEFENABLEHUGEPAGES)
 const defaultEnableSwap bool = $(DEFENABLESWAP)
@@ -346,6 +349,7 @@ $(GENERATED_FILES): %: %.in Makefile VERSION
 		-e "s|@DEFNETWORKMODEL@|$(DEFNETWORKMODEL)|g" \
 		-e "s|@DEFDISABLEBLOCK@|$(DEFDISABLEBLOCK)|g" \
 		-e "s|@DEFBLOCKSTORAGEDRIVER@|$(DEFBLOCKSTORAGEDRIVER)|g" \
+		-e "s|@DEFENABLEIOTHREADS@|$(DEFENABLEIOTHREADS)|g" \
 		-e "s|@DEFENABLEMEMPREALLOC@|$(DEFENABLEMEMPREALLOC)|g" \
 		-e "s|@DEFENABLEHUGEPAGES@|$(DEFENABLEHUGEPAGES)|g" \
 		-e "s|@DEFENABLEMSWAP@|$(DEFENABLESWAP)|g" \

cli/config.go

@@ -92,6 +92,7 @@ type hypervisor struct {
 	Swap                  bool   `toml:"enable_swap"`
 	Debug                 bool   `toml:"enable_debug"`
 	DisableNestingChecks  bool   `toml:"disable_nesting_checks"`
+	EnableIOThreads       bool   `toml:"enable_iothreads"`
 }
 
 type proxy struct {
@@ -321,6 +322,7 @@ func newQemuHypervisorConfig(h hypervisor) (vc.HypervisorConfig, error) {
 		Debug:                 h.Debug,
 		DisableNestingChecks:  h.DisableNestingChecks,
 		BlockDeviceDriver:     blockDriver,
+		EnableIOThreads:       h.EnableIOThreads,
 	}, nil
 }
 
@@ -423,6 +425,7 @@ func loadConfiguration(configPath string, ignoreLogging bool) (resolvedConfigPat
 		Debug:                 defaultEnableDebug,
 		DisableNestingChecks:  defaultDisableNestingChecks,
 		BlockDeviceDriver:     defaultBlockDeviceDriver,
+		EnableIOThreads:       defaultEnableIOThreads,
 	}
 
 	err = config.InterNetworkModel.SetModel(defaultInterNetworkingModel)

cli/config/configuration.toml.in

@@ -70,6 +70,12 @@ disable_block_device_use = @DEFDISABLEBLOCK@
 # virtio-blk.
 block_device_driver = "@DEFBLOCKSTORAGEDRIVER@"
 
+# Enable iothreads (data-plane) to be used. This causes IO to be
+# handled in a separate IO thread. This is currently only implemented
+# for SCSI.
+#
+enable_iothreads = @DEFENABLEIOTHREADS@
+
 # Enable pre allocation of VM RAM, default false
 # Enabling this will result in lower container density
 # as all of the memory will be allocated and locked

cli/config_test.go

@@ -41,7 +41,7 @@ type testRuntimeConfig struct {
 	LogPath           string
 }
 
-func makeRuntimeConfigFileData(hypervisor, hypervisorPath, kernelPath, imagePath, kernelParams, machineType, shimPath, proxyPath, logPath string, disableBlock bool, blockDeviceDriver string) string {
+func makeRuntimeConfigFileData(hypervisor, hypervisorPath, kernelPath, imagePath, kernelParams, machineType, shimPath, proxyPath, logPath string, disableBlock bool, blockDeviceDriver string, enableIOThreads bool) string {
 	return `
 	# Runtime configuration file
 
@@ -55,6 +55,7 @@ func makeRuntimeConfigFileData(hypervisor, hypervisorPath, kernelPath, imagePath
 	default_vcpus = ` + strconv.FormatUint(uint64(defaultVCPUCount), 10) + `
 	default_memory = ` + strconv.FormatUint(uint64(defaultMemSize), 10) + `
 	disable_block_device_use =  ` + strconv.FormatBool(disableBlock) + `
+	enable_iothreads =  ` + strconv.FormatBool(enableIOThreads) + `
 
 	[proxy.kata]
 	path = "` + proxyPath + `"
@@ -101,8 +102,9 @@ func createAllRuntimeConfigFiles(dir, hypervisor string) (config testRuntimeConf
 	machineType := "machineType"
 	disableBlockDevice := true
 	blockDeviceDriver := "virtio-scsi"
+	enableIOThreads := true
 
-	runtimeConfigFileData := makeRuntimeConfigFileData(hypervisor, hypervisorPath, kernelPath, imagePath, kernelParams, machineType, shimPath, proxyPath, logPath, disableBlockDevice, blockDeviceDriver)
+	runtimeConfigFileData := makeRuntimeConfigFileData(hypervisor, hypervisorPath, kernelPath, imagePath, kernelParams, machineType, shimPath, proxyPath, logPath, disableBlockDevice, blockDeviceDriver, enableIOThreads)
 
 	configPath := path.Join(dir, "runtime.toml")
 	err = createConfig(configPath, runtimeConfigFileData)
@@ -140,6 +142,7 @@ func createAllRuntimeConfigFiles(dir, hypervisor string) (config testRuntimeConf
 		BlockDeviceDriver:     defaultBlockDeviceDriver,
 		DefaultBridges:        defaultBridgesCount,
 		Mlock:                 !defaultEnableSwap,
+		EnableIOThreads:       enableIOThreads,
 	}
 
 	agentConfig := vc.KataAgentConfig{}
@@ -569,6 +572,7 @@ func TestNewQemuHypervisorConfig(t *testing.T) {
 	imagePath := path.Join(dir, "image")
 	machineType := "machineType"
 	disableBlock := true
+	enableIOThreads := true
 
 	hypervisor := hypervisor{
 		Path:                  hypervisorPath,
@@ -576,6 +580,7 @@ func TestNewQemuHypervisorConfig(t *testing.T) {
 		Image:                 imagePath,
 		MachineType:           machineType,
 		DisableBlockDeviceUse: disableBlock,
+		EnableIOThreads:       enableIOThreads,
 	}
 
 	files := []string{hypervisorPath, kernelPath, imagePath}
@@ -617,6 +622,10 @@ func TestNewQemuHypervisorConfig(t *testing.T) {
 		t.Errorf("Expected value for disable block usage %v, got %v", disableBlock, config.DisableBlockDeviceUse)
 	}
 
+	if config.EnableIOThreads != enableIOThreads {
+		t.Errorf("Expected value for enable IOThreads  %v, got %v", enableIOThreads, config.EnableIOThreads)
+	}
+
 }
 
 func TestNewShimConfig(t *testing.T) {

cli/kata-env_test.go

@@ -69,6 +69,7 @@ func makeRuntimeConfig(prefixDir string) (configFile string, config oci.RuntimeC
 	proxyPath := filepath.Join(prefixDir, "proxy")
 	disableBlock := true
 	blockStorageDriver := "virtio-scsi"
+	enableIOThreads := true
 
 	// override
 	defaultProxyPath = proxyPath
@@ -112,7 +113,9 @@ func makeRuntimeConfig(prefixDir string) (configFile string, config oci.RuntimeC
 		testProxyURL,
 		logPath,
 		disableBlock,
-		blockStorageDriver)
+		blockStorageDriver,
+		enableIOThreads,
+	)
 
 	configFile = path.Join(prefixDir, "runtime.toml")
 	err = createConfig(configFile, runtimeConfig)