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1 /* Copyright 2015 The TensorFlow Authors. All Rights Reserved.
2 
3 Licensed under the Apache License, Version 2.0 (the "License");
4 you may not use this file except in compliance with the License.
5 You may obtain a copy of the License at
6 
7     http://www.apache.org/licenses/LICENSE-2.0
8 
9 Unless required by applicable law or agreed to in writing, software
10 distributed under the License is distributed on an "AS IS" BASIS,
11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 See the License for the specific language governing permissions and
13 limitations under the License.
14 ==============================================================================*/
15 
16 #ifndef TENSORFLOW_CORE_FRAMEWORK_DEVICE_FACTORY_H_
17 #define TENSORFLOW_CORE_FRAMEWORK_DEVICE_FACTORY_H_
18 
19 #include <string>
20 #include <vector>
21 
22 #include "tensorflow/core/platform/status.h"
23 #include "tensorflow/core/platform/types.h"
24 
25 namespace tensorflow {
26 
27 class Device;
28 struct SessionOptions;
29 
30 class DeviceFactory {
31  public:
~DeviceFactory()32   virtual ~DeviceFactory() {}
33   static void Register(const std::string& device_type, DeviceFactory* factory,
34                        int priority, bool is_pluggable_device);
35   static DeviceFactory* GetFactory(const std::string& device_type);
36 
37   // Append to "*devices" CPU devices.
38   static Status AddCpuDevices(const SessionOptions& options,
39                               const std::string& name_prefix,
40                               std::vector<std::unique_ptr<Device>>* devices);
41 
42   // Append to "*devices" all suitable devices, respecting
43   // any device type specific properties/counts listed in "options".
44   //
45   // CPU devices are added first.
46   static Status AddDevices(const SessionOptions& options,
47                            const std::string& name_prefix,
48                            std::vector<std::unique_ptr<Device>>* devices);
49 
50   // Helper for tests.  Create a single device of type "type".  The
51   // returned device is always numbered zero, so if creating multiple
52   // devices of the same type, supply distinct name_prefix arguments.
53   static std::unique_ptr<Device> NewDevice(const string& type,
54                                            const SessionOptions& options,
55                                            const string& name_prefix);
56 
57   // Iterate through all device factories and build a list of all of the
58   // possible physical devices.
59   //
60   // CPU is are added first.
61   static Status ListAllPhysicalDevices(std::vector<string>* devices);
62 
63   // Iterate through all device factories and build a list of all of the
64   // possible pluggable physical devices.
65   static Status ListPluggablePhysicalDevices(std::vector<string>* devices);
66 
67   // Get details for a specific device among all device factories.
68   // 'device_index' indexes into devices from ListAllPhysicalDevices.
69   static Status GetAnyDeviceDetails(
70       int device_index, std::unordered_map<string, string>* details);
71 
72   // For a specific device factory list all possible physical devices.
73   virtual Status ListPhysicalDevices(std::vector<string>* devices) = 0;
74 
75   // Get details for a specific device for a specific factory. Subclasses
76   // can store arbitrary device information in the map. 'device_index' indexes
77   // into devices from ListPhysicalDevices.
GetDeviceDetails(int device_index,std::unordered_map<string,string> * details)78   virtual Status GetDeviceDetails(int device_index,
79                                   std::unordered_map<string, string>* details) {
80     return Status::OK();
81   }
82 
83   // Most clients should call AddDevices() instead.
84   virtual Status CreateDevices(
85       const SessionOptions& options, const std::string& name_prefix,
86       std::vector<std::unique_ptr<Device>>* devices) = 0;
87 
88   // Return the device priority number for a "device_type" string.
89   //
90   // Higher number implies higher priority.
91   //
92   // In standard TensorFlow distributions, GPU device types are
93   // preferred over CPU, and by default, custom devices that don't set
94   // a custom priority during registration will be prioritized lower
95   // than CPU.  Custom devices that want a higher priority can set the
96   // 'priority' field when registering their device to something
97   // higher than the packaged devices.  See calls to
98   // REGISTER_LOCAL_DEVICE_FACTORY to see the existing priorities used
99   // for built-in devices.
100   static int32 DevicePriority(const std::string& device_type);
101 
102   // Returns true if 'device_type' is registered from plugin. Returns false if
103   // 'device_type' is a first-party device.
104   static bool IsPluggableDevice(const std::string& device_type);
105 };
106 
107 namespace dfactory {
108 
109 template <class Factory>
110 class Registrar {
111  public:
112   // Multiple registrations for the same device type with different priorities
113   // are allowed.  Priorities are used in two different ways:
114   //
115   // 1) When choosing which factory (that is, which device
116   //    implementation) to use for a specific 'device_type', the
117   //    factory registered with the highest priority will be chosen.
118   //    For example, if there are two registrations:
119   //
120   //      Registrar<CPUFactory1>("CPU", 125);
121   //      Registrar<CPUFactory2>("CPU", 150);
122   //
123   //    then CPUFactory2 will be chosen when
124   //    DeviceFactory::GetFactory("CPU") is called.
125   //
126   // 2) When choosing which 'device_type' is preferred over other
127   //    DeviceTypes in a DeviceSet, the ordering is determined
128   //    by the 'priority' set during registration.  For example, if there
129   //    are two registrations:
130   //
131   //      Registrar<CPUFactory>("CPU", 100);
132   //      Registrar<GPUFactory>("GPU", 200);
133   //
134   //    then DeviceType("GPU") will be prioritized higher than
135   //    DeviceType("CPU").
136   //
137   // The default priority values for built-in devices is:
138   // GPU: 210
139   // GPUCompatibleCPU: 70
140   // ThreadPoolDevice: 60
141   // Default: 50
142   explicit Registrar(const std::string& device_type, int priority = 50) {
143     DeviceFactory::Register(device_type, new Factory(), priority,
144                             /*is_pluggable_device*/ false);
145   }
146 };
147 
148 }  // namespace dfactory
149 
150 #define REGISTER_LOCAL_DEVICE_FACTORY(device_type, device_factory, ...) \
151   INTERNAL_REGISTER_LOCAL_DEVICE_FACTORY(device_type, device_factory,   \
152                                          __COUNTER__, ##__VA_ARGS__)
153 
154 #define INTERNAL_REGISTER_LOCAL_DEVICE_FACTORY(device_type, device_factory, \
155                                                ctr, ...)                    \
156   static ::tensorflow::dfactory::Registrar<device_factory>                  \
157       INTERNAL_REGISTER_LOCAL_DEVICE_FACTORY_NAME(ctr)(device_type,         \
158                                                        ##__VA_ARGS__)
159 
160 // __COUNTER__ must go through another macro to be properly expanded
161 #define INTERNAL_REGISTER_LOCAL_DEVICE_FACTORY_NAME(ctr) ___##ctr##__object_
162 
163 }  // namespace tensorflow
164 
165 #endif  // TENSORFLOW_CORE_FRAMEWORK_DEVICE_FACTORY_H_
166