Buf fix for reset grad inplace version (#37811)

* Debug

* Fixed issue with reset_grad_inplace_version when used with clear_gradient & cross-batch accumulation

* Rearranged interfaces

* Fixed ci issues

paddle/fluid/framework/tensor.h

@@ -81,6 +81,7 @@ class TensorInplaceVersion {
   bool IsUnique() const { return inplace_version_ == 0; }
   void Bump() { ++inplace_version_; }
   uint32_t CurrentVersion() const { return inplace_version_; }
+  void SetInplaceVersionToZero() { inplace_version_ = 0; }
 
  private:
   uint32_t inplace_version_;

paddle/fluid/framework/variable.h

@@ -75,6 +75,7 @@ class Variable {
   framework::TensorInplaceVersion* InplaceVersionCounter();
 
  public:
+  void SetInplaceVersionToZero();
   uint32_t CurrentInplaceVersion();
   void BumpInplaceVersion();
 
@@ -134,6 +135,12 @@ inline framework::TensorInplaceVersion* Variable::InplaceVersionCounter() {
   return version_counter_ptr;
 }
 
+inline void Variable::SetInplaceVersionToZero() {
+  auto inplace_version_counter = this->InplaceVersionCounter();
+  if (inplace_version_counter)
+    inplace_version_counter->SetInplaceVersionToZero();
+}
+
 inline uint32_t Variable::CurrentInplaceVersion() {
   auto version_counter_ptr = InplaceVersionCounter();
   if (version_counter_ptr) {

paddle/fluid/imperative/variable_wrapper.h

@@ -209,13 +209,23 @@ class VariableWrapper {
 
   uint32_t InplaceVersionSnapshot() const { return inplace_version_snapshot_; }
 
-  void ResetInplaceVersion() {
+  void ResetInplaceVersion(bool set_to_zero = false) {
+    if (!set_to_zero) {
       auto new_version = var_.CurrentInplaceVersion();
 
       VLOG(6) << "The wrapper version of VariableWrapper '" << name_
               << "' will be updated from " << inplace_version_snapshot_ << "to "
               << new_version;
       inplace_version_snapshot_ = new_version;
+
+    } else {
+      // Reset Snapshot & InplaceVersion to zero
+      inplace_version_snapshot_ = 0;
+      auto var = this->MutableVar();
+      if (var) {
+        var->SetInplaceVersionToZero();
+      }
+    }
   }
 
   bool hasCacheKey(const paddle::framework::OpKernelType& key) {

paddle/fluid/pybind/imperative.cc

@@ -1538,7 +1538,7 @@ void BindImperative(py::module *m_ptr) {
              self.MutableGradVarBase()->SetType(type);
            })
       .def("_reset_grad_inplace_version",
-           [](imperative::VarBase &self) {
+           [](imperative::VarBase &self, bool set_to_zero) {
              /*
              *** This interfaceis a complete hack ***
              reset_grad_inplace_version removes all inplace related records to
@@ -1550,15 +1550,20 @@ void BindImperative(py::module *m_ptr) {
              Make sure you fully understand what you're doing before make use of
              this interface, and prepare for the worst.
              */
+             py::gil_scoped_release release;
+
              if (self.HasGradVar()) {
                auto grad_var = self.GradVarBase();
                auto var_wrapper = grad_var->SharedVar();
-               if (var_wrapper) var_wrapper->ResetInplaceVersion();
+               if (var_wrapper) {
+                 var_wrapper->ResetInplaceVersion(set_to_zero);
+               }
              }
            })
       .def("_grad_ivar",
            [](const imperative::VarBase &self) {
              auto &grad_var = self.GradVarBase();
+
              if (grad_var && grad_var->Var().IsInitialized()) {
                auto *tensor =
                    grad_var->MutableVar()->IsType<framework::LoDTensor>()
@@ -1567,6 +1572,7 @@ void BindImperative(py::module *m_ptr) {
                        : grad_var->MutableVar()
                              ->GetMutable<framework::SelectedRows>()
                              ->mutable_value();
+
                if (tensor->IsInitialized()) {
                  return grad_var;
                }

