[SYCL] fix multi-gpu issue on sycl (#8554)

---------

Signed-off-by: Chen Xi <xi2chen@intel.com>
Co-authored-by: Meng, Hengyu <hengyu.meng@intel.com>

docs/backend/SYCL.md

@@ -293,31 +293,26 @@ Similar to the native `sycl-ls`, available SYCL devices can be queried as follow
 ```sh
 ./build/bin/llama-ls-sycl-device
 ```
-A example of such log in a system with 1 *intel CPU* and 1 *intel GPU* can look like the following:
+This command will only display the selected backend that is supported by SYCL. The default backend is level_zero. For example, in a system with 2 *intel GPU* it would look like the following:
 ```
-found 6 SYCL devices:
+found 2 SYCL devices:
+
 |  |                  |                                             |Compute   |Max compute|Max work|Max sub|               |
 |ID|       Device Type|                                         Name|capability|units      |group   |group  |Global mem size|
 |--|------------------|---------------------------------------------|----------|-----------|--------|-------|---------------|
 | 0|[level_zero:gpu:0]|               Intel(R) Arc(TM) A770 Graphics|       1.3|        512|    1024|     32|    16225243136|
 | 1|[level_zero:gpu:1]|                    Intel(R) UHD Graphics 770|       1.3|         32|     512|     32|    53651849216|
-| 2|    [opencl:gpu:0]|               Intel(R) Arc(TM) A770 Graphics|       3.0|        512|    1024|     32|    16225243136|
-| 3|    [opencl:gpu:1]|                    Intel(R) UHD Graphics 770|       3.0|         32|     512|     32|    53651849216|
-| 4|    [opencl:cpu:0]|         13th Gen Intel(R) Core(TM) i7-13700K|       3.0|         24|    8192|     64|    67064815616|
-| 5|    [opencl:acc:0]|               Intel(R) FPGA Emulation Device|       1.2|         24|67108864|     64|    67064815616|
 ```
 
-| Attribute              | Note                                                        |
-|------------------------|-------------------------------------------------------------|
-| compute capability 1.3 | Level-zero driver/runtime, recommended                      |
-| compute capability 3.0 | OpenCL driver/runtime, slower than level-zero in most cases |
 
 4. Launch inference
 
 There are two device selection modes:
 
 - Single device: Use one device target specified by the user.
-- Multiple devices: Automatically select the devices with the same largest Max compute-units.
+- Multiple devices: Automatically choose the devices with the same backend.
+
+In two device selection modes, the default SYCL backend is level_zero, you can choose other backend supported by SYCL by setting environment variable ONEAPI_DEVICE_SELECTOR.
 
