split tensor to pservers

python/paddle/v2/fluid/distribute_transpiler.py

@@ -4,6 +4,7 @@ from framework import Program, default_main_program, Parameter, Variable
 import optimizer
 from layer_helper import LayerHelper
 from distributed_spliter import *
+import math
 
 
 class VarBlock:
@@ -17,6 +18,47 @@ class VarBlock:
         return "%s:%d:%d" % (self.varname, self.offset, self.size)
 
 
+def split_dense_variable(var_list,
+                         pserver_count,
+                         min_block_size=1024,
+                         max_block_size=1048576):
+    """
+        We may need to split dense tensor to one or several blocks and put
+        them equally onto parameter server. One block is a sub-tensor
+        aligned by dim[0] of the tensor.
+        
+        We need to have a minimal block size so that the calculations in
+        the parameter server side can gain better performance. By default
+        mininum block size is 1024. The max block size is used to prevent
+        too large block that may causing send error.
+    """
+    blocks = []
+    for var in var_list:
+        split_count = pserver_count
+        var_numel = reduce(lambda x, y: x * y, var.shape)
+        max_pserver_count = int(math.floor(var_numel / float(min_block_size)))
+        if max_pserver_count == 0:
+            max_pserver_count = 1
+        if max_pserver_count < pserver_count:
+            split_count = max_pserver_count
+        block_size = int(math.ceil(var_numel / float(split_count)))
+
+        if len(var.shape) >= 2:
+            # align by dim1(width)
+            dim1 = reduce(lambda x, y: x * y, var.shape[1:])
+            remains = block_size % dim1
+            if remains != 0:
+                block_size += dim1 - remains
+        # update split_count after align
+        split_count = int(math.ceil(var_numel / float(block_size)))
+        for block_id in xrange(split_count):
+            curr_block_size = min(block_size, var_numel - (
+                (block_id) * block_size))
+            block = VarBlock(var.name, block_id, curr_block_size)
+            blocks.append(str(block))
+    return blocks
+
+
 class DistributeTranspiler:
     def transpile(self,
                   optimize_ops,
@@ -57,43 +99,49 @@ class DistributeTranspiler:
         # 5. create parameter server program by split_method generated endpoint->VarBlock
         # 6. run compile time infershape for parameter server program
 
-        if kwargs.has_key("split_method"):
-            split_method = kwargs["split_method"]
-        else:
-            split_method = round_robin
-        pserver_endpoints = kwargs["pservers"].split(",")
-
-        grad2param = dict()
-        for param, grad in params_and_grads:
-            grad2param[grad.name()] = param.name()
+        pserver_endpoints = pservers.split(",")
 
         # step1
-        param_list = [pg[0] for pg in params_and_grads]
-        grad_list = [pg[1] for pg in params_and_grads]
+        param_list = [pg[0] for pg in params_grads]
+        grad_list = [pg[1] for pg in params_grads]
         # TODO: add split selected rows support
-        grad_blocks = _split_dense_variable(grad_list, len(pserver_endpoints))
-        param_blocks = _split_dense_variable(param_list, len(pserver_endpoints))
-        ep2gradblock = split_method(grad_blocks, pserver_endpoints)
-        # self.param_grad_map
+        grad_blocks = split_dense_variable(grad_list, len(pserver_endpoints))
+        param_blocks = split_dense_variable(param_list, len(pserver_endpoints))
         # step2
-        var2splited = self._split_trainer_vars(program, grad_blocks)
+        grad_var_mapping = self._append_split_op(program, grad_blocks)
 
         # step3
         send_inputs = []
-        for _, splited in var2splited.iteritems():
+        send_outputs = []
+        for _, splited in grad_var_mapping.iteritems():
             send_inputs.extend(splited)
-        send_outputs = self._create_vars_from_blocklist(program, param_blocks)
+        param_var_mapping = self._create_vars_from_blocklist(program,
+                                                             param_blocks)
+        for _, splited in param_var_mapping.iteritems():
+            send_outputs.extend(splited)
+        # let send_op know which endpoint to send which var, eplist is of the same
+        # order of send_inputs.
+        eplist = split_method(send_inputs, pserver_endpoints)
 
