Add capability to set a default device for all threads

docs/docs/icicle/programmers_guide/cpp.md

@@ -32,6 +32,21 @@ eIcicleError result = icicle_set_device(device);
 eIcicleError result = icicle_get_active_device(device);
 ```
 
+### Setting and Getting the Default Device
+
+You can set the default device for all threads:
+
+```cpp
+icicle::Device device = {"CUDA", 0}; // or other
+eIcicleError result = icicle_set_default_device(device);
+```
+
+:::caution
+
+Setting a default device should be done **once** from the main thread of the application. If another device or backend is needed for a specific thread [icicle_set_device](#setting-and-getting-active-device) should be used instead.
+
+:::
+
 ### Querying Device Information
 
 Retrieve the number of available devices and check if a pointer is allocated on the host or on the active device:

docs/docs/icicle/programmers_guide/general.md

@@ -85,6 +85,7 @@ ICICLE provides a device abstraction layer that allows you to interact with diff
 
 - **Loading Backends**: Backends are loaded dynamically based on the environment configuration or a specified path.
 - **Setting Active Device**: The active device for a thread can be set, allowing for targeted computation on a specific device.
+- **Setting Default Device**: The default device for any thread without an active device can be set, removing the need to specify an alternative device on each thread. This is especially useful when running on a backend that is not the built-in CPU backend which is the default device to start.
 
 ## Streams
 

docs/docs/icicle/programmers_guide/go.md

@@ -27,12 +27,27 @@ result := runtime.LoadBackend("/path/to/backend/installdir", true)
 You can set the active device for the current thread and retrieve it when needed:
 
 ```go
-device = runtime.CreateDevice("CUDA", 0) // or other
+device := runtime.CreateDevice("CUDA", 0) // or other
 result := runtime.SetDevice(device)
 // or query current (thread) device 
 activeDevice := runtime.GetActiveDevice()
 ```
 
+### Setting and Getting the Default Device
+
+You can set the default device for all threads:
+
+```go
+device := runtime.CreateDevice("CUDA", 0) // or other
+defaultDevice := runtime.SetDefaultDevice(device);
+```
+
+:::caution
+
+Setting a default device should be done **once** from the main thread of the application. If another device or backend is needed for a specific thread [runtime.SetDevice](#setting-and-getting-active-device) should be used instead.
+
+:::
+
 ### Querying Device Information
 
 Retrieve the number of available devices and check if a pointer is allocated on the host or on the active device:

docs/docs/icicle/programmers_guide/rust.md

@@ -55,6 +55,21 @@ icicle_runtime::set_device(&device).unwrap();
 let active_device = icicle_runtime::get_active_device().unwrap();
 ```
 
+### Setting and Getting the Default Device
+
+You can set the default device for all threads:
+
+```caution
+let device = Device::new("CUDA", 0); // or other
+let default_device = icicle_runtime::set_default_device(device);
+```
+
+:::note
+
+Setting a default device should be done **once** from the main thread of the application. If another device or backend is needed for a specific thread [icicle_runtime::set_device](#setting-and-getting-active-device) should be used instead.
+
+:::
+
 ### Querying Device Information
 
 Retrieve the number of available devices and check if a pointer is allocated on the host or on the active device:

icicle/include/icicle/device_api.h

@@ -188,6 +188,7 @@ namespace icicle {
 
   public:
     static eIcicleError set_thread_local_device(const Device& device);
+    static eIcicleError set_default_device(const Device& device);
     static const Device& get_thread_local_device();
     static const DeviceAPI* get_thread_local_deviceAPI();
     static DeviceTracker& get_global_memory_tracker() { return sMemTracker; }

icicle/include/icicle/runtime.h

@@ -36,6 +36,14 @@ extern "C" eIcicleError icicle_load_backend_from_env_or_default();
  */
 extern "C" eIcicleError icicle_set_device(const icicle::Device& device);
 
