Introduce backend GUIDs (ggml/743)

* Introduce backend GUIDs

Initial proposed implementation of backend GUIDs
(Discussed in https://github.com/ggerganov/ggml/pull/741)

Hardcoded CPU backend GUID (for now)
Change ggml_backend_is_cpu logic to use GUID

* Remove redundant functions

Remove redundant functions `ggml_backend_i::get_name` and `ggml_backend_guid` which are not desired for future expansion

* Add spaces to match style

Co-authored-by: slaren <slarengh@gmail.com>

* Fix brace style to match

Co-authored-by: slaren <slarengh@gmail.com>

* Add void to () in function signature

Co-authored-by: slaren <slarengh@gmail.com>

* Add back ggml_backend_guid and make CPU_GUID a local static in ggml_backend_cpu_guid

* add guids to all backends

ggml-ci

---------

Co-authored-by: slaren <slarengh@gmail.com>

ggml-backend-impl.h

@@ -104,6 +104,8 @@ extern "C" {
     };
 
     struct ggml_backend {
+        ggml_guid_t guid;
+
         struct ggml_backend_i iface;
 
         ggml_backend_context_t context;

ggml-backend.c

@@ -12,7 +12,6 @@
 
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 
-
 // backend buffer type
 
 const char * ggml_backend_buft_name(ggml_backend_buffer_type_t buft) {
@@ -159,6 +158,13 @@ bool ggml_backend_buffer_copy_tensor(const struct ggml_tensor * src, struct ggml
 
 // backend
 
+ggml_guid_t ggml_backend_guid(ggml_backend_t backend) {
+    if (backend == NULL) {
+        return NULL;
+    }
+    return backend->guid;
+}
+
 const char * ggml_backend_name(ggml_backend_t backend) {
     if (backend == NULL) {
         return "NULL";
@@ -781,6 +787,11 @@ static struct ggml_backend_i cpu_backend_i = {
     /* .supports_op             = */ ggml_backend_cpu_supports_op,
 };
 
+static ggml_guid_t ggml_backend_cpu_guid(void) {
+    static ggml_guid guid = { 0xaa, 0x67, 0xc7, 0x43, 0x96, 0xe6, 0xa3, 0x8a, 0xe3, 0xaf, 0xea, 0x92, 0x36, 0xbc, 0xfc, 0x89 };
+    return &guid;
+}
+
 ggml_backend_t ggml_backend_cpu_init(void) {
     struct ggml_backend_cpu_context * ctx = malloc(sizeof(struct ggml_backend_cpu_context));
     if (ctx == NULL) {
@@ -800,6 +811,7 @@ ggml_backend_t ggml_backend_cpu_init(void) {
     }
 
     *cpu_backend = (struct ggml_backend) {
+        /* .guid      = */ ggml_backend_cpu_guid(),
         /* .interface = */ cpu_backend_i,
         /* .context   = */ ctx
     };
@@ -807,7 +819,7 @@ ggml_backend_t ggml_backend_cpu_init(void) {
 }
 
 GGML_CALL bool ggml_backend_is_cpu(ggml_backend_t backend) {
-    return backend && backend->iface.get_name == ggml_backend_cpu_name;
+    return backend != NULL && ggml_guid_matches(backend->guid, ggml_backend_cpu_guid());
 }
 
 void ggml_backend_cpu_set_n_threads(ggml_backend_t backend_cpu, int n_threads) {

ggml-backend.h

@@ -49,7 +49,7 @@ extern "C" {
     // Backend
     //
 
-
+    GGML_API ggml_guid_t  ggml_backend_guid(ggml_backend_t backend);
     GGML_API const char * ggml_backend_name(ggml_backend_t backend);
     GGML_API void         ggml_backend_free(ggml_backend_t backend);
 

ggml-cuda.cu

@@ -12277,6 +12277,11 @@ static ggml_backend_i ggml_backend_cuda_interface = {
     /* .supports_op             = */ ggml_backend_cuda_supports_op,
 };
 