         send_op = program.global_block().append_op(
             type="send",
             inputs={"X": send_inputs},
             outputs={"Out": send_outputs},
             attrs={"endpoints": pserver_endpoints,
-                   "epmap": epmap})
+                   "epmap": eplist})
+
+        # step4
+        for varname, splited_var in param_var_mapping.iteritems():
+            orig_param = program.global_block().vars[varname]
+            concat = program.global_block().append_op(
+                type="concat",
+                inputs={"X": send_outputs},
+                outputs={"Out": orig_param},
+                attrs={"axis": 0})
 
     def _create_vars_from_blocklist(self, program, block_list):
         block_map = dict()
-        ret_vars = []
+        var_mapping = dict()
         for block_str in block_list:
             varname, offset, size = block_str.split(":")
             if not block_map.has_key(varname):
@@ -102,15 +150,26 @@ class DistributeTranspiler:
 
         for varname, splited in block_map.iteritems():
             orig_var = program.global_block().vars[varname]
-            for block in splited:
+            orig_shape = orig_var.shape
+            orig_dim1_flatten = 1
+            if len(orig_shape) >= 2:
+                orig_dim1_flatten = reduce(lambda x, y: x * y, orig_shape[1:])
+            var_list = []
+            for i, block in enumerate(splited):
                 size = block[1]
+                rows = size / orig_dim1_flatten
+                splited_shape = [rows]
+                if len(orig_shape) >= 2:
+                    splited_shape.extend(orig_shape[1:])
+                print("block, splited shape:", block, splited_shape)
                 var = program.global_block().create_var(
                     name="%s.block%d" % (varname, i),
                     psersistable=False,
                     dtype=orig_var.dtype,
-                    shape=[1, size])  # flattend splited var
-                ret_vars.append(var)
-        return ret_vars
+                    shape=splited_shape)  # flattend splited var
+                var_list.append(var)
+            var_mapping[varname] = var_list
+        return var_mapping
 
     def _clone_param(self, block, v):
         assert isinstance(v, Parameter)
@@ -137,80 +196,22 @@ class DistributeTranspiler:
             lod_level=var.lod_level,
             persistable=var.persistable)
 
-    def _split_dense_variable(self,
-                              var_list,
-                              pserver_count,
-                              min_block_size=1024,
-                              max_block_size=1048576):
-        """
-            We may need to split dense tensor to one or several blocks and put
-            them equally onto parameter server. One block is a sub-tensor
-            aligned by dim[0] of the tensor.
-            
-            We need to have a minimal block size so that the calculations in
-            the parameter server side can gain better performance. By default
-            mininum block size is 1024. The max block size is used to prevent
-            too large block that may causing send error.
-        """
-        block_sizes = []
-        blocks = []
-        for grad in var_list:
-            dim1 = reduce(lambda x, y: x * y, grad.shape[1:])
-            grad_numel = reduce(lambda x, y: x * y, grad.shape)
-            if grad_numel < min_block_size:
-                block_sizes.append(grad_numel)
-            block_size = grad_numel / min_block_size
-            if block_size < min_block_size:
-                block_size = min_block_size
-            # align by dim1(width)
-            remains = block_size % dim1
-            if remains != 0:
-                block_size += dim1 - remains
-            block_sizes.append(block_size)
-            num_blocks = grad_numel / block_size
-            print("grad numel :%d, blocksize: %d" % grad_numel, block_size)
-            for block_id in xrange(num_blocks):
-                block = VarBlock(grad.name(), block_id, block_size)
-                blocks.append(str(block))
-        return blocks
-
-    def _split_trainer_vars(self, program, gradblocks, params_and_grads):
-        var2blocks = dict()
-        splited = dict()
-        for block_str in gradblocks:
-            varname, offset, size = block_str.split(":")
-            if not var2blocks.has_key(varname):
-                var2blocks[varname] = []
-            var2blocks[varname].append((long(offset), long(size)))
-        for varname, blocks in var2blocks.iteritems():
+    def _append_split_op(self, program, gradblocks):
+        var_mapping = self._create_vars_from_blocklist(program, gradblocks)
+        for varname, splited_vars in var_mapping.iteritems():
+            if len(splited_vars) == 1:
+                continue
             orig_var = program.global_block().vars[varname]
-            split_outs = []
-            for i in xrange(len(blocks)):
-                size = blocks[i][1]
-                var = program.global_block().create_var(
-                    name="%s.block%d" % (varname, i),
-                    psersistable=False,
-                    dtype=orig_var.dtype,
-                    shape=[1, size])  # flattend splited var
-                split_outs.append(var)
-
-            splited[varname] = split_outs
+            sections = []
+            for v in splited_vars:
+                sections.append(v.shape[0])
             program.global_block().append_op(
                 type="split",
                 inputs={"X": orig_var},
-                outputs={"Out": split_outs},
-                attrs={"num": len(blocks)}  # assume split evenly
+                outputs={"Out": splited_vars},
+                attrs={"sections": sections}  # assume split evenly
             )
-        return splited
-
-    def _concat_trainer_vars(self, program, splited):
-        for varname, to_merge_list in splited.iteritems():
-            orig_var = program.global_block().vars[varname]
-            program.global_block().append_op(
-                type="concat",
-                inputs={"X": to_merge_list},
-                outputs={"Out": orig_var},
-                attrs={})
+        return var_mapping
 
