Remove tags from core interface

docs/api/core.rst

@@ -6,7 +6,7 @@ Point-to-point
 
 .. cpp:namespace:: KokkosComm
 
-.. cpp:function:: template <KokkosView SendView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace, Transport TRANSPORT = DefaultTransport> Req<TRANSPORT> send(Handle<ExecSpace, TRANSPORT> &h, SendView &sv, int dest, int tag)
+.. cpp:function:: template <KokkosView SendView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace, Transport TRANSPORT = DefaultTransport> Req<TRANSPORT> send(Handle<ExecSpace, TRANSPORT> &h, SendView &sv, int dest)
 
   Initiates a non-blocking send operation.
 
@@ -20,11 +20,10 @@ Point-to-point
   :param h: A handle to the execution space and transport mechanism.
   :param sv: The Kokkos view to send.
   :param dest: The destination rank.
-  :param tag: The message tag.
 
   :return: A request object for the non-blocking send operation.
 
-.. cpp:function:: template <KokkosView SendView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace, Transport TRANSPORT = DefaultTransport> Req<TRANSPORT> send(SendView &sv, int dest, int tag)
+.. cpp:function:: template <KokkosView SendView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace, Transport TRANSPORT = DefaultTransport> Req<TRANSPORT> send(SendView &sv, int dest)
 
    Initiates a non-blocking send operation using a default handle.
 
@@ -37,7 +36,6 @@ Point-to-point
 
    :param sv: The Kokkos view to send.
    :param dest: The destination rank.
-   :param tag: The message tag.
 
    :return: A request object for the non-blocking send operation.
 
@@ -48,7 +46,7 @@ Point-to-point
 
 
 
-.. cpp:function:: template <KokkosView RecvView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace, Transport TRANSPORT = DefaultTransport> Req<TRANSPORT> recv(Handle<ExecSpace, TRANSPORT> &h, RecvView &rv, int src, int tag)
+.. cpp:function:: template <KokkosView RecvView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace, Transport TRANSPORT = DefaultTransport> Req<TRANSPORT> recv(Handle<ExecSpace, TRANSPORT> &h, RecvView &rv, int src)
 
    Initiates a non-blocking receive operation.
 
@@ -62,7 +60,6 @@ Point-to-point
    :param h: A handle to the execution space and transport mechanism.
    :param rv: The Kokkos view where the received data will be stored.
    :param src: The source rank from which to receive data.
-   :param tag: The message tag to identify the communication.
 
    :return: A request object of type `Req<TRANSPORT>` representing the non-blocking receive operation.
 
@@ -77,7 +74,7 @@ Point-to-point
 
 
 
-.. cpp:function:: template <KokkosView RecvView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace, Transport TRANSPORT = DefaultTransport> Req<TRANSPORT> recv(RecvView &rv, int src, int tag)
+.. cpp:function:: template <KokkosView RecvView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace, Transport TRANSPORT = DefaultTransport> Req<TRANSPORT> recv(RecvView &rv, int src)
 
    Initiates a non-blocking receive operation using a default handle.
 
@@ -90,7 +87,6 @@ Point-to-point
 
    :param rv: The Kokkos view where the received data will be stored.
    :param src: The source rank from which to receive data.
-   :param tag: The message tag to identify the communication.
 
    :return: A request object of type `Req<TRANSPORT>` representing the non-blocking receive operation.
 

docs/api/core_recv.cpp

@@ -1,4 +1,4 @@
 Handle<> handle;
 Kokkos::View<double*> recv_view("recv_view", 100);
-auto req = recv(handle, recv_view, 1/*src*/, 0/*tag*/);
+auto req = recv(handle, recv_view, 1/*src*/);
 KokkosComm::wait(req);

docs/api/core_send.cpp

@@ -14,16 +14,15 @@ Kokkos::parallel_for("fill_data", Kokkos::RangePolicy<ExecSpace>(0, 100), KOKKOS
 
 // Destination rank and message tag
 int dest = 1;
-int tag = 42;
 
 // Create a handle
 KokkosComm::Handle<> handle; // Same as Handle<Execspace, Transport>
 
 // Initiate a non-blocking send with a handle
-auto req1 = send(handle, data, dest, tag);
+auto req1 = send(handle, data, dest);
 
 // Initiate a non-blocking send with a default handle
-auto req2 = send(data, dest, tag);
+auto req2 = send(data, dest);
 