+/**
+ * @brief Set default device for all threads
+ *
+
+ * @return eIcicleError::SUCCESS if successful, otherwise throws INVALID_DEVICE
+ */
+extern "C" eIcicleError icicle_set_default_device(const icicle::Device& device);
+
 /**
  * @brief Get active device for thread
  *

icicle/src/device_api.cpp

@@ -58,6 +58,17 @@ namespace icicle {
 
     const Device& get_default_device() { return m_default_device; }
 
+    eIcicleError set_default_device(const Device& dev)
+    {
+      if (!is_device_registered(dev.type)) {
+        ICICLE_LOG_ERROR << "Device type " + std::string(dev.type) + " is not valid as it has not been registered";
+        return eIcicleError::INVALID_DEVICE;
+      }
+
+      m_default_device = dev;
+      return eIcicleError::SUCCESS;
+    }
+
     std::vector<std::string> get_registered_devices_list()
     {
       std::vector<std::string> registered_devices;
@@ -116,6 +127,11 @@ namespace icicle {
     return default_deviceAPI.get();
   }
 
+  eIcicleError DeviceAPI::set_default_device(const Device& dev)
+  {
+    return DeviceAPIRegistry::Global().set_default_device(dev);
+  }
+
   /********************************************************************************** */
 
   DeviceAPI* get_deviceAPI(const Device& device) { return DeviceAPIRegistry::Global().get_deviceAPI(device).get(); }

icicle/src/runtime.cpp

@@ -14,6 +14,11 @@ using namespace icicle;
 
 extern "C" eIcicleError icicle_set_device(const Device& device) { return DeviceAPI::set_thread_local_device(device); }
 
+extern "C" eIcicleError icicle_set_default_device(const Device& device)
+{
+  return DeviceAPI::set_default_device(device);
+}
+
 extern "C" eIcicleError icicle_get_active_device(icicle::Device& device)
 {
   const Device& active_device = DeviceAPI::get_thread_local_device();

icicle/tests/test_device_api.cpp

@@ -1,5 +1,6 @@
 
 #include <gtest/gtest.h>
+#include <thread>
 #include <iostream>
 
 #include "icicle/runtime.h"
@@ -19,6 +20,36 @@ TEST_F(DeviceApiTest, UnregisteredDeviceError)
   EXPECT_ANY_THROW(get_deviceAPI(dev));
 }
 
+TEST_F(DeviceApiTest, SetDefaultDevice)
+{
+  icicle::Device active_dev = {UNKOWN_DEVICE, -1};
+
+  icicle::Device cpu_dev = {s_ref_device, 0};
+  EXPECT_NO_THROW(icicle_set_device(cpu_dev));
+  EXPECT_NO_THROW(icicle_get_active_device(active_dev));
+
+  ASSERT_EQ(cpu_dev, active_dev);
+
+  active_dev = {UNKOWN_DEVICE, -1};
+
+  icicle::Device gpu_dev = {s_main_device, 0};
+  EXPECT_NO_THROW(icicle_set_default_device(gpu_dev));
+
+  // setting a new default device doesn't override already set local thread devices
+  EXPECT_NO_THROW(icicle_get_active_device(active_dev));
+  ASSERT_EQ(cpu_dev, active_dev);
+
+  active_dev = {UNKOWN_DEVICE, -1};
+  auto thread_func = [&active_dev, &gpu_dev]() {
+    EXPECT_NO_THROW(icicle_get_active_device(active_dev));
+    ASSERT_EQ(gpu_dev, active_dev);
+  };
+
+  std::thread worker_thread(thread_func);
+
+  worker_thread.join();
+}
+
 TEST_F(DeviceApiTest, MemoryCopySync)
 {
   int input[2] = {1, 2};

wrappers/golang/runtime/device.go

@@ -50,6 +50,12 @@ func SetDevice(device *Device) EIcicleError {
 	return EIcicleError(cErr)
 }
 
+func SetDefaultDevice(device *Device) EIcicleError {
+	cDevice := (*C.Device)(unsafe.Pointer(device))
+	cErr := C.icicle_set_default_device(cDevice)
+	return EIcicleError(cErr)
+}
+
 func GetActiveDevice() (*Device, EIcicleError) {
 	device := CreateDevice("invalid", -1)
 	cDevice := (*C.Device)(unsafe.Pointer(&device))

wrappers/golang/runtime/include/runtime.h

@@ -13,6 +13,7 @@ typedef struct DeviceProperties DeviceProperties;
 int icicle_load_backend(const char* path, bool is_recursive);
 int icicle_load_backend_from_env_or_default();
 int icicle_set_device(const Device* device);
+int icicle_set_default_device(const Device* device);
 int icicle_get_active_device(Device* device);
 int icicle_is_host_memory(const void* ptr);
 int icicle_is_active_device_memory(const void* ptr);

wrappers/golang/runtime/tests/device_test.go

@@ -1,70 +1,122 @@
 package tests
 
 import (
+	"fmt"
 	"os/exec"
+	"runtime"
+	"strconv"
+	"strings"
+	"syscall"
 	"testing"
 