     def get_trainer_program(self):
         # remove optimize ops and add a send op to main_program

python/paddle/v2/fluid/distribute_transpiler_simple.py

@@ -0,0 +1,242 @@
+import framework
+from framework import Program, default_main_program, Parameter, Variable
+import optimizer
+from layer_helper import LayerHelper
+
+
+def hash_name_to_server(params_grads, pserver_endpoints):
+    """
+    :param param_grads:
+    :return: a map of pserver endpoint -> 
+                    params -> [param list]
+                    grads  -> [grad list]
+    """
+
+    def _hash_param(param_name, total):
+        return hash(param_name) % total
+
+    param_grad_map = dict()
+    for param, grad in params_grads:
+        if param.trainable is True and grad is not None:
+            server_id = _hash_param(param.name, len(pserver_endpoints))
+            server_for_param = pserver_endpoints[server_id]
+            if not param_grad_map.has_key(server_for_param):
+                param_grad_map[server_for_param] = {"params": [], "grads": []}
+            param_grad_map[server_for_param]["params"].append(param)
+            param_grad_map[server_for_param]["grads"].append(grad)
+
+    return param_grad_map
+
+
+def round_robin(params_grads, pserver_endpoints):
+    assert (len(params_grads) > len(pserver_endpoints))
+
+    param_grad_map = dict()
+    pserver_idx = 0
+    for param, grad in params_grads:
+        if param.trainable is True:
+            server_for_param = pserver_endpoints[pserver_idx]
+            if not param_grad_map.has_key(server_for_param):
+                param_grad_map[server_for_param] = {"params": [], "grads": []}
+
+            param_grad_map[server_for_param]["params"].append(param)
+            param_grad_map[server_for_param]["grads"].append(grad)
+
+            pserver_idx += 1
+            if pserver_idx >= len(pserver_endpoints):
+                pserver_idx = 0
+    return param_grad_map
+
+
+class DistributeTranspiler:
+    def transpile(self,
+                  optimize_ops,
+                  params_grads,
+                  program=None,
+                  pservers="127.0.0.1:6174",
+                  trainers=1,
+                  split_method=round_robin):
+        """
+            Transpile the program to a distributed data-parallelism programs.
+
+            The main_program will be transform to use a remote parameter server
+            to do parameter optimization. And the optimization graph will be put
+            in to a parameter server program.
+
+            Use different methods to split trainable varialbles to different
+            parameter servers.
+
+            Example to run:
+
+            exe = fluid.Executor(place)
+            t = fluid.DistributeTranspiler()
+            t.transpile(optimize_ops, params_grads, pservers="127.0.0.1:6174", trainers=1)
+
+            pserver_endpoint = os.getenv("PSERVER")
+            if pserver_endpoint:
+                pserver_prog = t.get_pserver_program(pserver_endpoint, optimize_ops)
+                exe.run(fluid.default_startup_program())
+                exe.run(pserver_prog)
+            else:
+                feeder = fluid.DataFeeder(feed_list=[images, label], place=place)
+                exe.run(fluid.default_startup_program())
+
+                for pass_id in range(PASS_NUM):
+                    ...
+
+            :param optimize_ops: op list of optimization, should be the
+                                 return value of Optimizer.minimize
+            :type optimize_ops: list
+            :param program: program to optimize, default default_main_program
+            :param pservers: parameter server endpoints like "m1:6174,m2:6174"
+            :type pservers: string
+
+            :return: return a list of programs
+        """
+        if program is None:
+            program = default_main_program()
+        self.program = program
+        self.trainers = trainers
+        self.optimize_ops = optimize_ops
+        self._optimize_distributed(
+            optimize_ops,
+            program,
+            params_grads,
+            pservers=pservers,
+            trainers=trainers,
+            split_method=split_method)
+
+    def _clone_param(self, block, v):
+        assert isinstance(v, Parameter)
+        new_p = Parameter(
+            block=block,
+            shape=v.shape,
+            dtype=v.dtype,
+            type=v.type,
+            lod_level=v.lod_level,
+            stop_gradient=v.stop_gradient,
+            trainable=v.trainable,
+            optimize_attr=v.optimize_attr,
+            regularizer=v.regularizer,
+            name=v.name)
+        block.vars[new_p.name] = new_p
+
+    def _clone_var(self, block, var):
+        assert isinstance(var, Variable)
+        return block.create_var(
+            name=var.name,
+            shape=var.shape,
+            dtype=var.dtype,
+            type=var.type,
