From 46d2faf217ae2164884681d5444bd7b05520852e Mon Sep 17 00:00:00 2001
From: Yuuichi Asahi <y.asahi@nr.titech.ac.jp>
Date: Mon, 6 Jan 2025 14:35:27 +0900
Subject: [PATCH] call fftw_cleanup_threads only once

---
 fft/src/KokkosFFT_FFTW_Types.hpp | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/fft/src/KokkosFFT_FFTW_Types.hpp b/fft/src/KokkosFFT_FFTW_Types.hpp
index c605f51f..7e739d66 100644
--- a/fft/src/KokkosFFT_FFTW_Types.hpp
+++ b/fft/src/KokkosFFT_FFTW_Types.hpp
@@ -5,6 +5,7 @@
 #ifndef KOKKOSFFT_FFTW_TYPES_HPP
 #define KOKKOSFFT_FFTW_TYPES_HPP
 
+#include <mutex>
 #include <fftw3.h>
 #include <Kokkos_Core.hpp>
 #include "KokkosFFT_common_types.hpp"
@@ -68,13 +69,15 @@ struct ScopedFFTWPlan {
       std::conditional_t<std::is_same_v<floating_point_type, float>, fftwf_plan,
                          fftw_plan>;
   plan_type m_plan;
+  const int m_local_id;
 
  public:
   template <typename InScalarType, typename OutScalarType>
   ScopedFFTWPlan(const ExecutionSpace &exec_space, int rank, const int *n,
                  int howmany, InScalarType *in, const int *inembed, int istride,
                  int idist, OutScalarType *out, const int *onembed, int ostride,
-                 int odist, [[maybe_unused]] int sign, unsigned flags) {
+                 int odist, [[maybe_unused]] int sign, unsigned flags)
+      : m_local_id(global_id()) {
     init_threads(exec_space);
     constexpr auto type = fftw_transform_type<T1, T2>::type();
     if constexpr (type == KokkosFFT::Impl::FFTWTransformType::R2C) {
@@ -121,6 +124,13 @@ struct ScopedFFTWPlan {
   plan_type plan() const noexcept { return m_plan; }
 
  private:
+  static int global_id() {
+    static int global_id = 0;
+    static std::mutex mtx;
+    std::lock_guard<std::mutex> lock(mtx);
+    return global_id++;
+  }
+
   static void init_threads([[maybe_unused]] const ExecutionSpace &exec_space) {
 #if defined(KOKKOS_ENABLE_OPENMP) || defined(KOKKOS_ENABLE_THREADS)
     if constexpr (std::is_same_v<ExecutionSpace,
@@ -128,10 +138,10 @@ struct ScopedFFTWPlan {
       int nthreads = exec_space.concurrency();
 
       if constexpr (std::is_same_v<plan_type, fftwf_plan>) {
-        fftwf_init_threads();
+        if (m_local_id == 0) fftwf_init_threads();
         fftwf_plan_with_nthreads(nthreads);
       } else {
-        fftw_init_threads();
+        if (m_local_id == 0) fftw_init_threads();
         fftw_plan_with_nthreads(nthreads);
       }
     }
@@ -143,9 +153,9 @@ struct ScopedFFTWPlan {
     if constexpr (std::is_same_v<ExecutionSpace,
                                  Kokkos::DefaultHostExecutionSpace>) {
       if constexpr (std::is_same_v<plan_type, fftwf_plan>) {
-        fftwf_cleanup_threads();
+        if (m_local_id == 0) fftwf_cleanup_threads();
       } else {
-        fftw_cleanup_threads();
+        if (m_local_id == 0) fftw_cleanup_threads();
       }
     }
 #endif