aysnc send/recv, seriliaze/deserialize using threadpool. (#7705)

* aysnc send/recv, seriliaze/deserialize using threadpool

* implement paralell deserialization correctly

paddle/operators/detail/grpc_client.cc

@@ -13,6 +13,7 @@ See the License for the specific language governing permissions and
 limitations under the License. */
 
 #include "grpc_client.h"
+#include "paddle/framework/threadpool.h"
 namespace paddle {
 namespace operators {
 namespace detail {
@@ -22,25 +23,32 @@ bool RPCClient::AsyncSendVariable(const std::string& ep,
                                   const framework::Scope& scope,
                                   const std::string& var_name,
                                   int64_t time_out) {
-  sendrecv::VariableMessage req;
-  auto* var = scope.FindVar(var_name);
-  SerializeToMessage(var_name, var, ctx, &req);
-
-  // varhandle
-  VarHandle var_h;
-  var_h.ep = ep;
-  var_h.scope = &scope;
-  var_h.name = var_name;
-  var_h.ctx = &ctx;
-
-  // stub context
-  auto ch = GetChannel(ep);
-  SendProcessor* s = new SendProcessor(ch);
-  s->Prepare(var_h, time_out);
-  s->response_call_back_ = NULL;
-
-  auto rpc = s->stub_->AsyncSendVariable(s->context_.get(), req, &cq_);
-  rpc->Finish(&s->reply_, &s->status_, (void*)s);
+  const platform::DeviceContext* p_ctx = &ctx;
+  const std::string ep_val = ep;
+  const std::string var_name_val = var_name;
+  const framework::Scope* p_scope = &scope;
+  const auto ch = GetChannel(ep_val);
+
+  framework::Async([var_name_val, p_ctx, ep_val, p_scope, time_out, ch, this] {
+    auto* var = p_scope->FindVar(var_name_val);
+    sendrecv::VariableMessage req;
+    SerializeToMessage(var_name_val, var, *p_ctx, &req);
+
+    // varhandle
+    VarHandle var_h;
+    var_h.ep = ep_val;
+    var_h.scope = p_scope;
+    var_h.name = var_name_val;
+    var_h.ctx = p_ctx;
+
+    // stub context
+    SendProcessor* s = new SendProcessor(ch);
+    s->Prepare(var_h, time_out);
+    s->response_call_back_ = NULL;
+
+    auto rpc = s->stub_->AsyncSendVariable(s->context_.get(), req, &cq_);
+    rpc->Finish(&s->reply_, &s->status_, (void*)s);
+  });
 
   req_count_++;
 
@@ -50,8 +58,6 @@ bool RPCClient::AsyncSendVariable(const std::string& ep,
 void ProcGetResponse(const VarHandle& var_h,
                      const sendrecv::VariableMessage& ret_msg) {
   auto* outvar = var_h.scope->FindVar(var_h.name);
-
-  std::istringstream iss(ret_msg.serialized());
   DeserializeFromMessage(ret_msg, *var_h.ctx, outvar);
 }
 
@@ -60,24 +66,31 @@ bool RPCClient::AsyncGetVariable(const std::string& ep,
                                  const framework::Scope& scope,
                                  const std::string& var_name,
                                  int64_t time_out) {
-  sendrecv::VariableMessage req;
-  req.set_varname(var_name);
-
-  // varhandle
-  VarHandle var_h;
-  var_h.ep = ep;
-  var_h.scope = &scope;
-  var_h.name = var_name;
-  var_h.ctx = &ctx;
-
-  // stub context
-  auto ch = GetChannel(ep);
-  GetProcessor* s = new GetProcessor(ch);
-  s->Prepare(var_h, time_out);
-  s->response_call_back_ = ProcGetResponse;
-
-  auto rpc = s->stub_->AsyncGetVariable(s->context_.get(), req, &cq_);
-  rpc->Finish(&s->reply_, &s->status_, (void*)s);
+  const platform::DeviceContext* p_ctx = &ctx;
+  const std::string ep_val = ep;
+  const std::string var_name_val = var_name;
+  const framework::Scope* p_scope = &scope;
+  const auto ch = GetChannel(ep_val);
+
+  framework::Async([var_name_val, ep_val, p_scope, p_ctx, time_out, ch, this] {
+    sendrecv::VariableMessage req;
+    req.set_varname(var_name_val);
+
+    // varhandle
+    VarHandle var_h;
+    var_h.ep = ep_val;
+    var_h.scope = p_scope;
+    var_h.name = var_name_val;
+    var_h.ctx = p_ctx;
+
+    // stub context
+    GetProcessor* s = new GetProcessor(ch);
+    s->Prepare(var_h, time_out);
+    s->response_call_back_ = ProcGetResponse;
+
+    auto rpc = s->stub_->AsyncGetVariable(s->context_.get(), req, &cq_);
+    rpc->Finish(&s->reply_, &s->status_, (void*)s);
+  });
 
   req_count_++;
 
@@ -85,19 +98,31 @@ bool RPCClient::AsyncGetVariable(const std::string& ep,
 }
 
 bool RPCClient::Wait() {
-  bool ok = true;
+  if (req_count_ <= 0) {
+    return true;
+  }
 
-  while (true) {
-    if (req_count_ <= 0) {
-      break;
-    }
+  std::vector<bool> a(req_count_);
+  std::vector<std::future<void>> waits(req_count_);
 
-    if (!Proceed()) {
+  for (int i = 0; i < req_count_; i++) {
+    waits[i] = framework::Async([i, &a, this] { a[i] = Proceed(); });
+  }
+
+  for (int i = 0; i < req_count_; i++) {
+    waits[i].wait();
+  }
+
+  int last_req_count = req_count_;
+  req_count_ = 0;
+
+  for (int i = 0; i < last_req_count; i++) {
+    if (!a[i]) {
       return false;
     }
   }
 
-  return ok;
+  return true;
 }
 
 bool RPCClient::Proceed() {
@@ -124,7 +149,6 @@ bool RPCClient::Proceed() {
 
   c->Process();
   delete c;
-  req_count_--;
   return true;
 }