Set expected place in child thread for dataloader to avoid costing cuda memory on other card

paddle/fluid/pybind/imperative.cc

@@ -161,7 +161,7 @@ static void InitVarBaseFromNumpyWithArg(imperative::VarBase *self,
   }
   VLOG(5) << "Init Tensor as: / name: " << name
           << " / persistable: " << persistable << " / zero_copy: " << zero_copy
-          << " / stop_gradient: " << stop_gradient;
+          << " / stop_gradient: " << stop_gradient << " / at " << place;
   new (self) imperative::VarBase(name);
   self->SetPersistable(persistable);
   auto *tensor = self->MutableVar()->GetMutable<framework::LoDTensor>();
@@ -175,8 +175,8 @@ static void InitVarBaseFromNumpyWithArg(imperative::VarBase *self,
 
 static void InitVarBaseFromNumpyWithArgDefault(imperative::VarBase *self,
                                                const py::array &array) {
-  VLOG(4) << "Init VarBase from numpy: ";
   auto place = imperative::GetCurrentTracer()->ExpectedPlace();
+  VLOG(4) << "Init VarBase from numpy at " << place;
   InitTensorForVarBase(self, array, place);
 }
 
@@ -1206,15 +1206,44 @@ void BindImperative(py::module *m_ptr) {
             if (py::isinstance<platform::CUDAPlace>(obj)) {
               auto p = obj.cast<platform::CUDAPlace *>();
               self.SetExpectedPlace(*p);
+
+// NOTE(zhiqiu): When switching cuda place, we need to set the
+// cuda device id.
+// Otherwise, some cuda API may be launched at other cuda place,
+// which may cost hundreds of MB of GPU memory due to the cuda
+// lib.
+#ifdef PADDLE_WITH_CUDA
+              platform::SetDeviceId(p->device);
+#endif
+              VLOG(4) << "Tracer(" << &self << ")"
+                      << " set expected place " << *p;
             } else if (py::isinstance<platform::XPUPlace>(obj)) {
               auto p = obj.cast<platform::XPUPlace *>();
               self.SetExpectedPlace(*p);
+              VLOG(4) << "Tracer(" << &self << ")"
+                      << " set expected place " << *p;
             } else if (py::isinstance<platform::CPUPlace>(obj)) {
               auto p = obj.cast<platform::CPUPlace *>();
               self.SetExpectedPlace(*p);
+              VLOG(4) << "Tracer(" << &self << ")"
+                      << " set expected place " << *p;
             } else if (py::isinstance<platform::CUDAPinnedPlace>(obj)) {
               auto p = obj.cast<platform::CUDAPinnedPlace *>();
               self.SetExpectedPlace(*p);
+              VLOG(4) << "Tracer(" << &self << ")"
+                      << " set expected place " << *p;
+            } else if (py::isinstance<platform::Place>(obj)) {
+              auto p = obj.cast<platform::Place *>();
+              self.SetExpectedPlace(*p);
+              if (platform::is_gpu_place(*p)) {
+// NOTE(zhiqu): same as obj is CUDAPlace.
+#ifdef PADDLE_WITH_CUDA
+                platform::SetDeviceId(
+                    BOOST_GET_CONST(platform::CUDAPlace, *p).device);
+#endif
+              }
+              VLOG(4) << "Tracer(" << &self << ")"
+                      << " set expected place " << *p;
             } else {
               PADDLE_THROW(platform::errors::InvalidArgument(
                   "Incompatible Place Type: supports XPUPlace, CUDAPlace, "

paddle/fluid/pybind/tensor_py.h

@@ -288,12 +288,14 @@ void SetTensorFromPyArrayT(
 #endif
   } else {
 #ifdef PADDLE_WITH_CUDA
-    auto dst = self->mutable_data<T>(place);
-    if (paddle::platform::is_cuda_pinned_place(place)) {
-      std::memcpy(dst, array.data(), array.nbytes());
-    } else if (paddle::platform::is_gpu_place(place)) {
+    if (paddle::platform::is_gpu_place(place)) {
+      // TODO(zhiqiu): set SetDeviceId before calling cuda APIs.
+      auto dst = self->mutable_data<T>(place);
       paddle::platform::GpuMemcpySync(dst, array.data(), array.nbytes(),
                                       cudaMemcpyHostToDevice);
+    } else if (paddle::platform::is_cuda_pinned_place(place)) {
+      auto dst = self->mutable_data<T>(place);
+      std::memcpy(dst, array.data(), array.nbytes());
     } else {
       PADDLE_THROW(platform::errors::InvalidArgument(
           "Incompatible place type: Tensor.set() supports "

python/paddle/fluid/dataloader/dataloader_iter.py

@@ -24,6 +24,7 @@
 import numpy as np
 import multiprocessing
 from collections import namedtuple
+from paddle.fluid.framework import _set_expected_place, _current_expected_place
 
