Move learning rate and releated op to pserver (PaddlePaddle#8209)

* dist train support lr decay

* update by comment

* revert elementwise method creator

* delete comment

paddle/fluid/operators/listen_and_serv_op.cc

@@ -106,6 +106,7 @@ class ListenAndServOp : public framework::OperatorBase {
       // the gradients arrives, just add suffix 0~n and merge the gradient.
       rpc_service_->SetCond(0);
       size_t recv_var_cnt = 0;
+      size_t update_param_cnt = 0;
       int batch_barrier = 0;
       while (batch_barrier != fan_in) {
         const detail::MessageWithName &v = rpc_service_->Get();
@@ -126,13 +127,14 @@ class ListenAndServOp : public framework::OperatorBase {
           std::string param_var_name;
           if (it != grad_list.end()) {
             param_var_name = param_list[it - grad_list.begin()];
+            update_param_cnt++;
+            VLOG(3) << "received grad: " << grad_var_name
+                    << " updating param: " << param_var_name;
           } else {
-            LOG(ERROR) << "grad has no paired param:" << grad_var_name;
+            VLOG(3) << "received variable: " << grad_var_name
+                    << " no need to update param";
           }
-          VLOG(3) << "received grad: " << grad_var_name
-                  << " updating param: " << param_var_name;
-
-          if (fan_in > 1) {
+          if (fan_in > 1 && !param_var_name.empty()) {
             grad_var_name = this->GetGradVarNameForTrainer(grad_var_name);
           }
           auto *var = recv_scope.FindVar(grad_var_name);
@@ -144,19 +146,18 @@ class ListenAndServOp : public framework::OperatorBase {
         }
       }
       VLOG(3) << "recv " << recv_var_cnt << " parmeters for one barrier.";
-      // TODO(Yancey1989): merge SelectedRows variables here
       if (exit_flag) {
         rpc_service_->ShutDown();
       }
-
+      VLOG(3) << "run optimize graph...";
       try {
         executor.Run(*program, &recv_scope, block->ID(), /*global_block*/
                      false /*create_local_scope*/, false /*create_vars*/);
       } catch (std::exception &e) {
         LOG(ERROR) << "run sub program error " << e.what();
       }
       rpc_service_->SetCond(1);
-      rpc_service_->WaitClientGet(recv_var_cnt);
+      rpc_service_->WaitClientGet(update_param_cnt);
       grads_counter_.clear();
     }  // while(true)
   }

python/paddle/v2/fluid/distribute_transpiler.py

@@ -33,6 +33,57 @@ def __str__(self):
         return "%s:%d:%d" % (self.varname, self.offset, self.size)
 
 
+class UnionFind(object):
+    """ Union-find data struct.
+    
+    Union-find is a data struct that keeps track of a set of elements partitioned
+    into a number of disjoint (non-overlapping) subsets.
+
+    Reference:
+    https://en.wikipedia.org/wiki/Disjoint-set_data_structure
+
+    Args:
+      elements(list): The initialize element list.
+    """
+
+    def __init__(self, elementes=None):
+        self._parents = []  # index -> parent index
+        self._index = {}  # element -> index
+        self._curr_idx = 0
+        if not elementes:
+            elementes = []
+        for ele in elementes:
+            self._parents.append(self._curr_idx)
+            self._index.update({ele: self._curr_idx})
+            self._curr_idx += 1
+
+    def find(self, x):
+        # Find the root index of given element x,
+        # execute the path compress while findind the root index
+        if not x in self._index:
+            return -1
+        idx = self._index[x]
+        while idx != self._parents[idx]:
+            t = self._parents[idx]
+            self._parents[idx] = self._parents[t]
+            idx = t
+        return idx
+
+    def union(self, x, y):
+        # Union two given element
+        x_root = self.find(x)
+        y_root = self.find(y)
+
+        if x_root == y_root:
+            return
+        self._parents[x_root] = y_root
+
+    def is_connected(self, x, y):
+        # If two given elements have the same root index,
+        # then they are connected.
+        return self.find(x) == self.find(y)
+
+
 def same_or_split_var(p_name, var_name):
     return p_name == var_name or p_name.startswith(var_name + ".block")
 