 | Device selection | Parameter                              |
 |------------------|----------------------------------------|
@@ -474,33 +469,26 @@ Similar to the native `sycl-ls`, available SYCL devices can be queried as follow
 build\bin\ls-sycl-device.exe
 ```
 
-The output of this command in a system with 1 *intel CPU* and 1 *intel GPU* would look like the following:
+This command will only display the selected backend that is supported by SYCL. The default backend is level_zero. For example, in a system with 2 *intel GPU* it would look like the following:
 ```
-found 6 SYCL devices:
+found 2 SYCL devices:
 |  |                  |                                             |Compute   |Max compute|Max work|Max sub|               |
 |ID|       Device Type|                                         Name|capability|units      |group   |group  |Global mem size|
 |--|------------------|---------------------------------------------|----------|-----------|--------|-------|---------------|
 | 0|[level_zero:gpu:0]|               Intel(R) Arc(TM) A770 Graphics|       1.3|        512|    1024|     32|    16225243136|
 | 1|[level_zero:gpu:1]|                    Intel(R) UHD Graphics 770|       1.3|         32|     512|     32|    53651849216|
-| 2|    [opencl:gpu:0]|               Intel(R) Arc(TM) A770 Graphics|       3.0|        512|    1024|     32|    16225243136|
-| 3|    [opencl:gpu:1]|                    Intel(R) UHD Graphics 770|       3.0|         32|     512|     32|    53651849216|
-| 4|    [opencl:cpu:0]|         13th Gen Intel(R) Core(TM) i7-13700K|       3.0|         24|    8192|     64|    67064815616|
-| 5|    [opencl:acc:0]|               Intel(R) FPGA Emulation Device|       1.2|         24|67108864|     64|    67064815616|
 
 ```
 
-| Attribute              | Note                                                      |
-|------------------------|-----------------------------------------------------------|
-| compute capability 1.3 | Level-zero running time, recommended                      |
-| compute capability 3.0 | OpenCL running time, slower than level-zero in most cases |
-
 
 4. Launch inference
 
 There are two device selection modes:
 
-- Single device: Use one device assigned by user.
-- Multiple devices: Automatically choose the devices with the same biggest Max compute units.
+- Single device: Use one device assigned by user. Default device id is 0.
+- Multiple devices: Automatically choose the devices with the same backend.
+
+In two device selection modes, the default SYCL backend is level_zero, you can choose other backend supported by SYCL by setting environment variable ONEAPI_DEVICE_SELECTOR.
 
 | Device selection | Parameter                              |
 |------------------|----------------------------------------|

ggml/src/ggml-sycl/common.hpp

@@ -267,7 +267,7 @@ struct ggml_backend_sycl_context {
 
     queue_ptr stream(int device, int stream) {
         if (qptrs[device][stream] == nullptr) {
-            qptrs[device][stream] = &(dpct::get_current_device().default_queue());
+            qptrs[device][stream] = &(dpct::get_device(device).default_queue());
         }
         return qptrs[device][stream];
     }

ggml/src/ggml-sycl/dpct/helper.hpp

@@ -588,7 +588,7 @@ namespace dpct
         out = prop;
     }
 
-   /// dpct device extension
+    /// dpct device extension
     class device_ext : public sycl::device {
       typedef std::mutex mutex_type;
 
@@ -697,7 +697,7 @@ namespace dpct
         std::unique_lock<mutex_type> lock(m_mutex);
         lock.unlock();
         for (auto &q : _queues) {
-          q.wait_and_throw();
+            q.wait_and_throw();
         }
         // Guard the destruct of current_queues to make sure the ref count is
         // safe.
@@ -734,7 +734,12 @@ namespace dpct
 
       void destroy_queue(sycl::queue queue) {
         std::lock_guard<mutex_type> lock(m_mutex);
-        _queues.clear();
+        _queues.erase(std::remove_if(_queues.begin(), _queues.end(),
+                                    [=](const sycl::queue &q) -> bool
+                                    {
+                                        return q == queue;
+                                    }),
+                    _queues.end());
       }
       void set_saved_queue(sycl::queue q) {
         std::lock_guard<mutex_type> lock(m_mutex);
@@ -764,13 +769,13 @@ namespace dpct
         if (enable_exception_handler) {
           eh = exception_handler;
         }
-        auto q = sycl::queue(*this, eh,
-                             sycl::property_list(
+        _queues.push_back(sycl::queue(
+            *this, eh,
+            sycl::property_list(
 #ifdef DPCT_PROFILING_ENABLED
-                                 sycl::property::queue::enable_profiling(),
+                sycl::property::queue::enable_profiling(),
 #endif
-                                 properties...));
-        _queues.push_back(q);
+                properties...)));
 
         return _queues.back();
       }
@@ -783,8 +788,8 @@ namespace dpct
         if (enable_exception_handler) {
