X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/8a9af89e44c0f7f2f648d402e89a26799910ee31..40616078da72e823931c1fb884949054699ec39d:/src/smpi/colls/allreduce/allreduce-smp-binomial-pipeline.cpp

diff --git a/src/smpi/colls/allreduce/allreduce-smp-binomial-pipeline.cpp b/src/smpi/colls/allreduce/allreduce-smp-binomial-pipeline.cpp
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+++ b/src/smpi/colls/allreduce/allreduce-smp-binomial-pipeline.cpp
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+/* Copyright (c) 2013-2014. The SimGrid Team.
+ * All rights reserved.                                                     */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include "../colls_private.h"
+/* IMPLEMENTED BY PITCH PATARASUK 
+   Non-topoloty-specific (however, number of cores/node need to be changed) 
+   all-reduce operation designed for smp clusters
+   It uses 2-layer communication: binomial for both intra-communication 
+   inter-communication
+   The communication are done in a pipeline fashion */
+
+
+
+/* this is a default segment size for pipelining, 
+   but it is typically passed as a command line argument */
+int allreduce_smp_binomial_pipeline_segment_size = 4096;
+
+/* ** NOTE **
+   This code is modified from allreduce-smp-binomial.c by wrapping the code with pipeline effect as follow
+   for (loop over pipelength) {
+     smp-binomial main code;
+   }
+*/
+
+/* ** NOTE **
+   Use -DMPICH2 if this code does not compile.
+   MPICH1 code also work on MPICH2 on our cluster and the performance are similar.
+   This code assume commutative and associative reduce operator (MPI_SUM, MPI_MAX, etc).
+*/
+
+/*
+This fucntion performs all-reduce operation as follow. ** in a pipeline fashion **
+1) binomial_tree reduce inside each SMP node
+2) binomial_tree reduce intra-communication between root of each SMP node
+3) binomial_tree bcast intra-communication between root of each SMP node
+4) binomial_tree bcast inside each SMP node
+*/
+int smpi_coll_tuned_allreduce_smp_binomial_pipeline(void *send_buf,
+                                                    void *recv_buf, int count,
+                                                    MPI_Datatype dtype,
+                                                    MPI_Op op, MPI_Comm comm)
+{
+  int comm_size, rank;
+  void *tmp_buf;
+  int tag = COLL_TAG_ALLREDUCE;
+  int mask, src, dst;
+  MPI_Status status;
+  if(comm->get_leaders_comm()==MPI_COMM_NULL){
+    comm->init_smp();
+  }
+  int num_core=1;
+  if (comm->is_uniform()){
+    num_core = comm->get_intra_comm()->size();
+  }
+
+  comm_size = comm->size();
+  rank = comm->rank();
+  MPI_Aint extent;
+  extent = dtype->get_extent();
+  tmp_buf = (void *) smpi_get_tmp_sendbuffer(count * extent);
+
+  int intra_rank, inter_rank;
+  intra_rank = rank % num_core;
+  inter_rank = rank / num_core;
+
+  int phase;
+  int send_offset;
+  int recv_offset;
+  int pcount = allreduce_smp_binomial_pipeline_segment_size;
+  if (pcount > count) {
+    pcount = count;
+  }
+
+  /* size of processes participate in intra communications =>
+     should be equal to number of machines */
+  int inter_comm_size = (comm_size + num_core - 1) / num_core;
+
+  /* copy input buffer to output buffer */
+  Request::sendrecv(send_buf, count, dtype, rank, tag,
+               recv_buf, count, dtype, rank, tag, comm, &status);
+
+  /* compute pipe length */
+  int pipelength;
+  pipelength = count / pcount;
+
+  /* pipelining over pipelength (+3 is because we have 4 stages:
+     reduce-intra, reduce-inter, bcast-inter, bcast-intra */
+  for (phase = 0; phase < pipelength + 3; phase++) {
+
+    /* start binomial reduce intra communication inside each SMP node */
+    if (phase < pipelength) {
+      mask = 1;
+      while (mask < num_core) {
+        if ((mask & intra_rank) == 0) {
