enable eigen multi-threads on mobile device (#10938)

Author: hjchen2

CMakeLists.txt

@@ -57,6 +57,7 @@ option(GLIDE_INSTALL    "Download and install go dependencies "         ON)
 option(USE_NNPACK       "Compile PaddlePaddle with NNPACK library"      OFF)
 option(WITH_DISTRIBUTE  "Compile with grpc distributed support"         OFF)
 option(USE_EIGEN_FOR_BLAS   "Use matrix multiplication in Eigen"        OFF)
+option(EIGEN_USE_THREADS "Compile with multi-threaded Eigen"            OFF)
 option(WITH_ARM_FP16    "Use half precision support on armv8.2-a cpu"   OFF)
 option(WITH_FAST_BUNDLE_TEST    "Bundle tests that can be run in a single process together to reduce launch overhead"   OFF)
 option(WITH_CONTRIB     "Compile the third-party contributation"        OFF)

cmake/configure.cmake

@@ -41,6 +41,10 @@ if(USE_EIGEN_FOR_BLAS)
     add_definitions(-DPADDLE_USE_EIGEN_FOR_BLAS)
 endif(USE_EIGEN_FOR_BLAS)
 
+if(EIGEN_USE_THREADS)
+    add_definitions(-DEIGEN_USE_THREADS)
+endif(EIGEN_USE_THREADS)
+
 if(NOT WITH_PROFILER)
     add_definitions(-DPADDLE_DISABLE_PROFILER)
 endif(NOT WITH_PROFILER)

paddle/function/EigenGemm.cpp

@@ -13,7 +13,7 @@ See the License for the specific language governing permissions and
 limitations under the License. */
 
 #include <glog/logging.h>
-#include "unsupported/Eigen/CXX11/Tensor"
+#include "paddle/function/EigenThreadDevice.h"
 
 namespace paddle {
 
@@ -70,25 +70,26 @@ struct EigenBlasGemm {
     dims[0].first = transA ? 0 : 1;
     dims[0].second = transB ? 1 : 0;
 
-    Eigen::DefaultDevice device;
+    auto* device = EigenDeviceWarpper::device();
     if (N == ldc) {
       if (alpha == T(1) && beta == T(0)) {
-        c.device(device) = a.contract(b, dims);
+        c.device(*device) = a.contract(b, dims);
       } else if (alpha == T(1) && beta == T(1)) {
-        c.device(device) += a.contract(b, dims);
+        c.device(*device) += a.contract(b, dims);
       } else {
-        c.device(device) = alpha * a.contract(b, dims) + beta * c;
+        c.device(*device) = alpha * a.contract(b, dims) + beta * c;
       }
     } else {
       if (alpha == T(1) && beta == T(0)) {
-        c.slice(offsetC, extentC).device(device) = a.contract(b, dims);
+        c.slice(offsetC, extentC).device(*device) = a.contract(b, dims);
       } else if (alpha == T(1) && beta == T(1)) {
-        c.slice(offsetC, extentC).device(device) += a.contract(b, dims);
+        c.slice(offsetC, extentC).device(*device) += a.contract(b, dims);
       } else {
-        c.slice(offsetC, extentC).device(device) =
+        c.slice(offsetC, extentC).device(*device) =
             alpha * a.contract(b, dims) + beta * c.slice(offsetC, extentC);
       }
     }
+    EigenDeviceWarpper::free_device(device);
   }
 };
 

paddle/function/EigenThreadDevice.h

@@ -0,0 +1,73 @@
+/* Copyright (c) 2016 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. */
+
+#pragma once
+
+#if defined(__OSX__) || defined(__APPLE__)
+#include <sys/sysctl.h>
+#include <sys/types.h>
+#endif
+#include "unsupported/Eigen/CXX11/Tensor"
+
+namespace paddle {
+
+#if defined(__ANDROID__)
+int GetCpuCount() {
+  FILE* fp = fopen("/sys/devices/system/cpu/possible", "r");
+  if (!fp) {
+    return 1;
+  }
+  int rank0, rank1;
+  int num = fscanf(fp, "%d-%d", &rank0, &rank1);
+  fclose(fp);
+  if (num < 2) return 1;
+  return rank1 + 1;
+}
+#elif defined(__OSX__) || defined(__APPLE__)
+int GetCpuCount() {
+  int count = 0;
+  size_t len = sizeof(int);
+  sysctlbyname("hw.ncpu", &count, &len, NULL, 0);
+  return count > 0 ? count : 1;
+}
+#else
+int GetCpuCount() { return 1; }
+#endif
+
+class EigenDeviceWarpper {
+public:  // NOLINT
+#if EIGEN_USE_THREADS
+  static Eigen::ThreadPoolDevice* device() {
+    const int num_cpus = GetCpuCount();
+    const int num_threads = (num_cpus > 2) ? 2 : num_cpus;
+    static Eigen::ThreadPool tp(num_threads);
+    static Eigen::ThreadPoolDevice* device =
+        new Eigen::ThreadPoolDevice(&tp, num_threads);
+    return device;
+  }
+
+  static void free_device(Eigen::ThreadPoolDevice* device) {
+    // do nothing
+  }
+#else
+  static Eigen::DefaultDevice* device() {
+    Eigen::DefaultDevice* device = new Eigen::DefaultDevice;
+    return device;
+  }
+
+  static void free_device(Eigen::DefaultDevice* device) { delete device; }
+#endif
+};
+
+}  // namespace paddle