 // Wait for the requests to complete (assuming a wait function exists)
 KokkosComm::wait(req1);

perf_tests/test_2dhalo.cpp

@@ -50,15 +50,15 @@ void send_recv(benchmark::State &, MPI_Comm comm, const Space &space, int nx, in
 
   std::vector<KokkosComm::Req<>> reqs;
   // std::cerr << get_rank(rx, ry) << " -> " << get_rank(xp1, ry) << "\n";
-  reqs.push_back(KokkosComm::send(h, xp1_s, get_rank(xp1, ry), 0));
-  reqs.push_back(KokkosComm::send(h, xm1_s, get_rank(xm1, ry), 1));
-  reqs.push_back(KokkosComm::send(h, yp1_s, get_rank(rx, yp1), 2));
-  reqs.push_back(KokkosComm::send(h, ym1_s, get_rank(rx, ym1), 3));
-
-  reqs.push_back(KokkosComm::recv(h, xm1_r, get_rank(xm1, ry), 0));
-  reqs.push_back(KokkosComm::recv(h, xp1_r, get_rank(xp1, ry), 1));
-  reqs.push_back(KokkosComm::recv(h, ym1_r, get_rank(rx, ym1), 2));
-  reqs.push_back(KokkosComm::recv(h, yp1_r, get_rank(rx, yp1), 3));
+  reqs.push_back(KokkosComm::send(h, xp1_s, get_rank(xp1, ry)));
+  reqs.push_back(KokkosComm::send(h, xm1_s, get_rank(xm1, ry)));
+  reqs.push_back(KokkosComm::send(h, yp1_s, get_rank(rx, yp1)));
+  reqs.push_back(KokkosComm::send(h, ym1_s, get_rank(rx, ym1)));
+
+  reqs.push_back(KokkosComm::recv(h, xm1_r, get_rank(xm1, ry)));
+  reqs.push_back(KokkosComm::recv(h, xp1_r, get_rank(xp1, ry)));
+  reqs.push_back(KokkosComm::recv(h, ym1_r, get_rank(rx, ym1)));
+  reqs.push_back(KokkosComm::recv(h, yp1_r, get_rank(rx, yp1)));
 
   // wait for comm
   KokkosComm::wait_all(reqs);

perf_tests/test_osu_latency.cpp

@@ -24,9 +24,9 @@
 template <typename Space, typename View>
 void osu_latency_Kokkos_Comm_sendrecv(benchmark::State &, MPI_Comm, KokkosComm::Handle<> &h, const View &v) {
   if (h.rank() == 0) {
-    KokkosComm::wait(KokkosComm::send(h, v, 1, 1));
+    KokkosComm::wait(KokkosComm::send(h, v, 1));
   } else if (h.rank() == 1) {
-    KokkosComm::wait(KokkosComm::recv(h, v, 0, 1));
+    KokkosComm::wait(KokkosComm::recv(h, v, 0));
   }
 }
 

src/KokkosComm_point_to_point.hpp

@@ -25,26 +25,26 @@ namespace KokkosComm {
 
 template <KokkosView RecvView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace,
           CommunicationSpace CommSpace = DefaultCommunicationSpace>
-Req<CommSpace> recv(Handle<ExecSpace, CommSpace> &h, RecvView &rv, int src, int tag) {
-  return Impl::Recv<RecvView, ExecSpace, CommSpace>::execute(h, rv, src, tag);
+Req<CommSpace> recv(Handle<ExecSpace, CommSpace> &h, RecvView &rv, int src) {
+  return Impl::Recv<RecvView, ExecSpace, CommSpace>::execute(h, rv, src);
 }
 
 template <KokkosView RecvView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace,
           CommunicationSpace CommSpace = DefaultCommunicationSpace>
-Req<CommSpace> recv(RecvView &rv, int src, int tag) {
-  return recv<RecvView, ExecSpace, CommSpace>(Handle<ExecSpace, CommSpace>{}, rv, src, tag);
+Req<CommSpace> recv(RecvView &rv, int src) {
+  return recv<RecvView, ExecSpace, CommSpace>(Handle<ExecSpace, CommSpace>{}, rv, src);
 }
 
 template <KokkosView SendView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace,
           CommunicationSpace CommSpace = DefaultCommunicationSpace>
-Req<CommSpace> send(Handle<ExecSpace, CommSpace> &h, SendView &sv, int dest, int tag) {
-  return Impl::Send<SendView, ExecSpace, CommSpace>::execute(h, sv, dest, tag);
+Req<CommSpace> send(Handle<ExecSpace, CommSpace> &h, SendView &sv, int dest) {
+  return Impl::Send<SendView, ExecSpace, CommSpace>::execute(h, sv, dest);
 }
 
 template <KokkosView SendView, KokkosExecutionSpace ExecSpace = Kokkos::DefaultExecutionSpace,
           CommunicationSpace CommSpace = DefaultCommunicationSpace>
-Req<CommSpace> send(SendView &sv, int dest, int tag) {
-  return send<SendView, ExecSpace, CommSpace>(Handle<ExecSpace, CommSpace>{}, sv, dest, tag);
+Req<CommSpace> send(SendView &sv, int dest) {
+  return send<SendView, ExecSpace, CommSpace>(Handle<ExecSpace, CommSpace>{}, sv, dest);
 }
 
