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44 
45 #ifndef KOKKOS_SYCL_UNIQUE_TOKEN_HPP
46 #define KOKKOS_SYCL_UNIQUE_TOKEN_HPP
47 
48 #include <impl/Kokkos_ConcurrentBitset.hpp>
49 #include <Kokkos_SYCL_Space.hpp>
50 #include <Kokkos_UniqueToken.hpp>
51 
52 namespace Kokkos {
53 namespace Experimental {
54 
55 // both global and instance Unique Tokens are implemented in the same way
56 template <>
57 class UniqueToken<SYCL, UniqueTokenScope::Global> {
58  protected:
59   uint32_t volatile* m_buffer;
60   uint32_t m_count;
61 
62  public:
63   using execution_space = SYCL;
64   using size_type       = int32_t;
65 
UniqueToken(execution_space const &=execution_space ())66   explicit UniqueToken(execution_space const& = execution_space())
67       : m_buffer(Impl::SYCLInternal::singleton().m_scratchConcurrentBitset),
68         m_count(SYCL::concurrency()) {}
69 
70   KOKKOS_DEFAULTED_FUNCTION
71   UniqueToken(const UniqueToken&) = default;
72 
73   KOKKOS_DEFAULTED_FUNCTION
74   UniqueToken(UniqueToken&&) = default;
75 
76   KOKKOS_DEFAULTED_FUNCTION
77   UniqueToken& operator=(const UniqueToken&) = default;
78 
79   KOKKOS_DEFAULTED_FUNCTION
80   UniqueToken& operator=(UniqueToken&&) = default;
81 
82   /// \brief upper bound for acquired values, i.e. 0 <= value < size()
83   KOKKOS_INLINE_FUNCTION
size() const84   size_type size() const noexcept { return m_count; }
85 
86   /// \brief acquire value such that 0 <= value < size()
87   KOKKOS_INLINE_FUNCTION
acquire() const88   size_type acquire() const {
89     const Kokkos::pair<int, int> result =
90         Kokkos::Impl::concurrent_bitset::acquire_bounded(
91             m_buffer, m_count
92 #if defined(KOKKOS_ARCH_INTEL_GEN)
93             ,
94             Kokkos::Impl::clock_tic() % m_count
95 #endif
96         );
97 
98     if (result.first < 0) {
99       Kokkos::abort(
100           "UniqueToken<SYCL> failure to acquire tokens, no tokens available");
101     }
102 
103     return result.first;
104   }
105 
106   /// \brief release an acquired value
107   KOKKOS_INLINE_FUNCTION
release(size_type i) const108   void release(size_type i) const noexcept {
109     Kokkos::Impl::concurrent_bitset::release(m_buffer, i);
110   }
111 };
112 
113 template <>
114 class UniqueToken<SYCL, UniqueTokenScope::Instance>
115     : public UniqueToken<SYCL, UniqueTokenScope::Global> {
116   View<uint32_t*, SYCLDeviceUSMSpace> m_buffer_view;
117 
118  public:
UniqueToken(execution_space const & arg=execution_space ())119   explicit UniqueToken(execution_space const& arg = execution_space())
120       : UniqueToken<SYCL, UniqueTokenScope::Global>(arg) {}
121 
UniqueToken(size_type max_size,execution_space const &=execution_space ())122   UniqueToken(size_type max_size, execution_space const& = execution_space())
123       : m_buffer_view(
124             "UniqueToken::m_buffer_view",
125             ::Kokkos::Impl::concurrent_bitset::buffer_bound(max_size)) {
126     m_buffer = m_buffer_view.data();
127     m_count  = max_size;
128   }
129 };
130 
131 }  // namespace Experimental
132 }  // namespace Kokkos
133 
134 #endif
135