           eh = exception_handler;
         }
-        _queues.push_back(
-            sycl::queue(device, eh,
+        _queues.push_back(sycl::queue(
+            device, eh,
                         sycl::property_list(
 #ifdef DPCT_PROFILING_ENABLED
                             sycl::property::queue::enable_profiling(),
@@ -855,15 +860,75 @@ namespace dpct
         unsigned int get_device_id(const sycl::device &dev)
         {
             unsigned int id = 0;
-            for (auto dev_item : _devs)
+            for (auto &dev_item : _devs)
             {
                 if (*dev_item == dev)
                 {
-                    break;
+                    return id;
                 }
                 id++;
             }
-            return id;
+            return -1;
+        }
+
+        inline std::string get_preferred_gpu_platform_name() {
+            std::string result;
+
+            std::string filter = "level-zero";
+            char* env = getenv("ONEAPI_DEVICE_SELECTOR");
+            if (env) {
+                if (std::strstr(env, "level_zero")) {
+                    filter = "level-zero";
+                }
+                else if (std::strstr(env, "opencl")) {
+                    filter = "opencl";
+                }
+                else if (std::strstr(env, "cuda")) {
+                    filter = "cuda";
+                }
+                else if (std::strstr(env, "hip")) {
+                    filter = "hip";
+                }
+                else {
+                    throw std::runtime_error("invalid device filter: " + std::string(env));
+                }
+            }
+
+            auto plaform_list = sycl::platform::get_platforms();
+
+            for (const auto& platform : plaform_list) {
+                auto devices = platform.get_devices();
+                auto gpu_dev = std::find_if(devices.begin(), devices.end(), [](const sycl::device& d) {
+                    return d.is_gpu();
+                });
+
+                if (gpu_dev == devices.end()) {
+                    // cout << "platform [" << platform_name
+                    //      << "] does not contain GPU devices, skipping\n";
+                    continue;
+                }
+
+                auto platform_name = platform.get_info<sycl::info::platform::name>();
+                std::string platform_name_low_case;
+                platform_name_low_case.resize(platform_name.size());
+
+                std::transform(
+                    platform_name.begin(), platform_name.end(), platform_name_low_case.begin(), ::tolower);
+
+                if (platform_name_low_case.find(filter) == std::string::npos) {
+                    // cout << "platform [" << platform_name
+                    //      << "] does not match with requested "
+                    //      << filter << ", skipping\n";
+                    continue;
+                }
+
+                result = platform_name;
+            }
+
+            if (result.empty())
+                throw std::runtime_error("can not find preferred GPU platform");
+
+            return result;
         }
 
         template <class DeviceSelector>
@@ -930,10 +995,15 @@ namespace dpct
             // Keep track of the number of devices per backend
             std::map<sycl::backend, size_t> DeviceNums;
             std::map<std::string, std::vector<sycl::device>> backend_devices;
+            auto preferred_platform_name = get_preferred_gpu_platform_name();
 
             while (!Platforms.empty()) {
                 auto Platform = Platforms.back();
                 Platforms.pop_back();
+                auto platform_name = Platform.get_info<sycl::info::platform::name>();
+                if (platform_name.compare(preferred_platform_name) != 0) {
+                    continue;
+                }
                 auto devices = Platform.get_devices();
                 std::string backend_type = get_device_backend_and_type(devices[0]);
                 for (const auto &device : devices) {
@@ -1989,6 +2059,11 @@ namespace dpct
         return dev_mgr::instance().current_device();
     }
 
+    static inline device_ext &get_device(unsigned int id)
+    {
+        return dev_mgr::instance().get_device(id);
+    }
+
     static inline sycl::queue &get_in_order_queue()
     {
         return dev_mgr::instance().current_device().in_order_queue();

src/llama.cpp

@@ -16643,9 +16643,7 @@ struct llama_context * llama_new_context_with_model(
             for (int i = 0; i < ggml_backend_sycl_get_device_count(); ++i) {
                 ggml_backend_t backend = ggml_backend_sycl_init(i);
                 if (backend == nullptr) {
-                    int id_list[GGML_SYCL_MAX_DEVICES];
-                    ggml_sycl_get_gpu_list(id_list, GGML_SYCL_MAX_DEVICES);
-                    LLAMA_LOG_ERROR("%s: failed to initialize SYCL%d (index %d) backend\n", __func__, id_list[i], i);
+                    LLAMA_LOG_ERROR("%s: failed to initialize SYCL%d for No.%d backend\n", __func__, i, i);
                     llama_free(ctx);
                     return nullptr;
                 }