io/test_io_sizes.cpp

This tests the maximum chunk size that a file type can handle with a single request.

/***************************************************************************
 * io/test_io_sizes.cpp
 *
 * Part of the STXXL. See http://stxxl.sourceforge.net
 *
 * Copyright (C) 2010 Johannes Singler <[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)
 **************************************************************************/

#include <stxxl/io>
#include <stxxl/aligned_alloc>
#include <stxxl/bits/mng/mng.h>



int main(int argc, char ** argv)
{
 if (argc < 4)
 {
 std::cout << "Usage: " << argv[0] << " filetype tempfile maxsize" << std::endl;
 return -1;
 }

 using stxxl::uint64;

 uint64 max_size = stxxl::atoint64(argv[3]);
 uint64 * buffer = (uint64 *)stxxl::aligned_alloc<4096>(max_size);

 try
 {
 stxxl::compat_unique_ptr<stxxl::file>::result file(
 stxxl::create_file(argv[1], argv[2], stxxl::file::CREAT | stxxl::file::RDWR | stxxl::file::DIRECT));
 file->set_size(max_size);

 stxxl::request_ptr req;
 stxxl::stats_data stats1(*stxxl::stats::get_instance());
 for (uint64 size = 4096; size < max_size; size *= 2)
 {
 //generate data
 for (uint64 i = 0; i < size / sizeof(uint64); ++i)
 buffer[i] = i;

 //write
 STXXL_MSG(stxxl::add_IEC_binary_multiplier(size, "B") << "are being written at once");
 req = file->awrite(buffer, 0, size, stxxl::default_completion_handler());
 wait_all(&req, 1);

 //fill with wrong data
 for (uint64 i = 0; i < size / sizeof(uint64); ++i)
 buffer[i] = 0xFFFFFFFFFFFFFFFFull;

 //read again
 STXXL_MSG(stxxl::add_IEC_binary_multiplier(size, "B") << "are being read at once");
 req = file->aread(buffer, 0, size, stxxl::default_completion_handler());
 wait_all(&req, 1);

 //check
 bool wrong = false;
 for (uint64 i = 0; i < size / sizeof(uint64); ++i)
 if (buffer[i] != i)
 {
 STXXL_ERRMSG("Read inconsistent data at position " << i * sizeof(uint64));
 wrong = true;
 break;
 }

 if (wrong)
 break;
 }
 std::cout << stxxl::stats_data(*stxxl::stats::get_instance()) - stats1;

 file->remove();
 }
 catch (stxxl::io_error e)
 {
 std::cerr << e.what() << std::endl;
 }

 stxxl::aligned_dealloc<4096>(buffer);

 return 0;
}
// vim: et:ts=4:sw=4