implement get_alignment and get_max_size

ggml-rpc.cpp

@@ -42,6 +42,8 @@ static ggml_guid_t ggml_backend_rpc_guid() {
 struct ggml_backend_rpc_buffer_type_context {
     std::shared_ptr<sockfd> sock;
     std::string name;
+    size_t alignment;
+    size_t max_size;
 };
 
 struct ggml_backend_rpc_context {
@@ -346,16 +348,40 @@ GGML_CALL static ggml_backend_buffer_t ggml_backend_rpc_buffer_type_alloc_buffer
     return buffer;
 }
 
+static size_t get_alignment(const std::shared_ptr<sockfd> & sock) {
+    // input serialization format: | 0 bytes |
+    std::vector<uint8_t> input;
+    std::vector<uint8_t> output;
+    bool status = send_rpc_cmd(sock, GET_ALIGNMENT, input, output);
+    GGML_ASSERT(status);
+    GGML_ASSERT(output.size() == sizeof(uint64_t));
+    // output serialization format: | alignment (8 bytes) |
+    uint64_t alignment;
+    memcpy(&alignment, output.data(), sizeof(alignment));
+    return alignment;
+}
+
 GGML_CALL static size_t ggml_backend_rpc_buffer_type_get_alignment(ggml_backend_buffer_type_t buft) {
-    UNUSED(buft);
-    // TODO: this is hardcoded for now but it should come from the remote backend
-    return 128;
+    ggml_backend_rpc_buffer_type_context * buft_ctx = (ggml_backend_rpc_buffer_type_context *)buft->context;
+    return buft_ctx->alignment;
+}
+
+static size_t get_max_size(const std::shared_ptr<sockfd> & sock) {
+    // input serialization format: | 0 bytes |
+    std::vector<uint8_t> input;
+    std::vector<uint8_t> output;
+    bool status = send_rpc_cmd(sock, GET_MAX_SIZE, input, output);
+    GGML_ASSERT(status);
+    GGML_ASSERT(output.size() == sizeof(uint64_t));
+    // output serialization format: | max_size (8 bytes) |
+    uint64_t max_size;
+    memcpy(&max_size, output.data(), sizeof(max_size));
+    return max_size;
 }
 
 GGML_CALL static size_t ggml_backend_rpc_get_max_size(ggml_backend_buffer_type_t buft) {
-    UNUSED(buft);
-    // TODO: this is hardcoded for now but it should come from the remote backend
-    return SIZE_MAX;
+    ggml_backend_rpc_buffer_type_context * buft_ctx = (ggml_backend_rpc_buffer_type_context *)buft->context;
+    return buft_ctx->max_size;
 }
 
 GGML_CALL static size_t ggml_backend_rpc_buffer_type_get_alloc_size(ggml_backend_buffer_type_t buft, const ggml_tensor * tensor) {
@@ -505,10 +531,13 @@ GGML_CALL ggml_backend_t ggml_backend_rpc_init(const std::string & endpoint) {
     if (sock == nullptr) {
         return nullptr;
     }
-
+    size_t alignment = get_alignment(sock);
+    size_t max_size = get_max_size(sock);
     ggml_backend_rpc_buffer_type_context * buft_ctx = new ggml_backend_rpc_buffer_type_context {
         /* .sock   = */ sock,
-        /* .name   = */ "RPC" + std::to_string(sock->fd)
+        /* .name   = */ "RPC" + std::to_string(sock->fd),
+        /* .alignment = */ alignment,
+        /* .max_size = */ max_size
     };
 
     ggml_backend_buffer_type_t buft = new ggml_backend_buffer_type {
@@ -560,6 +589,24 @@ static void rpc_alloc_buffer(ggml_backend_t backend, const std::vector<uint8_t>
     memcpy(output.data() + sizeof(uint64_t), &remote_size, sizeof(remote_size));
 }
 
+static void rpc_get_alignment(ggml_backend_t backend, std::vector<uint8_t> & output) {
+    ggml_backend_buffer_type_t buft = ggml_backend_get_default_buffer_type(backend);
+    size_t alignment = ggml_backend_buft_get_alignment(buft);
+    GGML_PRINT_DEBUG("[%s] alignment: %lu\n", __func__, alignment);
+    // output serialization format: | alignment (8 bytes) |
+    output.resize(sizeof(uint64_t), 0);
+    memcpy(output.data(), &alignment, sizeof(alignment));
+}
+
+static void rpc_get_max_size(ggml_backend_t backend, std::vector<uint8_t> & output) {
+    ggml_backend_buffer_type_t buft = ggml_backend_get_default_buffer_type(backend);
+    size_t max_size = ggml_backend_buft_get_max_size(buft);
+    GGML_PRINT_DEBUG("[%s] max_size: %lu\n", __func__, max_size);
+    // output serialization format: | max_size (8 bytes) |
+    output.resize(sizeof(uint64_t), 0);
+    memcpy(output.data(), &max_size, sizeof(max_size));
+}
+
 static void rpc_buffer_get_base(const std::vector<uint8_t> & input, std::vector<uint8_t> & output) {
     // input serialization format: | remote_ptr (8 bytes) |
     uint64_t remote_ptr;
@@ -733,6 +780,14 @@ void rpc_serve_client(ggml_backend_t backend, int sockfd) {
                 rpc_alloc_buffer(backend, input, output);
                 break;
             }
+            case GET_ALIGNMENT: {
+                rpc_get_alignment(backend, output);
+                break;
+            }
+            case GET_MAX_SIZE: {
+                rpc_get_max_size(backend, output);
+                break;
+            }
             case BUFFER_GET_BASE: {
                 rpc_buffer_get_base(input, output);
                 break;

ggml-rpc.h

@@ -28,6 +28,8 @@ struct rpc_tensor {
 // RPC commands
 enum rpc_cmd {
     ALLOC_BUFFER = 0,
+    GET_ALIGNMENT,
+    GET_MAX_SIZE,
     BUFFER_GET_BASE,
     FREE_BUFFER,
     BUFFER_CLEAR,