@@ -178,6 +229,21 @@ def transpile(self,
                 outputs={"Out": [orig_param]},
                 attrs={"axis": 0})
 
+        self.lr_param_mapping = self._create_lr_param_mapping()
+
+    def _create_lr_param_mapping(self):
+        lr_mapping = dict()
+        for _, opt_op in enumerate(self.optimize_ops):
+            if not opt_op.inputs or not opt_op.inputs.has_key("LearningRate") \
+              or not opt_op.inputs.has_key("Param"):
+                continue
+            lr = opt_op.inputs["LearningRate"].name
+            param = opt_op.inputs["Param"].name
+            if not lr_mapping.has_key(lr):
+                lr_mapping.update({lr: list()})
+            lr_mapping[lr].append(param)
+        return lr_mapping
+
     def _create_vars_from_blocklist(self, program, block_list):
         # Create respective variables using the block_list
         block_map = dict()
@@ -300,52 +366,15 @@ def _get_optimizer_input_shape(self, op_type, varkey, orig_shape,
             pass
         return orig_shape
 
-    def _op_input_var(self, op, varname):
-        pass
-
-    def _is_op_on_pserver(self, endpoint, all_ops, idx):
-        """
-        Recursively check if the op need to run on current server.
-        Assume that ops are in the execution order.
-        """
-        param_names = [
-            p.name for p in self.param_grad_ep_mapping[endpoint]["params"]
-        ]
-        op = all_ops[idx]
-        input_names = set(op.input_names)
-        # TODO(typhoonzero): using Param and Grad input name to identify
-        # that the operator is an optimization operator, need a better way.
-        if "Param" in input_names:
-            if op.input("Param")[0] in param_names:
-                return True
-            else:
-                for n in param_names:
-                    if same_or_split_var(n, op.input("Param")[0]) \
-                            and n != op.input("Param")[0]:
-                        return True
-                return False
-        else:
-            j = idx - 1
-            while j >= 0:
-                prev_op = all_ops[j]
-                # prev_output_names = [o.name for o in prev_op.outputs.values()]
-                # prev_input_names = [o.name for o in prev_op.inputs.values()]
-                # NOTE(typhoonzero): consider list input/output
-                prev_output_names = prev_op.desc.output_arg_names()
-                prev_input_names = prev_op.desc.input_arg_names()
-                found1 = False
-                found2 = False
-                for varname in op.desc.input_arg_names():
-                    if varname in prev_output_names:
-                        found1 = self._is_op_on_pserver(endpoint, all_ops, j)
-                # later ops may produce output for prev op's next batch use.
-                for varname in op.desc.output_arg_names():
-                    if varname in prev_input_names:
-                        found2 = self._is_op_on_pserver(endpoint, all_ops, j)
-                if found1 or found2:
-                    return True
-                j -= 1
-            return False
+    def _fetch_var_names(self, param_dict):
+        res = []
+        if not param_dict:
+            return res
+        for _, values in param_dict.iteritems():
+            if not isinstance(values, list):
+                values = [values]
+            res += [v.name for v in values]
+        return res
 
     def _append_pserver_ops(self, optimize_block, opt_op, endpoint):
         program = optimize_block.program
@@ -363,11 +392,7 @@ def _append_pserver_ops(self, optimize_block, opt_op, endpoint):
                     # do not append this op if current endpoint
                     # is not dealing with this grad block
                     return
-                merged_var = program.global_block().create_var(
-                    name=grad_block.name,
-                    persistable=grad_block.persistable,
-                    dtype=grad_block.dtype,
-                    shape=grad_block.shape)
+                merged_var = program.global_block().vars[grad_block.name]
                 # append merging ops if trainers > 1
                 if self.trainers > 1:
                     vars2merge = self._create_var_for_trainers(
@@ -398,13 +423,19 @@ def _append_pserver_ops(self, optimize_block, opt_op, endpoint):
                     shape=param_block.shape)
 
