fix workspace limit in cudnn-8

Author: zhiqiu

paddle/fluid/operators/conv_cudnn_helper.h

@@ -19,6 +19,7 @@ limitations under the License. */
 #include <memory>
 #include <string>
 #include <vector>
+
 #include "paddle/fluid/framework/conv_search_cache.h"
 #include "paddle/fluid/framework/operator_kernel_configs.h"
 #include "paddle/fluid/operators/conv_cudnn_op_cache.h"
@@ -101,6 +102,24 @@ inline int MaxBwdFilterAlgos(cudnnHandle_t cudnn_handle) {
   return max_algos;
 }
 
+template <typename PerfType, typename AlgoType>
+void ChooseAlgoByWorkspace(PerfType* perf_results, size_t perf_num,
+                           size_t workspace_byte, AlgoType* algo) {
+  for (size_t i = 0; i < perf_num; ++i) {
+    auto result = perf_results[i];
+    if (result.status == CUDNN_STATUS_SUCCESS &&
+        result.memory < workspace_byte) {
+      *algo = result.algo;
+      VLOG(3) << "    algo: " << result.algo << ", time: " << result.time
+              << " ms, wksp = " << result.memory
+              << ", status = " << result.status;
+      return;
+    }
+  }
+  VLOG(3) << "Can not find alog that requires memory < "
+          << static_cast<double>(workspace_byte) / (1 << 20) << " MB";
+}
+
 template <typename PerfType, typename AlgoType>
 void ChooseAlgo(const std::vector<PerfType>& perf_results,
                 size_t workspace_byte, AlgoType* algo) {
@@ -219,7 +238,10 @@ struct SearchAlgorithm<cudnnConvolutionFwdAlgoPerf_t> {
 
       if (workspace_size > workspace_size_limit) {
 #if CUDNN_VERSION >= 8000
-        workspace_size_limit = workspace_size;
+        // cudnnGetConvolutionForwardAlgorithm is removed in CUDNN-8
+        ChooseAlgoByWorkspace<perf_t, algo_t>(perf_results.get(),
+                                              kNUM_CUDNN_FWD_ALGS,
+                                              workspace_size_limit, &algo);
 #else
         VLOG(1) << "Fallback to non-v7 method to find conv algorithm becasue "
                    "the workspace size request("
@@ -316,7 +338,6 @@ struct SearchAlgorithm<cudnnConvolutionBwdDataAlgoPerf_t> {
     size_t workspace_size = 0;
     bool has_got_workspace_size = true;
     algo_t algo;
-
 #if CUDA_VERSION >= 9000 && CUDNN_VERSION_MIN(7, 0, 1)
     auto& dev_ctx = ctx.template device_context<platform::CUDADeviceContext>();
     if (dev_ctx.GetComputeCapability() >= 70 && dtype == CUDNN_DATA_HALF) {
@@ -362,9 +383,10 @@ struct SearchAlgorithm<cudnnConvolutionBwdDataAlgoPerf_t> {
       if (workspace_size > workspace_size_limit) {
         has_got_workspace_size = false;
 #if CUDNN_VERSION >= 8000
-        // There is no cudnnGetConvolutionBackwardDataAlgorithm in CUDNN 8
-        // version.
-        workspace_size_limit = workspace_size;
+        // cudnnGetConvolutionBackwardDataAlgorithm is removed in CUDNN-8
+        ChooseAlgoByWorkspace<perf_t, algo_t>(perf_results.get(),
+                                              kNUM_CUDNN_BWD_DATA_ALGS,
+                                              workspace_size_limit, &algo);
 #else
         VLOG(1) << "Fallback to non-v7 method to find conv algorithm becasue "
                    "the workspace size request("
@@ -493,6 +515,23 @@ struct SearchAlgorithm<cudnnConvolutionBwdFilterAlgoPerf_t> {
       workspace_size = GetWorkspaceSize(args, algo);
       if (workspace_size > workspace_size_limit) {
         workspace_size = workspace_size_limit;
+#if CUDNN_VERSION >= 8000
+        // cudnnGetConvolutionBackwardFilterAlgorithm is removed in CUDNN-8
+        ChooseAlgoByWorkspace<perf_t, algo_t>(perf_results.get(),
+                                              kNUM_CUDNN_BWD_FILTER_ALGS,
+                                              workspace_size_limit, &algo);
+#else
+        VLOG(1) << "Fallback to non-v7 method to find conv algorithm becasue "
+                   "the workspace size request("
+                << workspace_size << ") exceeds the limit("
+                << workspace_size_limit << ")";
+        PADDLE_ENFORCE_CUDA_SUCCESS(
+            platform::dynload::cudnnGetConvolutionBackwardFilterAlgorithm(
+                args.handle, args.idesc.desc(), args.odesc.desc(),
+                args.cdesc.desc(), args.wdesc.desc(),
+                CUDNN_CONVOLUTION_BWD_FILTER_SPECIFY_WORKSPACE_LIMIT,
+                workspace_size_limit, &algo));
+#endif
       }
 #else
       PADDLE_ENFORCE_CUDA_SUCCESS(