support reconnection

common/common.cpp

@@ -1717,6 +1717,8 @@ struct llama_init_result llama_init_from_gpt_params(gpt_params & params) {
         }
 
         // sychronize device profile to the master node
+        NodeType node_type;
+        char is_fowarder[32] = {0};
         if (my_rank == 0) {
             if (auto_schedule) {
                 std::vector<device_info> dev_info_set(n_world);
@@ -1743,14 +1745,14 @@ struct llama_init_result llama_init_from_gpt_params(gpt_params & params) {
             if (auto_schedule){
                 llama_send_device_info(lctx, &dev_info);
                 llama_recv_layer_setup(lctx, n_layer_window, n_gpu_layers);
-                llama_rebuild_topo    (lctx, n_layer_window, nullptr);
+                llama_rebuild_topo    (lctx, n_layer_window, nullptr, &node_type, is_fowarder);
             } else {
                 llama_recv_layer_setup(lctx, n_layer_window, n_gpu_layers);
             }
         }
 
         // if this is a weak device, then exit
-        if (n_layer_window[my_rank] <= 0) {
+        if (node_type == NodeType::NODE_TYPE_EXIT) {
             LOG_INF("No layer is assigned to me, exit.\n");
             llama_free(lctx);
             llama_free_model(model);
@@ -1762,7 +1764,7 @@ struct llama_init_result llama_init_from_gpt_params(gpt_params & params) {
         std::vector<uint32_t> n_layer_window_temp = {n_layer_window[0]}, n_gpu_layers_temp = {n_gpu_layers[0]};
 
         for (uint32_t i = 1; i < n_world; i++) {
-            if (n_layer_window[i] <= 0) {
+            if (n_layer_window[i] <= 0 && is_fowarder[i] == 0) {
                 continue;
             }
             if (i <= my_rank) {
@@ -1795,6 +1797,13 @@ struct llama_init_result llama_init_from_gpt_params(gpt_params & params) {
 
         llama_update_context_with_rankworld(lctx, update_rank, update_n_world);
                 
+        if(node_type == NodeType::NODE_TYPE_EXIT){
+            //just foward
+            while (true) {
+                llama_foward_messages(lctx);
+            }
+        }
+
         // update n_layer_window and n_gpu_layers
         std::copy(std::begin(n_layer_window), std::end(n_layer_window), params.n_layer_window);
         std::copy(std::begin(n_layer_window), std::end(n_layer_window), cparams.n_layer_window);

common/profiler.cpp

@@ -2621,7 +2621,7 @@ size_t serialize(const struct device_info * dev_info, char ** buffer) {
     return total_size;
 }
 
-void deserialize(const char * buffer, struct device_info * dev_info) {
+size_t deserialize(const char * buffer, struct device_info * dev_info) {
     const char * ptr = buffer;
 
     // rank
@@ -2821,6 +2821,32 @@ void deserialize(const char * buffer, struct device_info * dev_info) {
     ptr += sizeof(float);
 
     memcpy(&dev_info->gpu_props.cuda_mem_cpy_delay, ptr, sizeof(float));
+    ptr += sizeof(float);
 
     // no need to synchronize model flops and model params
+    return ptr - buffer;
+}
+
+void TopoRebuildHelperInfo::deserialize(const char *buffer) {
+    size_t buffer_size = ::deserialize(buffer, &dev_info);
+    if (buffer_size == 0) {
+        LOG_ERR("%s: failed to deserialize device info\n", __func__);
+        return;
+    }
+    memcpy(&is_fowarder, buffer + buffer_size, 1);
+}
+
+size_t TopoRebuildHelperInfo::serialize(char **buffer) const{ 
+    size_t buffer_size = ::serialize(&dev_info, buffer);
+    char* buffer_ = (char*)malloc(buffer_size+1);
+    if (buffer_ == NULL) {
+        LOG_ERR("%s: failed to allocate %zu bytes for device info serialization\n", 
+                __func__, buffer_size);
+        return 0;
+    }
+    memcpy(buffer_, *buffer, buffer_size);
+    memcpy(buffer_ + buffer_size, &is_fowarder, 1);
+    free(*buffer);
+    *buffer = buffer_;
+    return buffer_size + 1;
 }

common/profiler.h

@@ -346,6 +346,18 @@ struct device_info {
         model_bytes() {}
 };
 