+            lod_level=var.lod_level,
+            persistable=var.persistable)
+
+    def _optimize_distributed(self, optimize_ops, program, params_and_grads,
+                              **kwargs):
+        if kwargs.has_key("split_method"):
+            split_method = kwargs["split_method"]
+        else:
+            split_method = round_robin
+
+        assert (callable(split_method))
+        pserver_endpoints = kwargs["pservers"].split(",")
+        self.param_grad_map = split_method(params_and_grads, pserver_endpoints)
+
+        send_op_ordered_inputs = []
+        send_op_ordered_outputs = []
+        epmap = []
+        for ep, v in self.param_grad_map.iteritems():
+            send_op_ordered_inputs.extend(v["grads"])
+            send_op_ordered_outputs.extend(v["params"])
+            for i in v["grads"]:
+                epmap.append(ep)
+        send_op = program.global_block().append_op(
+            type="send",
+            inputs={"X": send_op_ordered_inputs
+                    },  # inputs is a list of tensors to be send
+            outputs={"Out": send_op_ordered_outputs},
+            attrs={"endpoints": pserver_endpoints,
+                   "epmap": epmap})
+
+    def get_trainer_program(self):
+        # remove optimize ops and add a send op to main_program
+        self.program.global_block().delete_ops(self.optimize_ops)
+        return self.program
+
+    def _create_var_for_trainers(self, block, var, trainers):
+        var_list = []
+        for i in xrange(trainers):
+            var_each = block.create_var(
+                name="%s.trainer_%d" % (var.name, i),
+                psersistable=var.persistable,
+                dtype=var.dtype,
+                shape=var.shape)
+            var_list.append(var_each)
+        return var_list
+
+    def get_pserver_program(self, endpoint, optimize_ops):
+        pserver_program = Program()
+        for v in self.param_grad_map[endpoint]["params"]:
+            self._clone_param(pserver_program.global_block(), v)
+
+        optimize_sub_program = Program()
+        grad_var_names = [
+            var.name for var in self.param_grad_map[endpoint]["grads"]
+        ]
+        for opt_op in optimize_ops:
+            for _, var in opt_op.inputs.iteritems():
+                # NOTE: append operators to merge gradients from multiple
+                # trainers. If trainers == 1, this is not needed.
+                if self.trainers > 1 and var.name in grad_var_names:
+                    vars2merge = self._create_var_for_trainers(
+                        optimize_sub_program.global_block(), var, self.trainers)
+                    merged_var = optimize_sub_program.global_block().create_var(
+                        name=var.name,
+                        persistable=var.persistable,
+                        dtype=var.dtype,
+                        shape=var.shape)
+                    optimize_sub_program.global_block().append_op(
+                        type="sum",
+                        inputs={"X": vars2merge},
+                        outputs={"Out": merged_var})
+                    optimize_sub_program.global_block().append_op(
+                        type="scale",
+                        inputs={"X": merged_var},
+                        outputs={"Out": merged_var},
+                        attrs={"scale": 1.0 / float(self.trainers)})
+                else:
+                    optimize_sub_program.global_block().create_var(
+                        name=var.name,
+                        persistable=var.persistable,
+                        dtype=var.dtype,
+                        shape=var.shape)
+
+            if opt_op.inputs.has_key("Grad"):
+                if opt_op.inputs["Grad"].name in grad_var_names:
+                    optimize_sub_program.global_block().append_op(
+                        type=opt_op.type,
+                        inputs=opt_op.inputs,
+                        outputs=opt_op.outputs,
+                        attrs=opt_op.attrs)
+            else:
+                optimize_sub_program.global_block().append_op(
+                    type=opt_op.type,
+                    inputs=opt_op.inputs,
+                    outputs=opt_op.outputs,
+                    attrs=opt_op.attrs)
+        pserver_program.global_block().append_op(
+            type="recv",
+            inputs={"RX":
+                    self.param_grad_map[endpoint]["grads"]},  # grads to recv
+            outputs={},
+            attrs={
+                "OptimizeProgram": optimize_sub_program.desc,
+                "endpoint": endpoint,
+                "ParamList":
+                [p.name for p in self.param_grad_map[endpoint]["params"]],
+                "GradList":
+                [p.name for p in self.param_grad_map[endpoint]["grads"]],
+                "Trainers": self.trainers
+            })
+        pserver_program.sync_with_cpp()
+        return pserver_program