 }  // namespace KokkosComm

src/mpi/KokkosComm_mpi_irecv.hpp

@@ -17,14 +17,15 @@
 #pragma once
 
 #include "KokkosComm_mpi.hpp"
+#include "impl/KokkosComm_tags.hpp"
 
 namespace KokkosComm {
 
 namespace Impl {
 // Recv implementation for Mpi
 template <KokkosExecutionSpace ExecSpace, KokkosView RecvView>
 struct Recv<RecvView, ExecSpace, Mpi> {
-  static Req<Mpi> execute(Handle<ExecSpace, Mpi> &h, const RecvView &rv, int src, int tag) {
+  static Req<Mpi> execute(Handle<ExecSpace, Mpi> &h, const RecvView &rv, int src) {
     using KCT    = KokkosComm::Traits<RecvView>;
     using KCPT   = KokkosComm::PackTraits<RecvView>;
     using Packer = typename KCPT::packer_type;
@@ -35,13 +36,13 @@ struct Recv<RecvView, ExecSpace, Mpi> {
     Req<Mpi> req;
     if (KokkosComm::is_contiguous(rv)) {
       space.fence("fence before irecv");
-      MPI_Irecv(KokkosComm::data_handle(rv), 1, view_mpi_type(rv), src, tag, h.mpi_comm(),
+      MPI_Irecv(KokkosComm::data_handle(rv), 1, view_mpi_type(rv), src, POINTTOPOINT_TAG, h.mpi_comm(),
                 &req.mpi_request());  // TODO: probably best to just use the scalar type
       req.extend_view_lifetime(rv);
     } else {
       Args args = Packer::allocate_packed_for(space, "TODO", rv);
       space.fence("fence before irecv");
-      MPI_Irecv(args.view.data(), args.count, args.datatype, src, tag, h.mpi_comm(), &req.mpi_request());
+      MPI_Irecv(args.view.data(), args.count, args.datatype, src, POINTTOPOINT_TAG, h.mpi_comm(), &req.mpi_request());
       req.extend_view_lifetime(rv);
       // implicitly extends args.view lifetime since lambda holds a copy
       req.call_after_mpi_wait([=]() { Packer::unpack_into(space, rv, args.view); });

src/mpi/KokkosComm_mpi_isend.hpp

@@ -20,6 +20,7 @@
 
 #include "KokkosComm_mpi.hpp"
 #include "impl/KokkosComm_types.hpp"
+#include "impl/KokkosComm_tags.hpp"
 #include "KokkosComm_mpi_commmode.hpp"
 
 namespace KokkosComm {
@@ -62,8 +63,8 @@ Req<Mpi> isend_impl(Handle<ExecSpace, Mpi> &h, const SendView &sv, int dest, int
 // Implementation of KokkosComm::Send
 template <KokkosExecutionSpace ExecSpace, KokkosView SendView>
 struct Send<SendView, ExecSpace, Mpi> {
-  static Req<Mpi> execute(Handle<ExecSpace, Mpi> &h, const SendView &sv, int dest, int tag) {
-    return isend_impl<ExecSpace, SendView>(h, sv, dest, tag, mpi::DefaultCommMode{});
+  static Req<Mpi> execute(Handle<ExecSpace, Mpi> &h, const SendView &sv, int dest) {
+    return isend_impl<ExecSpace, SendView>(h, sv, dest, POINTTOPOINT_TAG, mpi::DefaultCommMode{});
   }
 };
 

src/mpi/impl/KokkosComm_tags.hpp

@@ -0,0 +1,5 @@
+#pragma once
+
+namespace KokkosComm::Impl {
+constexpr int POINTTOPOINT_TAG = 17;
+}

unit_tests/test_sendrecv.cpp

@@ -46,10 +46,10 @@ void test_1d(const View1D &a) {
     int dst = 1;
     Kokkos::parallel_for(
         a.extent(0), KOKKOS_LAMBDA(const int i) { a(i) = i; });
-    KokkosComm::wait(KokkosComm::send(h, a, dst, 0));
+    KokkosComm::wait(KokkosComm::send(h, a, dst));
   } else if (1 == h.rank()) {
     int src = 0;
-    KokkosComm::wait(KokkosComm::recv(h, a, src, 0));
+    KokkosComm::wait(KokkosComm::recv(h, a, src));
     int errs;
     Kokkos::parallel_reduce(
         a.extent(0), KOKKOS_LAMBDA(const int &i, int &lsum) { lsum += a(i) != Scalar(i); }, errs);
@@ -74,10 +74,10 @@ void test_2d(const View2D &a) {
     int dst = 1;
     Kokkos::parallel_for(
         policy, KOKKOS_LAMBDA(int i, int j) { a(i, j) = i * a.extent(0) + j; });
-    KokkosComm::wait(KokkosComm::send(h, a, dst, 0));
+    KokkosComm::wait(KokkosComm::send(h, a, dst));
   } else if (1 == h.rank()) {
     int src = 0;
-    KokkosComm::wait(KokkosComm::recv(h, a, src, 0));
+    KokkosComm::wait(KokkosComm::recv(h, a, src));
     int errs;
     Kokkos::parallel_reduce(
         policy, KOKKOS_LAMBDA(int i, int j, int &lsum) { lsum += a(i, j) != Scalar(i * a.extent(0) + j); }, errs);