120 lines
2.5 KiB
C
120 lines
2.5 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <pthread.h>
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#include <unistd.h>
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/* Non standard include */
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#include <commtech.h>
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#include <specific_comm.h>
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void *create_comm_channel(void)
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{
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struct channel *channel;
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if (!posix_memalign((void *) &channel, CACHE_LINE_SIZE, sizeof(struct channel)))
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{
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if (!posix_memalign((void *) &channel->shared_space, CACHE_LINE_SIZE, SHARED_SPACE_SIZE))
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{
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unsigned int i;
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channel->head = 0;
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channel->tail = 0;
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for (i = 0; i < SHARED_SPACE_VOIDPTR; i++)
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channel->shared_space[i] = NULL;
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return channel;
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}
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else
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free(channel);
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}
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return NULL;
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}
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int end_producer(void *unused __attribute__ ((unused)))
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{
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return 0;
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}
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int destroy_comm_channel(void *channel)
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{
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free((void *) ((struct channel *) channel)->shared_space);
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free(channel);
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return 0;
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}
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int adjust_slip(struct channel *channel)
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{
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unsigned int dist, dist_old, unused;
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//puts("adjust_slip is called"); /* Must be removed after calibration */
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unused = 0;
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dist = (channel->head + SHARED_SPACE_VOIDPTR - channel->tail) % SHARED_SPACE_VOIDPTR;
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if (dist < DANGER)
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{
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dist_old = 0;
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do
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{
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unsigned int i;
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dist_old = dist;
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/*
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* I consider 20 as being the number of ++ which could
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* be done while one data is sent by the producer
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*/
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for (i = 0; i < 20 * ((GOOD + 1) - dist); i++)
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unused++;
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dist = (channel->head + SHARED_SPACE_VOIDPTR - channel->tail) % SHARED_SPACE_VOIDPTR;
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} while (dist < GOOD && dist_old < dist);
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}
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return unused;
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}
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void *recv_one_data(struct channel *channel)
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{
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void *result;
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static __thread int nb_iter = 0;
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if (nb_iter == ADJUST_FREQ)
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{
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adjust_slip(channel);
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nb_iter = 0;
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}
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while (1)
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{
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result = channel->shared_space[channel->tail];
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if (NULL == result)
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continue;
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channel->shared_space[channel->tail] = NULL;
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channel->tail = (channel->tail + 1) % SHARED_SPACE_VOIDPTR;
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break;
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}
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return result;
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}
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ssize_t recv_some_data(struct channel *channel, void **buf, size_t count)
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{
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unsigned int n;
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static __thread int nb_iter = 0;
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for(n = 0; n < count; n++, nb_iter++)
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{
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if (nb_iter % ADJUST_FREQ == 0)
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{
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adjust_slip(channel);
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nb_iter = 0;
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}
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/*
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* The behaviour of this is not documented but we know
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* the values inside buf won't change during this affectation
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*/
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*buf = channel->shared_space[channel->tail];
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if (NULL == *buf)
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break;
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buf++;
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channel->shared_space[channel->tail] = NULL;
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channel->tail = (channel->tail + 1) % SHARED_SPACE_VOIDPTR;
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}
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return n;
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}
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