python/paddle/v2/fluid/distributed_spliter.py

@@ -1,38 +1,35 @@
-def hash_name(varblocks, pserver_endpoints):
+def hash_name(varlist, pserver_endpoints):
     """
-    :param varblocks: a list of VarBlock string indicating 
-                      sub blocks of variables
-    :return: a map of pserver endpoint -> varblock_str
+    hash variable names to several endpoints.
+
+    :param varlist: a list of Variables
+    :return: a map of pserver endpoint -> varname
     """
 
     def _hash_block(block_str, total):
         return hash(block_str) % total
 
-    ep2block = dict()
-    for varblock_str in varblocks:
-        if param.trainable is True and grad is not None:
-            server_id = _hash_block(varblock_str, len(pserver_endpoints))
+    eplist = []
+    for var in varlist:
+        server_id = _hash_block(var.name(), len(pserver_endpoints))
         server_for_param = pserver_endpoints[server_id]
-            if not ep2block.has_key(server_for_param):
-                ep2block[server_for_param] = []
-            ep2block[server_for_param].append(varblock_str)
-
-    return ep2block
+        eplist.append(server_for_param)
+    return eplist
 
 
-def round_robin(varblocks, pserver_endpoints):
-    assert (len(varblocks) > len(pserver_endpoints))
+def round_robin(varlist, pserver_endpoints):
+    """
+    distribute variables to several endpoints.
+    """
+    assert (len(varlist) > len(pserver_endpoints))
 
-    ep2block = dict()
+    eplist = []
     pserver_idx = 0
-    for varblock_str in varblocks:
-        if param.trainable is True:
+    for var in varlist:
         server_for_param = pserver_endpoints[pserver_idx]
-            if not ep2block.has_key(server_for_param):
-                ep2block[server_for_param] = []
-            ep2block[server_for_param].append(varblock_str)
+        eplist.append(server_for_param)
 
         pserver_idx += 1
         if pserver_idx >= len(pserver_endpoints):
             pserver_idx = 0
-    return ep2block
+    return eplist

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

@@ -0,0 +1,38 @@
+import math
+import unittest
+from paddle.v2.fluid.distribute_transpiler import split_dense_variable
+import paddle.v2.fluid as fluid
+import random
+
+
+class TestSplitVar(unittest.TestCase):
+    def test_check_output(self):
+        # split below shapes to 10 servers
+        shapes = [[3, 5], [1024], [28, 784], [8, 1020], [800, 10]]
+        expected_sizes = [
+            [15], [1024],
+            [2352, 2352, 2352, 2352, 2352, 2352, 2352, 2352, 2352, 784],
+            [2040, 2040, 2040, 2040],
+            [1150, 1150, 1150, 1150, 1150, 1150, 1100]
+        ]
+        var_list = []
+        program = fluid.Program()
+        for shape in shapes:
+            var = program.global_block().create_var(
+                name=str(random.randint(10000)),
+                persistable=True,
+                dtype=core.VarDesc.VarType.LOD_TENSOR,
+                shape=shape)
+            var_list.append(var)
+        blocks = split_dense_variable(var_list, 10)
+        all_sizes = []
+        for s in expected_sizes:
+            for s2 in s:
+                all_sizes.append(s2)
+        for i, block_str in enumerate(blocks):
+            varname, block_id, size = block_str.split(":")
+            self.assertEqual(int(size), all_sizes[i])
+
+
+if __name__ == '__main__':
+    unittest.main()