+struct TopoRebuildHelperInfo{
+    struct device_info dev_info;
+    char               is_fowarder;
+    
+    TopoRebuildHelperInfo():
+        dev_info(),
+        is_fowarder(0){}
+    
+    void   deserialize(const char * buffer);
+    size_t serialize(char ** buffer) const;
+};
+
 enum profiler_backend_type {
     PROFILER_BACKEND_TYPE_CPU   = 0,
     PROFILER_BACKEND_TYPE_METAL = 1,
@@ -389,6 +401,6 @@ int      device_has_blas   (void);
 int      device_has_sycl   (void);
 
 size_t   serialize  (const struct device_info * dev_info, char ** buffer);
-void     deserialize(const char * buffer, struct device_info * dev_info);
+size_t   deserialize(const char * buffer, struct device_info * dev_info);
 
 #endif // PROFILER_H

include/llama.h

@@ -449,13 +449,24 @@ extern "C" {
 
     LLAMA_API void llama_free_model(struct llama_model * model);
     
+    enum NodeType{
+        NODE_TYPE_WORKER,
+        NODE_TYPE_FOWARDER,
+        NODE_TYPE_EXIT,
+    };
+
     LLAMA_API void llama_init_sockets      (struct llama_context * ctx, uint32_t n_world, uint32_t my_rank);
     LLAMA_API void llama_free_sockets      (struct llama_context * ctx, char ** msg);
     LLAMA_API int  llama_gather_device_info(struct llama_context * ctx, struct device_info * dev_info_set);
     LLAMA_API int  llama_send_device_info  (struct llama_context * ctx, struct device_info * dev_info);
     LLAMA_API int  llama_bcast_startup_args(struct llama_context * ctx, uint32_t rank, struct startup_args * args);
     LLAMA_API int  llama_bcast_layer_setup (struct llama_context * ctx, uint32_t * n_layer_window, uint32_t * n_gpu_layers);
-    LLAMA_API int  llama_rebuild_topo      (struct llama_context * ctx, uint32_t * n_layer_window, struct device_info * dev_info_set);
+    LLAMA_API int  llama_rebuild_topo      (struct llama_context * ctx, 
+                                                        uint32_t * n_layer_window, 
+                                              struct device_info * dev_info_set, 
+                                                         NodeType* node_type,
+                                                         char    * is_fowarder);
+    LLAMA_API int  llama_foward_messages   (struct llama_context * ctx);
     LLAMA_API int  llama_recv_layer_setup  (struct llama_context * ctx, uint32_t * n_layer_window, uint32_t * n_gpu_layers);
 
     LLAMA_API int llm_load_tensors(

src/llama.cpp

@@ -173,12 +173,12 @@ static void zeros(std::ofstream & file, size_t n) {
 }
 
 // zmq helpers
-static std::vector<zmq::message_t> dev_infos_to_messages(const device_info* infos, 
+static std::vector<zmq::message_t> topohelper_to_messages(const TopoRebuildHelperInfo* infos, 
-                                                                   uint32_t n_world){
+                                                                uint32_t n_world){
     std::vector<zmq::message_t> res;
     for (uint32_t i = 0; i < n_world; ++i) {
         char * buffer = nullptr;
-        size_t buffer_size = serialize(&infos[i], &buffer);
+        size_t buffer_size = infos[i].serialize(&buffer);
         res.emplace_back(buffer, buffer_size);
         free(buffer);
     }
@@ -20428,6 +20428,39 @@ static uint32_t map_rank_to_port(uint32_t rank, uint32_t data_port) {
     return data_port + rank;
 }
 
+static std::string try_connect(llama_context *ctx, uint32_t rank, TopoRebuildHelperInfo* infos, uint32_t n_world, zmq::socket_t** socket){
+    auto prv_rank = (rank - 1 + n_world) % n_world;
+    std::string ip = infos[prv_rank].dev_info.next_ip;
+    std::string send_endp = "tcp://" + ip + ":" + std::to_string(map_rank_to_port(rank, ctx->data_port));
+    *socket = new zmq::socket_t(*ctx->sock_context, zmq::socket_type::push);
+    int events = 0;
+    try {
+        (*socket)->set(zmq::sockopt::linger, 0);
+        (*socket)->set(zmq::sockopt::sndtimeo, 500);
+
+        (*socket)->connect(send_endp);
+
+        std::this_thread::sleep_for(std::chrono::milliseconds(500));
+
+        size_t events_size = sizeof(events);
+        (*socket)->getsockopt(ZMQ_EVENTS, &events, &events_size);
+
+    } catch (const zmq::error_t& e) {
+        delete *socket;
+        *socket = nullptr;
+        return "";
+    }
+
+    if((events & ZMQ_POLLOUT) != 0){
+        return ip;
+    }else{
+        delete *socket;
+        *socket = nullptr;
+        return "";
+    }
+    
+}
+
 void llama_init_sockets(struct llama_context * ctx, uint32_t n_world, uint32_t my_rank) {
     if (n_world == 1) {
         return; 
@@ -20602,95 +20635,161 @@ int llama_bcast_layer_setup(struct llama_context * ctx, uint32_t * n_layer_windo
     return 0;
 }
 
