/*
- * Copyright (C) 1997-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 1997-2012 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
#include "server.cmdline.h"
#include "list.h"
#include "send.h"
+#include "sched.h"
#include "vss.h"
#include "ipc.h"
#include "fd.h"
-#include "sched.h"
extern struct misc_meta_data *mmd;
static void compute_group_size(struct vss_task *vsst, struct fec_group *g,
int max_bytes)
{
+ char *buf;
+ size_t len;
int i, max_chunks = PARA_MAX(1LU, 150 / tv2ms(vss_chunk_time()));
+ if (g->first_chunk == 0) {
+ g->num_chunks = 1;
+ vss_get_chunk(0, vsst, &buf, &len);
+ g->bytes = len;
+ return;
+ }
+
g->num_chunks = 0;
g->bytes = 0;
/*
* of exactly one chunk for these audio formats.
*/
for (i = 0;; i++) {
- char *buf;
- size_t len;
int chunk_num = g->first_chunk + i;
if (g->bytes > 0 && i >= max_chunks) /* duration limit */
{
int ret, i, k, n, data_slices;
size_t len;
- char *buf;
+ char *buf, *p;
struct fec_group *g = &fc->group;
if (fc->state == FEC_STATE_NONE) {
assert(i == g->num_header_slices - 1);
}
- /* setup data slices */
+ /*
+ * Setup data slices. Note that for ogg streams chunk 0 points to a
+ * buffer on the heap rather than to the mapped audio file.
+ */
vss_get_chunk(g->first_chunk, vsst, &buf, &len);
- for (; i < g->num_header_slices + data_slices; i++) {
- if (buf + g->slice_bytes > vsst->map + mmd->size) {
+ for (p = buf; i < g->num_header_slices + data_slices; i++) {
+ if (p + g->slice_bytes > buf + g->bytes) {
/*
- * Can not use the memory mapped audio file for this
- * slice as it goes beyond the map.
+ * We must make a copy for this slice since using p
+ * directly would exceed the buffer.
*/
- uint32_t payload_size = vsst->map + mmd->size - buf;
- memcpy(fc->extra_src_buf, buf, payload_size);
+ uint32_t payload_size = buf + g->bytes - p;
+ assert(payload_size + FEC_HEADER_SIZE <= fc->mps);
+ memcpy(fc->extra_src_buf, p, payload_size);
if (payload_size < g->slice_bytes)
memset(fc->extra_src_buf + payload_size, 0,
g->slice_bytes - payload_size);
i++;
break;
}
- fc->src_data[i] = (const unsigned char *)buf;
- buf += g->slice_bytes;
+ fc->src_data[i] = (const unsigned char *)p;
+ p += g->slice_bytes;
}
if (i < k) {
/* use arbitrary data for all remaining slices */
return 1;
}
+#ifndef MAP_POPULATE
+#define MAP_POPULATE 0
+#endif
+
static void recv_afs_result(struct vss_task *vsst, fd_set *rfds)
{
int ret, passed_fd, shmid;
}
mmd->size = statbuf.st_size;
mmd->mtime = statbuf.st_mtime;
- ret = para_mmap(mmd->size, PROT_READ, MAP_PRIVATE, passed_fd,
- 0, &vsst->map);
+ ret = para_mmap(mmd->size, PROT_READ, MAP_PRIVATE | MAP_POPULATE,
+ passed_fd, 0, &vsst->map);
if (ret < 0)
goto err;
close(passed_fd);
senders[i].send(mmd->current_chunk, mmd->chunks_sent,
buf, len, vsst->header_buf, vsst->header_len);
}
+ /*
+ * Prefault next chunk(s)
+ *
+ * If the backing device of the memory-mapped audio file is
+ * slow and read-ahead is turned off or prevented for some
+ * reason, e.g. due to memory pressure, it may take much longer
+ * than the chunk interval to get the next chunk on the wire,
+ * causing buffer underruns on the client side. Mapping the
+ * file with MAP_POPULATE seems to help a bit, but it does not
+ * eliminate the delays completely. Moreover, it is supported
+ * only on Linux. So we do our own read-ahead here.
+ */
+ if (mmd->current_chunk > 0) { /* chunk 0 might be on the heap */
+ buf += len;
+ for (i = 0; i < 5 && buf < vsst->map + mmd->size; i++) {
+ __a_unused volatile char x = *buf;
+ buf += 4096;
+ }
+ }
mmd->chunks_sent++;
mmd->current_chunk++;
}
* Initialize the virtual streaming system task.
*
* \param afs_socket The fd for communication with afs.
+ * \param s The scheduler to register the vss task to.
*
* This also initializes all supported senders and starts streaming
* if the --autoplay command line flag was given.
*/
-void init_vss_task(int afs_socket)
+void init_vss_task(int afs_socket, struct sched *s)
{
static struct vss_task vss_task_struct, *vsst = &vss_task_struct;
int i;
&vsst->data_send_barrier);
}
sprintf(vsst->task.status, "vss task");
- register_task(&vsst->task);
+ register_task(s, &vsst->task);
}