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/***************************************************************************
* tests/io/test_sim_disk.cpp
*
* Part of the STXXL. See http://stxxl.sourceforge.net
*
* Copyright (C) 2002 Roman Dementiev <dementiev@mpi-sb.mpg.de>
*
* 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)
**************************************************************************/
// Tests sim_disk file implementation
// must be run on in-memory swap partition !
#include <cmath>
#include <stxxl/io>
#include <stxxl/random>
#include <stxxl/aligned_alloc>
using stxxl::file;
using stxxl::timestamp;
int main()
{
const stxxl::int64 disk_size = stxxl::int64(1024 * 1024) * 1024 * 40;
std::cout << sizeof(void*) << std::endl;
const int block_size = 4 * 1024 * 1024;
char* buffer = static_cast<char*>(stxxl::aligned_alloc<STXXL_BLOCK_ALIGN>(block_size));
memset(buffer, 0, block_size);
const char* paths[2] = { "/tmp/data1", "/tmp/data2" };
stxxl::sim_disk_file file1(paths[0], file::CREAT | file::RDWR | file::DIRECT, 0);
file1.set_size(disk_size);
stxxl::sim_disk_file file2(paths[1], file::CREAT | file::RDWR | file::DIRECT, 1);
file2.set_size(disk_size);
unsigned i = 0;
stxxl::int64 pos = 0;
stxxl::request_ptr req;
STXXL_MSG("Estimated time:" << block_size / stxxl::simdisk_geometry::s_average_speed);
STXXL_MSG("Sequential write");
for (i = 0; i < 40; i++)
{
double begin = timestamp();
req = file1.awrite(buffer, pos, block_size);
req->wait();
double end = timestamp();
STXXL_MSG("Pos: " << pos << " block_size:" << block_size << " time:" << (end - begin));
pos += 1024 * 1024 * 1024;
}
double sum = 0.;
double sum2 = 0.;
STXXL_MSG("Random write");
const unsigned int times = 80;
stxxl::random_number<> rnd;
for (i = 0; i < times; i++)
{
pos = (stxxl::int64)rnd(disk_size / block_size) * block_size;
double begin = timestamp();
req = file1.awrite(buffer, pos, block_size);
req->wait();
double diff = timestamp() - begin;
sum += diff;
sum2 += diff * diff;
STXXL_MSG("Pos: " << pos << " block_size:" << block_size << " time:" << (diff));
}
sum = sum / double(times);
sum2 = sum2 / double(times);
STXXL_CHECK(sum2 - sum * sum >= 0.0);
double err = sqrt(sum2 - sum * sum);
STXXL_MSG("Standard Deviation: " << err << " s, " << 100. * (err / sum) << " %");
stxxl::aligned_dealloc<STXXL_BLOCK_ALIGN>(buffer);
file1.close_remove();
file2.close_remove();
return 0;
}
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