-int llama_rebuild_topo(llama_context * ctx, uint32_t * n_layer_window, device_info * dev_info_set) {
+int llama_rebuild_topo(llama_context * ctx,
+                            uint32_t * n_layer_window,
+                         device_info * dev_info_set,
+                            NodeType * node_type,
+                            char     * is_fowarder) {
     uint32_t n_world = ctx->cparams.n_world;
     uint32_t my_rank = ctx->cparams.rank;
-    device_info * dev_info_ptr = nullptr;
+    TopoRebuildHelperInfo* topo_helper = new TopoRebuildHelperInfo[n_world];
 
-    if (dev_info_set == nullptr) {
+    if (dev_info_set == nullptr){
+        // for rank!=0, recv all devices info
         std::vector<zmq::message_t> msgs;
         if (!zmq::recv_multipart(*ctx->recv_socket, std::back_inserter(msgs))) {
             return -1;
         }
-        dev_info_ptr = new device_info[n_world];
         for (size_t i = 0; i < msgs.size(); i++) {
-            deserialize((const char *)msgs[i].data(), &dev_info_ptr[i]);
+            topo_helper[i].deserialize((char *)msgs[i].data());
         }
         GGML_ASSERT(msgs.size() == n_world);
     } else {
-        dev_info_ptr = dev_info_set;
+        for (size_t i = 0; i < n_world; i++) {
+            topo_helper[i].dev_info = dev_info_set[i];
+            topo_helper[i].is_fowarder =  0;
+        }
     }
 
     GGML_ASSERT(ctx != nullptr && ctx->send_socket != nullptr);
 
-    // notify next rank
     auto next_rank = (my_rank + 1) % n_world;
-    if (n_layer_window[next_rank] <= 0 && next_rank != 0) {
+    auto next_connect_rank = (my_rank + 1) % n_world;
+    zmq::socket_t* socket_to_close = nullptr;
+    bool is_not_exit = n_layer_window[my_rank] > 0 || topo_helper[my_rank].is_fowarder == 1;
+    if (is_not_exit){
+        // reconstruct socket to the next valid rank
+        auto current_rank = my_rank;
+        std::vector<uint32_t> nodes;
+        auto next_rank_ = next_rank;
+        while (next_rank_ != my_rank) {
+            nodes.push_back(next_rank_);
+            if (n_layer_window[next_rank_] > 0) {
+                break;
+            }
+            next_rank_   = (next_rank_ + 1) % n_world;
+            current_rank = (current_rank + 1) % n_world;
+        }
+        if (next_rank_ == my_rank) {
+            // only one node
+            ctx->next_node_ip = "";
+            socket_to_close = ctx->send_socket;
+            ctx->send_socket = nullptr;
+        } else {
+            // iterate node reverse
+            zmq::socket_t* socket = nullptr;
+            std::string ip;
+            for (int i = nodes.size() - 1; i > 0; --i) {
+                auto rank = nodes[i];
+                ip = try_connect(ctx, rank, topo_helper, n_world, &socket);
+                if(!ip.empty()){
+                    topo_helper[rank].is_fowarder = 1;
+                    next_connect_rank = rank;
+                    break;
+                }
+            }
+            if(next_connect_rank != next_rank){
+                // reset socket
+                GGML_ASSERT(socket != nullptr);
+                GGML_ASSERT(!ip.empty());
+                socket_to_close = ctx->send_socket;
+                ctx->send_socket = socket;
+                ctx->next_node_ip = ip;
+                ctx->cparams.original_next_rank = next_connect_rank;
+            }
+        }
+    }else if(n_layer_window[next_rank] <= 0 && topo_helper[my_rank].is_fowarder == 0){
+        socket_to_close = ctx->send_socket;
+    }
+
+    // notify next exiting node
+    if (socket_to_close != nullptr) {
+        GGML_ASSERT(n_layer_window[next_rank] <= 0 && topo_helper[next_rank].is_fowarder == 0);
         try {
-            auto msgs = dev_infos_to_messages(dev_info_ptr, n_world);
+            auto msgs = topohelper_to_messages(topo_helper, n_world);
-            ctx->send_socket->set(zmq::sockopt::linger, 3500);
+            socket_to_close->set(zmq::sockopt::linger, 3500);
-            zmq::send_multipart(*ctx->send_socket, msgs);
+            zmq::send_multipart(*socket_to_close, msgs);
         } catch (const zmq::error_t& e) {
             LLAMA_LOG_INFO("Failed to send data: %s\n", e.what());
-            if(!dev_info_set){
-                delete[] dev_info_ptr;
-            }
             return -1;
         }
     }
     