-	"github.com/ingonyama-zk/icicle/v3/wrappers/golang/runtime"
+	icicle_runtime "github.com/ingonyama-zk/icicle/v3/wrappers/golang/runtime"
 
 	"github.com/stretchr/testify/assert"
 )
 
 func TestGetDeviceType(t *testing.T) {
 	expectedDeviceName := "test"
-	config := runtime.CreateDevice(expectedDeviceName, 0)
+	config := icicle_runtime.CreateDevice(expectedDeviceName, 0)
 	assert.Equal(t, expectedDeviceName, config.GetDeviceType())
 
 	expectedDeviceNameLong := "testtesttesttesttesttesttesttesttesttesttesttesttesttesttesttest"
-	configLargeName := runtime.CreateDevice(expectedDeviceNameLong, 1)
+	configLargeName := icicle_runtime.CreateDevice(expectedDeviceNameLong, 1)
 	assert.NotEqual(t, expectedDeviceNameLong, configLargeName.GetDeviceType())
 }
 
 func TestIsDeviceAvailable(t *testing.T) {
-	runtime.LoadBackendFromEnvOrDefault()
-	dev := runtime.CreateDevice("CUDA", 0)
-	_ = runtime.SetDevice(&dev)
-	res, err := runtime.GetDeviceCount()
-
-	expectedNumDevices, error := exec.Command("nvidia-smi", "-L", "|", "wc", "-l").Output()
-	if error != nil {
-		t.Skip("Failed to get number of devices")
+	dev := icicle_runtime.CreateDevice("CUDA", 0)
+	_ = icicle_runtime.SetDevice(&dev)
+	res, err := icicle_runtime.GetDeviceCount()
+
+	smiCommand := exec.Command("nvidia-smi", "-L")
+	smiCommandStdout, _ := smiCommand.StdoutPipe()
+	wcCommand := exec.Command("wc", "-l")
+	wcCommand.Stdin = smiCommandStdout
+
+	smiCommand.Start()
+
+	expectedNumDevicesRaw, wcErr := wcCommand.Output()
+	smiCommand.Wait()
+
+	expectedNumDevicesAsString := strings.TrimRight(string(expectedNumDevicesRaw), " \n\r\t")
+	expectedNumDevices, _ := strconv.Atoi(expectedNumDevicesAsString)
+	if wcErr != nil {
+		t.Skip("Failed to get number of devices:", wcErr)
 	}
 
-	assert.Equal(t, runtime.Success, err)
+	assert.Equal(t, icicle_runtime.Success, err)
 	assert.Equal(t, expectedNumDevices, res)
 
