rpc : report actual free memory (#16616)

* rpc : report actual free memory

Start reporting the free memory on every device instead of using
fixed values. Now llama-cli users can get a nice memory breakdown
when using RPC devices.

* drop --mem in rpc-server

ggml/include/ggml-rpc.h

@@ -21,8 +21,7 @@ GGML_BACKEND_API ggml_backend_buffer_type_t ggml_backend_rpc_buffer_type(const c
 GGML_BACKEND_API void ggml_backend_rpc_get_device_memory(const char * endpoint, uint32_t device, size_t * free, size_t * total);
 
 GGML_BACKEND_API void ggml_backend_rpc_start_server(const char * endpoint, const char * cache_dir,
-                                                    size_t n_threads, size_t n_devices,
+                                                    size_t n_threads, size_t n_devices, ggml_backend_dev_t * devices);
-                                                    ggml_backend_dev_t * devices, size_t * free_mem, size_t * total_mem);
 
 GGML_BACKEND_API ggml_backend_reg_t ggml_backend_rpc_reg(void);
 GGML_BACKEND_API ggml_backend_reg_t ggml_backend_rpc_add_server(const char * endpoint);

ggml/src/ggml-rpc/ggml-rpc.cpp

@@ -939,6 +939,7 @@ public:
     bool graph_compute(const std::vector<uint8_t> & input, rpc_msg_graph_compute_rsp & response);
     bool init_tensor(const rpc_msg_init_tensor_req & request);
     bool get_alloc_size(const rpc_msg_get_alloc_size_req & request, rpc_msg_get_alloc_size_rsp & response);
+    bool get_device_memory(const rpc_msg_get_device_memory_req & request, rpc_msg_get_device_memory_rsp & response);
 
 private:
     bool get_cached_file(uint64_t hash, std::vector<uint8_t> & data);
@@ -1458,6 +1459,20 @@ bool rpc_server::graph_compute(const std::vector<uint8_t> & input, rpc_msg_graph
     return true;
 }
 
+bool rpc_server::get_device_memory(const rpc_msg_get_device_memory_req & request, rpc_msg_get_device_memory_rsp & response) {
+    uint32_t dev_id = request.device;
+    if (dev_id >= backends.size()) {
+        return false;
+    }
+    size_t free, total;
+    ggml_backend_dev_t dev = ggml_backend_get_device(backends[dev_id]);
+    ggml_backend_dev_memory(dev, &free, &total);
+    response.free_mem = free;
+    response.total_mem = total;
+    LOG_DBG("[%s] device: %u, free_mem: %" PRIu64 ", total_mem: %" PRIu64 "\n", __func__, dev_id, response.free_mem, response.total_mem);
+    return true;
+}
+
 rpc_server::~rpc_server() {
     for (auto buffer : buffers) {
         ggml_backend_buffer_free(buffer);
@@ -1465,7 +1480,7 @@ rpc_server::~rpc_server() {
 }
 
 static void rpc_serve_client(const std::vector<ggml_backend_t> & backends, const char * cache_dir,
-                             sockfd_t sockfd, const std::vector<size_t> & free_mem, const std::vector<size_t> & total_mem) {
+                             sockfd_t sockfd) {
     rpc_server server(backends, cache_dir);
     uint8_t cmd;
     if (!recv_data(sockfd, &cmd, 1)) {
@@ -1689,15 +1704,10 @@ static void rpc_serve_client(const std::vector<ggml_backend_t> & backends, const
                 if (!recv_msg(sockfd, &request, sizeof(request))) {
                     return;
                 }
-                auto dev_id = request.device;
+                rpc_msg_get_device_memory_rsp response;
-                if (dev_id >= backends.size()) {
+                if (!server.get_device_memory(request, response)) {
                     return;
                 }
-                rpc_msg_get_device_memory_rsp response;
-                response.free_mem = free_mem[dev_id];
-                response.total_mem = total_mem[dev_id];
-                LOG_DBG("[get_device_mem] device: %u, free_mem: %" PRIu64 ", total_mem: %" PRIu64 "\n", dev_id,
-                    response.free_mem, response.total_mem);
                 if (!send_msg(sockfd, &response, sizeof(response))) {
                     return;
                 }
@@ -1712,15 +1722,12 @@ static void rpc_serve_client(const std::vector<ggml_backend_t> & backends, const
 }
 