+static ggml_guid_t ggml_backend_cuda_guid() {
+    static ggml_guid guid = { 0x2c, 0xdd, 0xe8, 0x1c, 0x65, 0xb3, 0x65, 0x73, 0x6a, 0x12, 0x88, 0x61, 0x1c, 0xc9, 0xdc, 0x25 };
+    return &guid;
+}
+
 GGML_CALL ggml_backend_t ggml_backend_cuda_init(int device) {
     ggml_init_cublas(); // TODO: remove from ggml.c
 
@@ -12294,6 +12299,7 @@ GGML_CALL ggml_backend_t ggml_backend_cuda_init(int device) {
     };
 
     ggml_backend_t cuda_backend = new ggml_backend {
+        /* .guid      = */ ggml_backend_cuda_guid(),
         /* .interface = */ ggml_backend_cuda_interface,
         /* .context   = */ ctx
     };
@@ -12302,7 +12308,7 @@ GGML_CALL ggml_backend_t ggml_backend_cuda_init(int device) {
 }
 
 GGML_CALL bool ggml_backend_is_cuda(ggml_backend_t backend) {
-    return backend && backend->iface.get_name == ggml_backend_cuda_name;
+    return backend != NULL && ggml_guid_matches(backend->guid, ggml_backend_cuda_guid());
 }
 
 GGML_CALL int ggml_backend_cuda_get_device_count() {

ggml-kompute.cpp

@@ -1953,11 +1953,17 @@ static struct ggml_backend_i kompute_backend_i = {
     /* .supports_op             = */ ggml_backend_kompute_supports_op,
 };
 
+static ggml_guid_t ggml_backend_kompute_guid() {
+    static ggml_guid guid = { 0x7b, 0x57, 0xdc, 0xaf, 0xde, 0x12, 0x1d, 0x49, 0xfb, 0x35, 0xfa, 0x9b, 0x18, 0x31, 0x1d, 0xca };
+    return &guid;
+}
+
 ggml_backend_t ggml_backend_kompute_init(int device) {
     GGML_ASSERT(s_kompute_context == nullptr);
     s_kompute_context = new ggml_kompute_context(device);
 
     ggml_backend_t kompute_backend = new ggml_backend {
+        /* .guid      = */ ggml_backend_kompute_guid(),
         /* .interface = */ kompute_backend_i,
         /* .context   = */ s_kompute_context,
     };
@@ -1966,7 +1972,7 @@ ggml_backend_t ggml_backend_kompute_init(int device) {
 }
 
 bool ggml_backend_is_kompute(ggml_backend_t backend) {
-    return backend && backend->iface.get_name == ggml_backend_kompute_name;
+    return backend != NULL && ggml_guid_matches(backend->guid, ggml_backend_kompute_guid());
 }
 
 static ggml_backend_t ggml_backend_reg_kompute_init(const char * params, void * user_data) {

ggml-metal.m

@@ -2771,6 +2771,11 @@ void ggml_backend_metal_log_set_callback(ggml_log_callback log_callback, void *
     ggml_metal_log_user_data = user_data;
 }
 
+static ggml_guid_t ggml_backend_metal_guid(void) {
+    static ggml_guid guid = { 0x81, 0xa1, 0x8b, 0x1e, 0x71, 0xec, 0x79, 0xed, 0x2b, 0x85, 0xdc, 0x8a, 0x61, 0x98, 0x30, 0xe6 };
+    return &guid;
+}
+
 ggml_backend_t ggml_backend_metal_init(void) {
     struct ggml_metal_context * ctx = ggml_metal_init(GGML_DEFAULT_N_THREADS);
 
@@ -2781,6 +2786,7 @@ ggml_backend_t ggml_backend_metal_init(void) {
     ggml_backend_t metal_backend = malloc(sizeof(struct ggml_backend));
 
     *metal_backend = (struct ggml_backend) {
+        /* .guid      = */ ggml_backend_metal_guid(),
         /* .interface = */ ggml_backend_metal_i,
         /* .context   = */ ctx,
     };
@@ -2789,7 +2795,7 @@ ggml_backend_t ggml_backend_metal_init(void) {
 }
 
 bool ggml_backend_is_metal(ggml_backend_t backend) {
-    return backend && backend->iface.get_name == ggml_backend_metal_name;
+    return backend != NULL && ggml_guid_matches(backend->guid, ggml_backend_metal_guid());
 }
 
 void ggml_backend_metal_set_n_cb(ggml_backend_t backend, int n_cb) {

ggml-sycl.cpp

@@ -15162,6 +15162,11 @@ static ggml_backend_i ggml_backend_sycl_interface = {
     /* .supports_op             = */ ggml_backend_sycl_supports_op,
 };
 
