async_schedule.h

Go to the documentation of this file.

/***************************************************************************
 * include/stxxl/bits/algo/async_schedule.h
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2002 Roman Dementiev <[email protected]>
 * Copyright (C) 2009 Andreas Beckmann <[email protected]>
 *
 * Distributed under the Boost Software License, Version 1.0.
 * (See accompanying file LICENSE_1_0.txt or copy at
 * http://www.boost.org/LICENSE_1_0.txt)
 **************************************************************************/

#ifndef STXXL_ALGO_ASYNC_SCHEDULE_HEADER
#define STXXL_ALGO_ASYNC_SCHEDULE_HEADER

// Implements the "prudent prefetching" as described in
// D. Hutchinson, P. Sanders, J. S. Vitter: Duality between prefetching
// and queued writing on parallel disks, 2005
// DOI: 10.1137/S0097539703431573

#include <stxxl/bits/common/types.h>
#include <stxxl/bits/namespace.h>

STXXL_BEGIN_NAMESPACE

void compute_prefetch_schedule(
 const int_type* first,
 const int_type* last,
 int_type* out_first,
 int_type m,
 int_type D);

inline void compute_prefetch_schedule(
 int_type* first,
 int_type* last,
 int_type* out_first,
 int_type m,
 int_type D)
{
 compute_prefetch_schedule(static_cast<const int_type*>(first), last, out_first, m, D);
}

template <typename run_type>
void compute_prefetch_schedule(
 const run_type& input,
 int_type* out_first,
 int_type m,
 int_type D)
{
 const int_type L = input.size();
 int_type* disks = new int_type[L];
 for (int_type i = 0; i < L; ++i)
 disks[i] = input[i].bid.storage->get_physical_device_id();
 compute_prefetch_schedule(disks, disks + L, out_first, m, D);
 delete[] disks;
}

template <typename bid_iterator_type>
void compute_prefetch_schedule(
 bid_iterator_type input_begin,
 bid_iterator_type input_end,
 int_type* out_first,
 int_type m,
 int_type D)
{
 const int_type L = input_end - input_begin;
 int_type* disks = new int_type[L];
 int_type i = 0;
 for (bid_iterator_type it = input_begin; it != input_end; ++it, ++i)
 disks[i] = it->storage->get_physical_device_id();
 compute_prefetch_schedule(disks, disks + L, out_first, m, D);
 delete[] disks;
}

STXXL_END_NAMESPACE

#endif // !STXXL_ALGO_ASYNC_SCHEDULE_HEADER
// vim: et:ts=4:sw=4