 void ggml_backend_rpc_start_server(const char * endpoint, const char * cache_dir,
-                                   size_t n_threads, size_t n_devices,
+                                   size_t n_threads, size_t n_devices, ggml_backend_dev_t * devices) {
-                                   ggml_backend_dev_t * devices, size_t * free_mem, size_t * total_mem) {
+    if (n_devices == 0 || devices == nullptr) {
-    if (n_devices == 0 || devices == nullptr || free_mem == nullptr || total_mem == nullptr) {
         fprintf(stderr, "Invalid arguments to ggml_backend_rpc_start_server\n");
         return;
     }
     std::vector<ggml_backend_t> backends;
-    std::vector<size_t> free_mem_vec(free_mem, free_mem + n_devices);
-    std::vector<size_t> total_mem_vec(total_mem, total_mem + n_devices);
     printf("Starting RPC server v%d.%d.%d\n",
         RPC_PROTO_MAJOR_VERSION,
         RPC_PROTO_MINOR_VERSION,
@@ -1730,8 +1737,10 @@ void ggml_backend_rpc_start_server(const char * endpoint, const char * cache_dir
     printf("Devices:\n");
     for (size_t i = 0; i < n_devices; i++) {
         auto dev = devices[i];
+        size_t free, total;
+        ggml_backend_dev_memory(dev, &free, &total);
         printf("  %s: %s (%zu MiB, %zu MiB free)\n", ggml_backend_dev_name(dev), ggml_backend_dev_description(dev),
-               total_mem[i] / 1024 / 1024, free_mem[i] / 1024 / 1024);
+               total / 1024 / 1024, free / 1024 / 1024);
         auto backend = ggml_backend_dev_init(dev, nullptr);
         if (!backend) {
             fprintf(stderr, "Failed to create backend for device %s\n", dev->iface.get_name(dev));
@@ -1775,7 +1784,7 @@ void ggml_backend_rpc_start_server(const char * endpoint, const char * cache_dir
         }
         printf("Accepted client connection\n");
         fflush(stdout);
-        rpc_serve_client(backends, cache_dir, client_socket->fd, free_mem_vec, total_mem_vec);
+        rpc_serve_client(backends, cache_dir, client_socket->fd);
         printf("Client connection closed\n");
         fflush(stdout);
     }

tools/rpc/rpc-server.cpp

@@ -137,7 +137,6 @@ struct rpc_server_params {
     bool                     use_cache   = false;
     int                      n_threads   = std::max(1U, std::thread::hardware_concurrency()/2);
     std::vector<std::string> devices;
-    std::vector<size_t>      dev_mem;
 };
 
 static void print_usage(int /*argc*/, char ** argv, rpc_server_params params) {
@@ -148,7 +147,6 @@ static void print_usage(int /*argc*/, char ** argv, rpc_server_params params) {
     fprintf(stderr, "  -d, --device <dev1,dev2,...>     comma-separated list of devices\n");
     fprintf(stderr, "  -H, --host HOST                  host to bind to (default: %s)\n", params.host.c_str());
     fprintf(stderr, "  -p, --port PORT                  port to bind to (default: %d)\n", params.port);
-    fprintf(stderr, "  -m, --mem <M1,M2,...>            memory size for each device (in MB)\n");
     fprintf(stderr, "  -c, --cache                      enable local file cache\n");
     fprintf(stderr, "\n");
 }
@@ -197,23 +195,6 @@ static bool rpc_server_params_parse(int argc, char ** argv, rpc_server_params &
             }
         } else if (arg == "-c" || arg == "--cache") {
             params.use_cache = true;
-        } else if (arg == "-m" || arg == "--mem") {
-            if (++i >= argc) {
-                return false;
-            }
-            const std::regex regex{ R"([,/]+)" };
-            std::string mem_str = argv[i];
-            std::sregex_token_iterator iter(mem_str.begin(), mem_str.end(), regex, -1);
-            std::sregex_token_iterator end;
-            for ( ; iter != end; ++iter) {
-                try {
-                    size_t mem = std::stoul(*iter) * 1024 * 1024;
-                    params.dev_mem.push_back(mem);
-                } catch (const std::exception & ) {
-                    fprintf(stderr, "error: invalid memory size: %s\n", iter->str().c_str());
-                    return false;
-                }
-            }
         } else if (arg == "-h" || arg == "--help") {
             print_usage(argc, argv, params);
             exit(0);
@@ -293,18 +274,6 @@ int main(int argc, char * argv[]) {
         return 1;
     }
     std::string endpoint = params.host + ":" + std::to_string(params.port);
-    std::vector<size_t> free_mem, total_mem;
-    for (size_t i = 0; i < devices.size(); i++) {
-        if (i < params.dev_mem.size()) {
-            free_mem.push_back(params.dev_mem[i]);
-            total_mem.push_back(params.dev_mem[i]);
-        } else {
-            size_t free, total;
-            ggml_backend_dev_memory(devices[i], &free, &total);
-            free_mem.push_back(free);
-            total_mem.push_back(total);
-        }
-    }
     const char * cache_dir = nullptr;
     std::string cache_dir_str;
     if (params.use_cache) {
@@ -328,7 +297,6 @@ int main(int argc, char * argv[]) {
         return 1;
     }
 
-    start_server_fn(endpoint.c_str(), cache_dir, params.n_threads, devices.size(),
+    start_server_fn(endpoint.c_str(), cache_dir, params.n_threads, devices.size(), devices.data());
-        devices.data(), free_mem.data(), total_mem.data());
     return 0;
 }