python/paddle/distributed/fleet/meta_parallel/sharding/sharding_stage2.py

@@ -177,7 +177,7 @@ class ShardingStage2(nn.Layer):
         for param in self._trainable_params:
             if param.name in self._param_grads and param.grad is not None:
                 param.grad.scale_(scale=self._world_size_scaling)
-                param._reset_grad_inplace_version()
+                param._reset_grad_inplace_version(True)
 
     def _init_internal_storage(self, needs_fresh):
         """
@@ -283,7 +283,7 @@ class ShardingStage2(nn.Layer):
                     self._grad_reduced[index] = False
                     if not self._accumulate_grads:
                         param.grad.scale_(scale=self._world_size_scaling)
-                    param._reset_grad_inplace_version()
+                    param._reset_grad_inplace_version(True)
 
                     # Clear the gradient that does not belong to the current rank through the callback function
                     def cleanup():

python/paddle/fluid/tests/unittests/test_reset_grad_inplace_version.py

@@ -20,12 +20,13 @@ import unittest
 paddle.set_device('cpu')
 
 
-def clear_grad(w, a):
+# Test 1
+def clear_grad_test_0(w, a):
     @paddle.no_grad()
     def warp(*_):
         assert w.grad is not None
         _C_ops.scale_(w.grad, 'scale', 0.5)
-        w._reset_grad_inplace_version()
+        w._reset_grad_inplace_version(True)
 
     return warp
 
@@ -35,7 +36,7 @@ class TestInplaceAndClearGradient(unittest.TestCase):
         input_data = np.ones([1, 1])
         w = paddle.to_tensor(input_data, 'float32', stop_gradient=False)
 
-        _clear_grad = clear_grad(w, a="1")
+        _clear_grad = clear_grad_test_0(w, a="1")
         w._register_backward_hook(_clear_grad)
         for i in range(2):
             print(" Step: ", i)
@@ -45,5 +46,60 @@ class TestInplaceAndClearGradient(unittest.TestCase):
         assert w.grad[0] == 0.15
 
 
+# Test 2
+class Counter:
+    def __init__(self):
+        self.num_calls = 0
+        self.step = 0
+
+
+def clear_grad_test_1(w, c):
+    @paddle.no_grad()
+    def warp(*_):
+        assert w.grad is not None
+        if c.step == 1:
+            w.grad.scale_(scale=0.5)
+            w._reset_grad_inplace_version(True)
+
+        c.num_calls += 1
+
+    return warp
+
+
+class TestInplaceClearGradAccumulation(unittest.TestCase):
+    def test(self):
+        input_data = np.ones([1, 1])
+        w = paddle.to_tensor(input_data, 'float32', stop_gradient=False)
+        c = Counter()
+
+        _clear_grad = clear_grad_test_1(w, c)
+        w._register_backward_hook(_clear_grad)
+
+        for c.step in range(5):
+            out0 = _C_ops.scale(w, 'scale', 0.1)
+            out = _C_ops.matmul_v2(out0, w, 'trans_x', False, 'trans_y', False)
+
+            out.backward()
+
+            if c.step == 1:
+                w.clear_gradient(False)
+
+            assert c.num_calls == 1
+            c.num_calls = 0
+
+
+class TestInplaceClearGradAccumulationAlt(unittest.TestCase):
+    def test(self):
+        input_data = np.ones([1, 1])
+        w = paddle.to_tensor(input_data, 'float32', stop_gradient=False)
+        out = _C_ops.scale(w, 'scale', 0.1)
+        out.backward()
+
+        w.grad.scale_(scale=0.5)
+        w._reset_grad_inplace_version(False)
+
+        assert w.grad._inplace_version() == 1
+
+
 if __name__ == '__main__':
     unittest.main()