                 new_inputs[key] = tmpvar
+            elif key == "LearningRate":
+                # leraning rate variable has already be created by non-optimize op,
+                # don't create it once again.
+                new_inputs[key] = program.global_block().vars[opt_op.input(key)[
+                    0]]
 
         for key in opt_op.input_names:
-            if key in ["Param", "Grad"]:
+            new_shape = None
+            if key in ["Param", "Grad", "LearningRate"]:
                 continue
+            var = program.global_block().vars[opt_op.input(key)[0]]
             # update accumulator variable shape
             param_shape = new_inputs["Param"].shape
-            var = program.global_block().vars[opt_op.input(key)[0]]
             new_shape = self._get_optimizer_input_shape(opt_op.type, key,
                                                         var.shape, param_shape)
             tmpvar = program.global_block().create_var(
@@ -415,24 +446,22 @@ def _append_pserver_ops(self, optimize_block, opt_op, endpoint):
             new_inputs[key] = tmpvar
 
         # change output's ParamOut variable
-        outputs = self._get_output_map_from_op(program.global_block(), opt_op)
-        outputs["ParamOut"] = new_inputs["Param"]
+        opt_op.outputs["ParamOut"] = new_inputs["Param"]
         optimize_block.append_op(
             type=opt_op.type,
             inputs=new_inputs,
-            outputs=outputs,
+            outputs=opt_op.outputs,
             attrs=opt_op.attrs)
 
     def _append_pserver_non_opt_ops(self, optimize_block, opt_op):
         program = optimize_block.program
         # Append the ops for parameters that do not need to be optimized/updated
         inputs = self._get_input_map_from_op(self.program.global_block().vars,
                                              opt_op)
-        for var in inputs.itervalues():
-            if type(var) == list:
-                varlist = var
-            else:
-                varlist = [var]
+        for varlist in inputs.itervalues():
+            if not isinstance(varlist, list):
+                varlist = [varlist]
+
             for var in varlist:
                 if not program.global_block().vars.has_key(var.name):
                     program.global_block().create_var(
@@ -444,12 +473,70 @@ def _append_pserver_non_opt_ops(self, optimize_block, opt_op):
         outputs = self._get_output_map_from_op(self.program.global_block().vars,
                                                opt_op)
 
+        for varlist in outputs.itervalues():
+            if not isinstance(varlist, list):
+                varlist = [varlist]
+
+            for var in varlist:
+                program.global_block().create_var(
+                    name=var.name,
+                    persistable=var.persistable,
+                    dtype=var.dtype,
+                    shape=var.shape)
+
         optimize_block.append_op(
             type=opt_op.type,
             inputs=inputs,
             outputs=outputs,
             attrs=opt_op.attrs)
 