 # NOTE: queue has a different name in python2 and python3
 if six.PY2:
@@ -297,12 +298,20 @@ def _init_thread(self):
             self._need_check_feed, self._places, self._use_buffer_reader, True,
             self._pin_memory)
 
-        self._thread = threading.Thread(target=self._thread_loop)
+        self._thread = threading.Thread(
+            target=self._thread_loop, args=(_current_expected_place(), ))
         self._thread.daemon = True
         self._thread.start()
 
-    def _thread_loop(self):
+    def _thread_loop(self, legacy_expected_place):
         try:
+            #NOTE(zhiqiu): Set the expected place for new thread as the same as father thread,
+            # and it will call platform::SetDeviceId() in c++ internally.
+            # If we do not set cudaDeviceId in new thread, the default cudaDeviceId will be 0,
+            # Which may cost hundreds of MB of GPU memory on CUDAPlace(0) if calling some cuda 
+            # APIs in this thread.
+            _set_expected_place(legacy_expected_place)
+
             for indices in self._sampler_iter:
                 # read data from dataset in mini-batch
                 batch = self._dataset_fetcher.fetch(indices)
@@ -563,7 +572,8 @@ def _init_thread(self):
             self._pin_memory)
 
         self._thread_done_event = threading.Event()
-        self._thread = threading.Thread(target=self._thread_loop)
+        self._thread = threading.Thread(
+            target=self._thread_loop, args=(_current_expected_place(), ))
         self._thread.daemon = True
         self._thread.start()
 
@@ -603,7 +613,14 @@ def _exit_thread_unexpectedly(self):
         self._blocking_queue.kill()
         logging.error("DataLoader reader thread raised an exception!")
 
-    def _thread_loop(self):
+    def _thread_loop(self, legacy_expected_place):
+        #NOTE(zhiqiu): Set the expected place for new thread as the same as father thread,
+        # and it will call platform::SetDeviceId() in c++ internally.
+        # If we do not set cudaDeviceId in new thread, the default cudaDeviceId will be 0,
+        # Which may cost hundreds of MB of GPU memory on CUDAPlace(0) if calling some cuda 
+        # APIs in this thread.
+        _set_expected_place(legacy_expected_place)
+
         while not self._thread_done_event.is_set():
             batch = self._get_data()
             if not self._thread_done_event.is_set():

python/paddle/fluid/dygraph/base.py

@@ -379,7 +379,6 @@ def guard(place=None):
         expected_place = _get_paddle_place(place)
     else:
         expected_place = framework._current_expected_place()
-    tracer._expected_place = expected_place
 
     with framework.program_guard(train, startup):
         with framework.unique_name.guard():

python/paddle/fluid/framework.py

@@ -5661,15 +5661,15 @@ def _get_var(name, program=None):
 @signature_safe_contextmanager
 def _dygraph_guard(tracer):
     global _dygraph_tracer_
-    tmp_trace = _dygraph_tracer_
+    tmp_tracer = _dygraph_tracer_
     _dygraph_tracer_ = tracer
     core._switch_tracer(tracer)
 
     try:
         yield
     finally:
-        core._switch_tracer(tmp_trace)
-        _dygraph_tracer_ = tmp_trace
+        core._switch_tracer(tmp_tracer)
+        _dygraph_tracer_ = tmp_tracer
 
 
 @signature_safe_contextmanager
@@ -5678,10 +5678,13 @@ def _dygraph_place_guard(place):
     tmp_place = _global_expected_place_
     _global_expected_place_ = place
 