-    zmq::socket_t * socket_to_close = nullptr;
+    // notify next connect node
-    if (n_layer_window[my_rank] > 0) {
+    if(!ctx->next_node_ip.empty() && is_not_exit){
-        // reconstruct socket to the next valid rank
+        GGML_ASSERT(ctx->send_socket != nullptr);
-        std::string next_ip;
+        try {
-        auto current_rank = my_rank;
+            auto msgs = topohelper_to_messages(topo_helper, n_world);
-
+            zmq::send_multipart(*ctx->send_socket, msgs);
-        while (next_rank != my_rank) {
+        } catch (const zmq::error_t& e) {
-            if (n_layer_window[next_rank] > 0) {
+            LLAMA_LOG_INFO("Failed to send data: %s\n", e.what());
-                next_ip = dev_info_ptr[current_rank].next_ip;
+            return -1;
-                break;
-            }
-            next_rank    = (next_rank    + 1) % n_world;
-            current_rank = (current_rank + 1) % n_world;
-        }
-
-        if (!next_ip.empty()) {
-            if ((my_rank + 1) % n_world != next_rank) {   
-                socket_to_close = ctx->send_socket;  
-                ctx->send_socket = new zmq::socket_t(*ctx->sock_context, zmq::socket_type::push);
-                std::string send_endp = "tcp://" + next_ip + ":" + std::to_string(map_rank_to_port(next_rank, ctx->data_port));
-                ctx->send_socket->connect(send_endp);
-                ctx->next_node_ip = next_ip;
-                ctx->cparams.original_next_rank = next_rank;
-            }
-
-            if (next_rank != 0) {
-                try {
-                    auto msgs = dev_infos_to_messages(dev_info_ptr, n_world);
-                    zmq::send_multipart(*ctx->send_socket, msgs);
-                } catch (const zmq::error_t &e) {
-                    LLAMA_LOG_INFO("Error binding/connecting recv socket to endpoint: %s", e.what());
-                    if(!dev_info_set){
-                        delete[] dev_info_ptr;
-                    }
-                    return -1;
-                }
-            }
-        } else {
-            // only one node
-            ctx->next_node_ip = "";
         }
     }
     
-    if (!dev_info_set) {
+    if(n_layer_window[my_rank] > 0){
-        delete[] dev_info_ptr;
+        *node_type = NodeType::NODE_TYPE_WORKER;
+    }else if (topo_helper[my_rank].is_fowarder == 1){
+        *node_type = NodeType::NODE_TYPE_FOWARDER;
+    }else{
+        *node_type = NodeType::NODE_TYPE_EXIT;
     }
     
+    if(ctx->send_socket != nullptr && *node_type!=NodeType::NODE_TYPE_EXIT){
+        // recv the whole view of all nodes
+        std::vector<zmq::message_t> msgs;
+        if (!zmq::recv_multipart(*ctx->recv_socket, std::back_inserter(msgs))) {
+            return -1;
+        }
+        GGML_ASSERT(msgs.size() == n_world);
+        for (size_t i = 0; i < msgs.size(); i++) {
+            topo_helper[i].deserialize((char *)msgs[i].data());
+        }
+        // broadcast the whole view
+        if(next_connect_rank!=0){
+            try {
+                zmq::send_multipart(*ctx->send_socket, msgs);
+            } catch (const zmq::error_t& e) {
+                LLAMA_LOG_INFO("Failed to send data: %s\n", e.what());
+                return -1;
+            }
+        }
+    }
+    for(size_t i = 0; i < n_world; i++) {
+        is_fowarder[i] = topo_helper[i].is_fowarder;
+    }
+
+
     if(socket_to_close != nullptr){
         socket_to_close->close();
         delete socket_to_close;
     }
+    delete [] topo_helper;
+    return 0;
+}
 
+LLAMA_API int llama_foward_messages(llama_context *ctx) {
+    zmq::message_t message;
+    bool more = true;
+    
+    while (more) {
+        ctx->recv_socket->recv(message, zmq::recv_flags::none);
+        size_t more_size = sizeof(more);
+        ctx->recv_socket->getsockopt(ZMQ_RCVMORE, &more, &more_size);
+        
+        ctx->send_socket->send(message, 
+            more ? zmq::send_flags::sndmore : zmq::send_flags::none);
+    }
     return 0;
 }