-	err = runtime.LoadBackendFromEnvOrDefault()
-	assert.Equal(t, runtime.Success, err)
-	devCuda := runtime.CreateDevice("CUDA", 0)
-	assert.True(t, runtime.IsDeviceAvailable(&devCuda))
-	devCpu := runtime.CreateDevice("CPU", 0)
-	assert.True(t, runtime.IsDeviceAvailable(&devCpu))
-	devInvalid := runtime.CreateDevice("invalid", 0)
-	assert.False(t, runtime.IsDeviceAvailable(&devInvalid))
+	assert.Equal(t, icicle_runtime.Success, err)
+	devCuda := icicle_runtime.CreateDevice("CUDA", 0)
+	assert.True(t, icicle_runtime.IsDeviceAvailable(&devCuda))
+	devCpu := icicle_runtime.CreateDevice("CPU", 0)
+	assert.True(t, icicle_runtime.IsDeviceAvailable(&devCpu))
+	devInvalid := icicle_runtime.CreateDevice("invalid", 0)
+	assert.False(t, icicle_runtime.IsDeviceAvailable(&devInvalid))
+}
+
+func TestSetDefaultDevice(t *testing.T) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+	tidOuter := syscall.Gettid()
+
+	gpuDevice := icicle_runtime.CreateDevice("CUDA", 0)
+	icicle_runtime.SetDefaultDevice(&gpuDevice)
+
+	activeDevice, err := icicle_runtime.GetActiveDevice()
+	assert.Equal(t, icicle_runtime.Success, err)
+	assert.Equal(t, gpuDevice, *activeDevice)
+
+	done := make(chan struct{}, 1)
+	go func() {
+		runtime.LockOSThread()
+		defer runtime.UnlockOSThread()
+
+		// Ensure we are operating on an OS thread other than the original one
+		tidInner := syscall.Gettid()
+		for tidInner == tidOuter {
+			fmt.Println("Locked thread is the same as original, getting new locked thread")
+			runtime.UnlockOSThread()
+			runtime.LockOSThread()
+			tidInner = syscall.Gettid()
+		}
+
+		activeDevice, err := icicle_runtime.GetActiveDevice()
+		assert.Equal(t, icicle_runtime.Success, err)
+		assert.Equal(t, gpuDevice, *activeDevice)
+
+		close(done)
+	}()
+
+	<-done
+
+	cpuDevice := icicle_runtime.CreateDevice("CPU", 0)
+	icicle_runtime.SetDefaultDevice(&cpuDevice)
 }
 
 func TestRegisteredDevices(t *testing.T) {
-	err := runtime.LoadBackendFromEnvOrDefault()
-	assert.Equal(t, runtime.Success, err)
-	devices, _ := runtime.GetRegisteredDevices()
+	devices, _ := icicle_runtime.GetRegisteredDevices()
 	assert.Equal(t, []string{"CUDA", "CPU"}, devices)
 }
 
 func TestDeviceProperties(t *testing.T) {
-	_, err := runtime.GetDeviceProperties()
-	assert.Equal(t, runtime.Success, err)
+	_, err := icicle_runtime.GetDeviceProperties()
+	assert.Equal(t, icicle_runtime.Success, err)
 }
 
 func TestActiveDevice(t *testing.T) {
-	runtime.SetDevice(&DEVICE)
-	activeDevice, err := runtime.GetActiveDevice()
-	assert.Equal(t, runtime.Success, err)
-	assert.Equal(t, DEVICE, *activeDevice)
-	memory1, err := runtime.GetAvailableMemory()
-	if err == runtime.ApiNotImplemented {
-		t.Skipf("GetAvailableMemory() function is not implemented on %s device", DEVICE.GetDeviceType())
+	devCpu := icicle_runtime.CreateDevice("CUDA", 0)
+	icicle_runtime.SetDevice(&devCpu)
+	activeDevice, err := icicle_runtime.GetActiveDevice()
+	assert.Equal(t, icicle_runtime.Success, err)
+	assert.Equal(t, devCpu, *activeDevice)
+	memory1, err := icicle_runtime.GetAvailableMemory()
+	if err == icicle_runtime.ApiNotImplemented {
+		t.Skipf("GetAvailableMemory() function is not implemented on %s device", devCpu.GetDeviceType())
 	}
-	assert.Equal(t, runtime.Success, err)
+	assert.Equal(t, icicle_runtime.Success, err)
 	assert.Greater(t, memory1.Total, uint(0))
 	assert.Greater(t, memory1.Free, uint(0))
 }

wrappers/golang/runtime/tests/main_test.go

@@ -6,19 +6,7 @@ import (
 	"github.com/ingonyama-zk/icicle/v3/wrappers/golang/runtime"
 )
 
-var DEVICE runtime.Device
-
 func TestMain(m *testing.M) {
 	runtime.LoadBackendFromEnvOrDefault()
-	devices, e := runtime.GetRegisteredDevices()
-	if e != runtime.Success {
-		panic("Failed to load registered devices")
-	}
-	for _, deviceType := range devices {
-		DEVICE = runtime.CreateDevice(deviceType, 0)
-		runtime.SetDevice(&DEVICE)
-
-		// execute tests
-		m.Run()
-	}
+	m.Run()
 }