feat: Add memory usage estimate function

Author: chenwhql

python/paddle/fluid/contrib/__init__.py

@@ -14,5 +14,7 @@
 
 import decoder
 from decoder import *
+import memory_usage_calc
+from memory_usage_calc import *
 
-__all__ = decoder.__all__
+__all__ = decoder.__all__ + memory_usage_calc.__all__

python/paddle/fluid/contrib/memory_usage_calc.py

@@ -0,0 +1,99 @@
+#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+This module privides a memory usage calculate function for user.
+The purpose of this API is to allow users to estimate memory usage of
+a program under a special batch size, then user can set appropriate 
+batch size to fully utilize a GPU. 
+
+This API is still under active development and may change drastically.
+"""
+
+from .. import core
+from ..framework import Program, Variable
+
+__all__ = ['MemoryInfo']
+
+DEBUG = False
+
+dtype_to_size = {
+    core.VarDesc.VarType.FP16: 2,
+    core.VarDesc.VarType.FP32: 4,
+    core.VarDesc.VarType.FP64: 8,
+    core.VarDesc.VarType.INT16: 2,
+    core.VarDesc.VarType.INT32: 4,
+    core.VarDesc.VarType.INT64: 8,
+    core.VarDesc.VarType.BOOL: 1,
+    core.VarDesc.VarType.UINT8: 1,
+}
+
+
+class MemoryInfo(object):
+    def __init__(self, program):
+        if not isinstance(program, Program):
+            raise TypeError(
+                "Calculating Memory Usage requires Program as its Parameter."
+                "But you passed in %s" % (type(prgram)))
+        self._program = program
+
+    def _has_var(self, block, var_name):
+        return block.has_var(str(var_name))
+
+    def _find_var(self, block, var_name):
+        return block.var(str(var_name))
+
+    def get_memory_usage(self, batch_size, with_details=False):
+
+        # get the first block of program
+        first_block = self._program.global_block()
+
+        # get the var_name list of first block
+        # TODO(chenweihang): not find the API get block's var list directly
+        total_memory = 0.0
+        for var in self._program.list_vars():
+            if DEBUG:
+                print "All Block's Var: %s" % (var.name)
+            # TODO(chenweihang): why not used program.list_vars() 
+            #                       calculate all variable's memory directly?
+            if self._has_var(first_block, var.name):
+                if DEBUG:
+                    print "First Block's Var: %s" % (var.name)
+                    print "Var's shape: ", var.shape
+                    print "Var's dtype: ", var.dtype
+                data_count = 1
+                for x in var.shape:
+                    if x == -1:
+                        data_count *= batch_size
+                    else:
+                        data_count *= x
+                var_memory = data_count * dtype_to_size[var.dtype]
+                if DEBUG:
+                    print "Var's memory: %d" % (var_memory)
+                total_memory += var_memory
+
+        # Convert unit and make result string
+        result_str = "- With current batch size, memory usage is about "
+        unit_str = " B."
+        if total_memory > 1024:
+            total_memory /= 1024
+            unit_str = " KB."
+            if total_memory > 1024:
+                total_memory /= 1024
+                unit_str = " MB."
+
+        # Append extra memory consumption (5% - 10%)
+        result_str += str(round(total_memory * 1.05, 3)) + " - " \
+                    + str(round(total_memory * 1.10, 3)) + unit_str
+
+        return result_str