+static ggml_guid_t ggml_backend_sycl_guid() {
+    static ggml_guid guid = { 0x58, 0x05, 0x13, 0x8f, 0xcd, 0x3a, 0x61, 0x9d, 0xe7, 0xcd, 0x98, 0xa9, 0x03, 0xfd, 0x7c, 0x53 };
+    return &guid;
+}
+
 ggml_backend_t ggml_backend_sycl_init(int device) {
     ggml_init_sycl(); // TODO: remove from ggml.c
 
@@ -15179,6 +15184,7 @@ ggml_backend_t ggml_backend_sycl_init(int device) {
     };
 
     ggml_backend_t sycl_backend = new ggml_backend {
+        /* .guid      = */ ggml_backend_sycl_guid(),
         /* .interface = */ ggml_backend_sycl_interface,
         /* .context   = */ ctx
     };
@@ -15187,7 +15193,7 @@ ggml_backend_t ggml_backend_sycl_init(int device) {
 }
 
 bool ggml_backend_is_sycl(ggml_backend_t backend) {
-    return backend->iface.get_name == ggml_backend_sycl_name;
+    return backend != NULL && ggml_guid_matches(backend->guid, ggml_backend_sycl_guid());
 }
 
 static ggml_backend_t ggml_backend_reg_sycl_init(const char * params, void * user_data) {

ggml-vulkan.cpp

@@ -5244,6 +5244,11 @@ static ggml_backend_i ggml_backend_vk_interface = {
     /* .supports_op             = */ ggml_backend_vk_supports_op,
 };
 
+static ggml_guid_t ggml_backend_vk_guid() {
+    static ggml_guid guid = { 0xb8, 0xf7, 0x4f, 0x86, 0x40, 0x3c, 0xe1, 0x02, 0x91, 0xc8, 0xdd, 0xe9, 0x02, 0x3f, 0xc0, 0x2b };
+    return &guid;
+}
+
 GGML_CALL ggml_backend_t ggml_backend_vk_init(size_t idx) {
     if (vk_instance.initialized[idx]) {
         return vk_instance.backends[idx];
@@ -5262,6 +5267,7 @@ GGML_CALL ggml_backend_t ggml_backend_vk_init(size_t idx) {
     vk_instance.initialized[idx] = true;
 
     ggml_backend_t vk_backend = new ggml_backend {
+        /* .guid      = */ ggml_backend_vk_guid(),
         /* .interface = */ ggml_backend_vk_interface,
         /* .context   = */ &vk_instance.contexts[ctx->idx],
     };
@@ -5272,7 +5278,7 @@ GGML_CALL ggml_backend_t ggml_backend_vk_init(size_t idx) {
 }
 
 GGML_CALL bool ggml_backend_is_vk(ggml_backend_t backend) {
-    return backend && backend->iface.get_name == ggml_backend_vk_name;
+    return backend != NULL && ggml_guid_matches(backend->guid, ggml_backend_vk_guid());
 }
 
 GGML_CALL int ggml_backend_vk_get_device_count() {

ggml.c

@@ -355,6 +355,10 @@ void ggml_fp32_to_fp16_row(const float * x, ggml_fp16_t * y, int n) {
     }
 }
 
+bool ggml_guid_matches(ggml_guid_t guid_a, ggml_guid_t guid_b) {
+    return memcmp(guid_a, guid_b, sizeof(ggml_guid)) == 0;
+}
+
 //
 // timing
 //

ggml.h

@@ -672,6 +672,16 @@ extern "C" {
         GGML_NUMA_STRATEGY_COUNT
     };
 
+    //
+    // GUID
+    //
+
+    // GUID types
+    typedef uint8_t ggml_guid[16];
+    typedef ggml_guid * ggml_guid_t;
+
+    GGML_API bool ggml_guid_matches(ggml_guid_t guid_a, ggml_guid_t guid_b);
+
     // misc
 
     GGML_API void    ggml_time_init(void); // call this once at the beginning of the program