T reduce( GlobalAddress<T> localizable ) {
CompletionEvent ce(cores() - 1);
T total = *(localizable.localize());
Core origin = mycore();
for (Core c=0; c<cores(); c++) {
if (c != origin) {
send_heap_message(c, [localizable, &ce, &total, origin]{
T val = *(localizable.localize());
send_heap_message(origin, [val,&ce,&total] {
total = ReduceOp(total, val);
ce.complete();
});
});
}
}
ce.wait();
return total;
}
void bucket_sort(GlobalAddress<S> array, size_t nelems, int (*Scmp)(const void*,const void*), size_t (*lobits)(S,int), int log2buckets, int log2maxkey ) {
double t, sort_time, histogram_time, allreduce_time, scatter_time, local_sort_scatter_time, put_back_time;
int LOBITS = log2maxkey - log2buckets;
size_t nbuckets = 1 << log2buckets;
GlobalAddress<bucket_t<S> > bucketlist = Grappa::global_alloc<bucket_t<S> >(nbuckets);
#ifdef DEBUG
for (size_t i=0; i<nbuckets; i++) {
GlobalAddress<bucket_t<S> > bi = bucketlist+i;
VLOG(1) << "bucket[" << i << "] on Node " << bi.core() << ", offset = " << bi.pointer() - bucketlist.localize(bi.core()) << ", ptr = " << bi.pointer();
}
#endif
sort_time = Grappa::walltime();
// initialize globals and histogram counts
// { setup_counts f(array, nbuckets, bucketlist); fork_join_custom(&f); }
on_all_cores([nbuckets]{
counts.resize(nbuckets);
offsets.resize(nbuckets);
for (size_t i=0; i<nbuckets; i++) {
counts[i] = 0;
}
});
t = Grappa::walltime();
// do local bucket counts
// forall_local<uint64_t,histogram>(array, nelems);
forall(array, nelems, [lobits,LOBITS](int64_t i, S& v) {
size_t b = lobits(v, LOBITS); // TODO decide how to compare general in pieces
counts[b]++;
});
histogram_time = Grappa::walltime() - t;
LOG(INFO) << "histogram_time: " << histogram_time;
t = Grappa::walltime();
// allreduce everyone's counts & compute global offsets (prefix sum)
// { aggregate_counts f; fork_join_custom(&f); }
on_all_cores([nbuckets] {
CHECK_EQ(nbuckets, counts.size());
// all nodes get total counts put into their counts array
allreduce_inplace<size_t,collective_add>(&counts[0], counts.size());
VLOG(1) << "after allreduce_inplace (just in case)";
// everyone computes prefix sum over buckets locally
offsets[0] = 0;
for (size_t i=1; i<offsets.size(); i++) {
offsets[i] = offsets[i-1] + counts[i-1];
}
});
allreduce_time = Grappa::walltime() - t;
LOG(INFO) << "allreduce_time: " << allreduce_time;
// allocate space in buckets
VLOG(3) << "allocating space...";
// forall_local<bucket_t,init_buckets>(bucketlist, nbuckets);
forall(bucketlist, nbuckets, [](int64_t id, bucket_t<S>& bucket){
// (global malloc doesn't call constructors)
new (&bucket) bucket_t<S>();
bucket.reserve(counts[id]);
});
VLOG(3) << "scattering...";
t = Grappa::walltime();
// scatter into buckets
// forall_local<uint64_t,scatter>(array, nelems);
forall(array, nelems, [bucketlist,lobits,LOBITS](int64_t s, int64_t n, S * first){
size_t nbuckets = counts.size();
for (int i=0; i<n; i++) {
auto v = first[i];
size_t b = lobits(v, LOBITS);
CHECK( b < nbuckets ) << "bucket id = " << b << ", nbuckets = " << nbuckets;
// ff_delegate<bucket_t,uint64_t,ff_append>(bucketlist+b, v);
auto destb = bucketlist+b;
delegate::call<async>(destb.core(), [destb,v]{
destb.pointer()->append(v);
});
}
});
scatter_time = Grappa::walltime() - t;
LOG(INFO) << "scatter_time: " << scatter_time;
t = Grappa::walltime();
// sort buckets locally
// forall_local<bucket_t,sort_bucket>(bucketlist, nbuckets);
/// Do some kind of local serial sort of a bucket
forall(bucketlist, nbuckets, [Scmp](int64_t bucket_id, bucket_t<S>& bucket){
if (bucket.size() == 0) return;
qsort(&bucket[0], bucket.size(), sizeof(S), Scmp);
});
local_sort_scatter_time = Grappa::walltime() - t;
LOG(INFO) << "local_sort_time: " << local_sort_scatter_time;
t = Grappa::walltime();
// redistribute buckets back into global array
// forall_local<bucket_t,put_back_bucket>(bucketlist, nbuckets);
/// Redistribute sorted buckets back into global array
forall(bucketlist, nbuckets, [array,bucketlist](int64_t b, bucket_t<S>& bucket) {
const size_t NBUF = BUFSIZE / sizeof(S);
DCHECK( b < counts.size() );
// TODO: shouldn't need to buffer this, but a bug of some sort is currently forcing us to limit the number of outstanding messages
//for_buffered(i, n, 0, bucket.size(), NBUF) {
// typename Incoherent<S>::WO c(array+offsets[b]+i, n, &bucket[i]);
// c.block_until_released();
// }
if ( bucket.size() > 0 ) {
typename Incoherent<S>::WO c(array+offsets[b], bucket.size(), &bucket[0]); // FIXME v is not in locale-shared-memory
c.block_until_released();
}
VLOG(3) << "bucket[" << b << "] release successful";
});
put_back_time = Grappa::walltime() - t;
LOG(INFO) << "put_back_time: " << put_back_time;
sort_time = Grappa::walltime() - sort_time;
LOG(INFO) << "total_sort_time: " << sort_time;
}