rt_benchs/communication_techniques/src/calculation/calc_line.c

/*
 * Copyright (C) 2011 Thomas Preud'homme <thomas.preud-homme@lip6.fr>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <assert.h>

/* Non standard include */
#include <commtech.h>

#define CACHE_SIZE (32 * 1024)


static volatile uintptr_t *line_array;
static int write_idx, read_idx;
static int lines_per_calc;

#define CACHE_LINE_ENTRIES (CACHE_LINE_SIZE / sizeof(*line_array))

int init_calc(int lines_per_calc_param)
{
	unsigned int i;

	assert(!(CACHE_SIZE % (lines_per_calc_param * CACHE_LINE_SIZE)));
	lines_per_calc = lines_per_calc_param;
	write_idx = 0;
	read_idx = 0;
	srand(42);
	if (posix_memalign((void **) &line_array, CACHE_LINE_SIZE, CACHE_SIZE))
	{
		fprintf(stderr, "calc_line: Unable to allocate memory for random line-sized calculation\n");
		return -1;
	}
	for (i = 0; i < CACHE_SIZE / sizeof(*line_array); i++)
		line_array[i] = rand();
	return 0;
}

void **do_calc(void)
{
	int next_stop_read_idx, mres, cur_write_idx;

	mres = 0;
	next_stop_read_idx = read_idx + lines_per_calc * CACHE_LINE_ENTRIES;
	for (; read_idx < next_stop_read_idx; read_idx += CACHE_LINE_ENTRIES)
	{
		mres += line_array[read_idx];
		line_array[read_idx]++;
	}
	read_idx %= CACHE_SIZE / sizeof(*line_array);
	cur_write_idx = write_idx;
	write_idx++;
	write_idx %= CACHE_SIZE / sizeof(*line_array);
	line_array[cur_write_idx] = mres;
	return (void **) &line_array[cur_write_idx];
}

int end_calc(void)
{
	free((void *) line_array);
	return 0;
}