+          src = (inter_rank * num_core) + (intra_rank | mask);
+          if (src < comm_size) {
+            recv_offset = phase * pcount * extent;
+            Request::recv(tmp_buf, pcount, dtype, src, tag, comm, &status);
+            if(op!=MPI_OP_NULL) op->apply( tmp_buf, (char *)recv_buf + recv_offset, &pcount, dtype);
+          }
+        } else {
+          send_offset = phase * pcount * extent;
+          dst = (inter_rank * num_core) + (intra_rank & (~mask));
+          Request::send((char *)recv_buf + send_offset, pcount, dtype, dst, tag, comm);
+          break;
+        }
+        mask <<= 1;
+      }
+    }
+
+    /* start binomial reduce inter-communication between each SMP nodes: 
+       each node only have one process that can communicate to other nodes */
+    if ((phase > 0) && (phase < (pipelength + 1))) {
+      if (intra_rank == 0) {
+
+        mask = 1;
+        while (mask < inter_comm_size) {
+          if ((mask & inter_rank) == 0) {
+            src = (inter_rank | mask) * num_core;
+            if (src < comm_size) {
+              recv_offset = (phase - 1) * pcount * extent;
+              Request::recv(tmp_buf, pcount, dtype, src, tag, comm, &status);
+              if(op!=MPI_OP_NULL) op->apply( tmp_buf, (char *)recv_buf + recv_offset, &pcount, dtype);
+            }
+          } else {
+            dst = (inter_rank & (~mask)) * num_core;
+            send_offset = (phase - 1) * pcount * extent;
+            Request::send((char *)recv_buf + send_offset, pcount, dtype, dst, tag, comm);
+            break;
+          }
+          mask <<= 1;
+        }
+      }
+    }
+
+    /* start binomial broadcast inter-communication between each SMP nodes: 
+       each node only have one process that can communicate to other nodes */
+    if ((phase > 1) && (phase < (pipelength + 2))) {
+      if (intra_rank == 0) {
+        mask = 1;
+        while (mask < inter_comm_size) {
+          if (inter_rank & mask) {
+            src = (inter_rank - mask) * num_core;
+            recv_offset = (phase - 2) * pcount * extent;
+            Request::recv((char *)recv_buf + recv_offset, pcount, dtype, src, tag, comm,
+                     &status);
+            break;
+          }
+          mask <<= 1;
+        }
+        mask >>= 1;
+
+        while (mask > 0) {
+          if (inter_rank < inter_comm_size) {
+            dst = (inter_rank + mask) * num_core;
+            if (dst < comm_size) {
+              //printf("Node %d send to node %d when mask is %d\n", rank, dst, mask);
+              send_offset = (phase - 2) * pcount * extent;
+              Request::send((char *)recv_buf + send_offset, pcount, dtype, dst, tag, comm);
+            }
+          }
+          mask >>= 1;
+        }
+      }
+    }
+
+    /* start binomial broadcast intra-communication inside each SMP nodes */
+    if (phase > 2) {
+      int num_core_in_current_smp = num_core;
+      if (inter_rank == (inter_comm_size - 1)) {
+        num_core_in_current_smp = comm_size - (inter_rank * num_core);
+      }
+      mask = 1;
+      while (mask < num_core_in_current_smp) {
+        if (intra_rank & mask) {
+          src = (inter_rank * num_core) + (intra_rank - mask);
+          recv_offset = (phase - 3) * pcount * extent;
+          Request::recv((char *)recv_buf + recv_offset, pcount, dtype, src, tag, comm,
+                   &status);
+          break;
+        }
+        mask <<= 1;
+      }
+      mask >>= 1;
+
+      while (mask > 0) {
+        dst = (inter_rank * num_core) + (intra_rank + mask);
+        if (dst < comm_size) {
+          send_offset = (phase - 3) * pcount * extent;
+          Request::send((char *)recv_buf + send_offset, pcount, dtype, dst, tag, comm);
+        }
+        mask >>= 1;
+      }
+    }
+  }                             // for phase
+
+  smpi_free_tmp_buffer(tmp_buf);
+  return MPI_SUCCESS;
+}