+    _set_dygraph_tracer_expected_place(place)
+
     try:
         yield
     finally:
         _global_expected_place_ = tmp_place
+        _set_dygraph_tracer_expected_place(tmp_place)
 
 
 def load_op_library(lib_filename):

python/paddle/fluid/layers/io.py

@@ -32,7 +32,7 @@
 import logging
 from ..data_feeder import check_dtype, check_type
 from paddle.fluid.framework import static_only
-from ..framework import _get_paddle_place
+from ..framework import _get_paddle_place, _current_expected_place, _set_expected_place
 
 __all__ = [
     'data', 'read_file', 'double_buffer', 'py_reader',
@@ -475,8 +475,11 @@ def _py_reader(capacity,
     reader.exited = False
 
     def start_provide_thread(func):
-        def __provider_thread__():
+        def __provider_thread__(legacy_expected_place):
             try:
+                # See _DataLoaderIterSingleProcess._thread_loop() for why set expected place here.
+                _set_expected_place(legacy_expected_place)
+
                 for tensors in func():
                     array = core.LoDTensorArray()
                     for item in tensors:
@@ -498,7 +501,8 @@ def __provider_thread__():
                 logging.warn('Your decorated reader has raised an exception!')
                 six.reraise(*sys.exc_info())
 
-        reader.thread = threading.Thread(target=__provider_thread__)
+        reader.thread = threading.Thread(
+            target=__provider_thread__, args=(_current_expected_place(), ))
         reader.thread.daemon = True
         reader.thread.start()
 

python/paddle/fluid/reader.py

@@ -28,6 +28,7 @@
 from .layers.io import monkey_patch_reader_methods, _copy_reader_var_, double_buffer
 from .unique_name import UniqueNameGenerator
 from .framework import _get_paddle_place, _get_paddle_place_list
+from paddle.fluid.framework import _set_expected_place, _current_expected_place
 import logging
 import warnings
 
@@ -928,12 +929,14 @@ def _start(self):
             # Set reader_thread
             self._thread_done_event = threading.Event()
             self._thread = threading.Thread(
-                target=self._reader_thread_loop_for_multiprocess)
+                target=self._reader_thread_loop_for_multiprocess,
+                args=(_current_expected_place(), ))
             self._thread.daemon = True
             self._thread.start()
         else:
             self._thread = threading.Thread(
-                target=self._reader_thread_loop_for_singleprocess)
+                target=self._reader_thread_loop_for_singleprocess,
+                args=(_current_expected_place(), ))
             self._thread.daemon = True
             self._thread.start()
 
@@ -968,7 +971,10 @@ def _exit_thread_unexpectedly(self):
         self._blocking_queue.kill()
         logging.error("DataLoader reader thread raised an exception!")
 
-    def _reader_thread_loop_for_multiprocess(self):
+    def _reader_thread_loop_for_multiprocess(self, legacy_expected_place):
+        # See _DataLoaderIterSingleProcess._thread_loop() for why set expected place here.
+        _set_expected_place(legacy_expected_place)
+
         while not self._thread_done_event.is_set():
             try:
                 # NOTE: [ avoid hanging ] Even with carefully designed data dependencies 
@@ -1007,8 +1013,11 @@ def _reader_thread_loop_for_multiprocess(self):
                 else:
                     self._exit_thread_expectedly()
 
-    def _reader_thread_loop_for_singleprocess(self):
+    def _reader_thread_loop_for_singleprocess(self, legacy_expected_place):
         try:
+            # See _DataLoaderIterSingleProcess._thread_loop() for why set expected place here.
+            _set_expected_place(legacy_expected_place)
+
             for sample in self._batch_reader():
                 array = core.LoDTensorArray()
                 for item in sample:
@@ -1248,8 +1257,11 @@ def reset(self):
         self._reset()
 
     def _start(self):
-        def __thread_main__():
+        def __thread_main__(legacy_expected_place):
             try:
+                # See _DataLoaderIterSingleProcess._thread_loop() for why set expected place here.
+                _set_expected_place(legacy_expected_place)
+
                 while not self._queue.wait_for_inited(1):
                     if self._exited:
                         return
@@ -1276,7 +1288,8 @@ def __thread_main__():
                 logging.warn('Your reader has raised an exception!')
                 six.reraise(*sys.exc_info())
 
-        self._thread = threading.Thread(target=__thread_main__)
+        self._thread = threading.Thread(
+            target=__thread_main__, args=(_current_expected_place(), ))
         self._thread.daemon = True
         self._thread.start()