+    def _is_op_connected(self, op1, op2):
+        # If one op's input is another op's output or
+        # one op's output is another op's input, we say
+        # the two operator is connected.
+        op1_input_names = self._fetch_var_names(op1.inputs)
+        op1_output_names = self._fetch_var_names(op1.outputs)
+
+        op2_input_names = self._fetch_var_names(op2.inputs)
+        op2_output_names = self._fetch_var_names(op2.outputs)
+        if set(op1_output_names) & set(op2_input_names) or \
+           set(op1_input_names) & set(op2_output_names):
+            return True
+        return False
+
+    def _create_ufind(self, optimize_ops):
+        # Create a unit find data struct by optimize ops
+        ufind = UnionFind(optimize_ops)
+        for i in xrange(len(optimize_ops)):
+            for j in xrange(i, len(optimize_ops)):
+                op1 = optimize_ops[i]
+                op2 = optimize_ops[j]
+                if self._is_op_connected(op1, op2):
+                    ufind.union(op1, op2)
+        return ufind
+
+    def _is_opt_op(self, op):
+        # NOTE: It's a HACK implement.
+        # optimize op: SGDOptimize, MomentumOptimizer, AdamOptimizer and etc... 
+        if op.inputs and op.inputs.has_key("Param") \
+          and op.inputs.has_key("LearningRate"):
+            return True
+        return False
+
+    def _is_opt_op_on_pserver(self, endpoint, op):
+        param_names = [
+            p.name for p in self.param_grad_ep_mapping[endpoint]["params"]
+        ]
+        if op.inputs["Param"].name in param_names:
+            return True
+        else:
+            for n in param_names:
+                param = op.inputs["Param"].name
+                if same_or_split_var(n, param) and n != op.inputs["Param"].name:
+                    return True
+            return False
+        return False
+
     def get_pserver_program(self, endpoint):
         """
         Get pserver side program using the endpoint
@@ -469,26 +556,37 @@ def get_pserver_program(self, endpoint):
             pserver_program.global_block().create_var(
                 name=v.name, persistable=True, dtype=v.dtype, shape=v.shape)
             for trainer_id in xrange(self.trainers):
-                print("create variable for program: %s.trainer_%d" %
-                      (v.name, trainer_id))
                 pserver_program.global_block().create_var(
                     name="%s.trainer_%d" % (v.name, trainer_id),
                     persistable=True,
                     dtype=v.dtype,
                     shape=v.shape)
         # step6
         optimize_block = pserver_program.create_block(0)
-        # Iterate through the ops and append ops as needed
-        for idx, opt_op in enumerate(self.optimize_ops):
-            is_op_on_pserver = self._is_op_on_pserver(endpoint,
-                                                      self.optimize_ops, idx)
-            if not is_op_on_pserver:
-                continue
-            if "Grad" in opt_op.desc.input_arg_names():
-                self._append_pserver_ops(optimize_block, opt_op, endpoint)
-            else:
-                self._append_pserver_non_opt_ops(optimize_block, opt_op)
-
+        # step 6.1
+        # Create a union-find data struct by optimize ops,
+        # If two ops are connected, we could add these two ops
+        # into one set.
+        ufind = self._create_ufind(self.optimize_ops)
+        # step 6.2 
+        # Iterate through the ops and append optimize op which
+        # located on current pserver
+        opt_op_on_pserver = []
+        for _, op in enumerate(self.optimize_ops):
+            if self._is_opt_op(op) and self._is_opt_op_on_pserver(endpoint, op):
+                opt_op_on_pserver.append(op)
+        # step 6.3
+        # Iterate through the ops, and if an op and the optimize ops
+        # which located on current pserver are in one set, then 
+        # append it into the sub program.
+        for _, op in enumerate(self.optimize_ops):
+            for _, opt_op in enumerate(opt_op_on_pserver):
+                if ufind.is_connected(op, opt_op):
+                    if self._is_opt_op(op):
+                        self._append_pserver_ops(optimize_block, op, endpoint)
+                    else:
+                        self._append_pserver_non_opt_ops(optimize_block, op)
+                    break
         # Append the listen_and_serv op
         pserver_program.global_block().append_op(
             type="listen_and_serv",

python/paddle/v2/fluid/layers/math_op_patch.py

@@ -117,6 +117,7 @@ def __impl__(self, other_var):
 
             tmp_name = unique_tmp_name()
             out = self.block.create_var(name=tmp_name, dtype=lhs_dtype)
+
             self.block.append_op(
                 type=op_type,
                 inputs={'X': [self],

python/paddle/v2/fluid/tests/book_distribute/notest_dist_word2vec.py

@@ -99,7 +99,7 @@
     exe.run(fluid.default_startup_program())
     for pass_id in range(PASS_NUM):
         for data in train_reader():
-            avg_cost_np = exe.run(fluid.default_main_program(),
+            avg_cost_np = exe.run(t.get_trainer_program(),
                                   feed=feeder.feed(data),
                                   fetch_list=[avg_cost])
             print("avg_cost_np", avg_cost_np)