MightyPork
/
rtl-sdr
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Perf: Replace rtl_tcp linked list with ring buffer

Browse Source 
Removed the linked list structure, locking, and malloc/free on each USB callback.
Replaced it with a non blocking ring buffer for performance.  This resulted
in a large performance improvement when using an Raspberry Pi or Raspberry Pi Zero W
as a rtl_tcp server.  The sample rate could be doubled and instead of wired ethernet
wifi could be used.  Frequnecy change lag was reduced greatly also.

Signed-off-by: Stephen Blinick <stephen@stesoft.com>
master
Stephen Blinick 6 years ago
parent f68bb2fa77
commit d0e7dcde04
1 changed files with 89 additions and 107 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 158
      src/rtl_tcp.c

158
src/rtl_tcp.c
Unescape View File

@ -61,15 +61,8 @@ static pthread_t command_thread;
static pthread_cond_t exit_cond;
static pthread_mutex_t exit_cond_lock;
static pthread_mutex_t ll_mutex;
static pthread_cond_t cond;
struct llist {
char *data;
size_t len;
struct llist *next;
};
typedef struct { /* structure size must be multiple of 2 bytes */
char magic[4];
uint32_t tuner_type;
@ -79,9 +72,17 @@ typedef struct { /* structure size must be multiple of 2 bytes */
static rtlsdr_dev_t *dev = NULL;
static int enable_biastee = 0;
static int global_numq = 0;
static struct llist *ll_buffers = 0;
static int llbuf_num = 500;
// Ring Buffer declarations
// 8MB appears to cover several seconds at high bitrates -- about as much lag as you'd want
#define RINGBUFSZ_INIT (8*1024*1024)
static int ringbuf_sz = RINGBUFSZ_INIT;
static int ringbuf_trimsz = 512*1024;
static unsigned char *ringbuf = NULL;
static volatile unsigned int ringbuf_head = 0;
static volatile unsigned int ringbuf_tail = 0;
static unsigned int total_radio_bytes = 0;
static unsigned int max_bytes_in_flight = 0;
static volatile int do_exit = 0;
@ -145,53 +146,60 @@ static void sighandler(int signum)
void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{
if(!do_exit) {
struct llist *rpt = (struct llist*)malloc(sizeof(struct llist));
rpt->data = (char*)malloc(len);
memcpy(rpt->data, buf, len);
rpt->len = len;
rpt->next = NULL;
static time_t lasttime = 0;
static int lastbytes = 0;
time_t curtime;
pthread_mutex_lock(&ll_mutex);
if (ll_buffers == NULL) {
ll_buffers = rpt;
} else {
struct llist *cur = ll_buffers;
int num_queued = 0;
if(!do_exit) {
unsigned int bufferleft;
while (cur->next != NULL) {
cur = cur->next;
num_queued++;
if (ringbuf == NULL)
{
printf("Allocate %d bytes for ringbuf.\n", ringbuf_sz);
ringbuf = (unsigned char*)malloc(ringbuf_sz);
}
if(llbuf_num && llbuf_num == num_queued-2){
struct llist *curelem;
free(ll_buffers->data);
curelem = ll_buffers->next;
free(ll_buffers);
ll_buffers = curelem;
bufferleft = ringbuf_sz - ((ringbuf_head < ringbuf_tail) ? (ringbuf_head - ringbuf_tail + ringbuf_sz) : (ringbuf_head - ringbuf_tail));
if (len < bufferleft)
{
if ((ringbuf_head+len) < (unsigned int)ringbuf_sz)
{
memcpy(((unsigned char*)(ringbuf+ringbuf_head)), buf, len);
}
else
{
memcpy(((unsigned char*)ringbuf+ringbuf_head), buf, ringbuf_sz-ringbuf_head);
memcpy((unsigned char*)ringbuf, buf+(ringbuf_sz-ringbuf_head), len-(ringbuf_sz-ringbuf_head));
}
ringbuf_head = (ringbuf_head + len) % ringbuf_sz;
}
else
{
printf("overrun: head=%d tail=%d, Trimming %d bytes from tail of buffer\n", ringbuf_head, ringbuf_tail, ringbuf_trimsz);
ringbuf_tail = (ringbuf_tail + ringbuf_trimsz) % ringbuf_sz;
}
cur->next = rpt;
if (num_queued > global_numq)
printf("ll+, now %d\n", num_queued);
else if (num_queued < global_numq)
printf("ll-, now %d\n", num_queued);
global_numq = num_queued;
total_radio_bytes += len;
curtime = time (NULL);
if ((curtime - lasttime) > 30)
{
int nsecs = curtime - lasttime;
int nbytes = total_radio_bytes - lastbytes;
int bytes_in_flight = (ringbuf_head - ringbuf_tail);
if (bytes_in_flight < 0)
bytes_in_flight = ringbuf_sz + bytes_in_flight;
lasttime=curtime;
lastbytes=total_radio_bytes;
printf(">> [ %3.2fMB/s ] [ bytes_in_flight(cur/max) = %4dK / %4dK ]\n",
(float)nbytes/(float)nsecs/1000.0/1000.0, bytes_in_flight/1024, max_bytes_in_flight/1024);
max_bytes_in_flight=0;
}
pthread_cond_signal(&cond);
pthread_mutex_unlock(&ll_mutex);
}
}
static void *tcp_worker(void *arg)
{
struct llist *curelem,*prev;
int bytesleft,bytessent, index;
int bytesleft, bytessent;
struct timeval tv= {1,0};
struct timespec ts;
struct timeval tp;
@ -202,36 +210,27 @@ static void *tcp_worker(void *arg)
if(do_exit)
pthread_exit(0);
pthread_mutex_lock(&ll_mutex);
gettimeofday(&tp, NULL);
ts.tv_sec = tp.tv_sec+5;
ts.tv_nsec = tp.tv_usec * 1000;
r = pthread_cond_timedwait(&cond, &ll_mutex, &ts);
if(r == ETIMEDOUT) {
pthread_mutex_unlock(&ll_mutex);
printf("worker cond timeout\n");
sighandler(0);
pthread_exit(NULL);
}
curelem = ll_buffers;
ll_buffers = 0;
pthread_mutex_unlock(&ll_mutex);
while(curelem != 0) {
bytesleft = curelem->len;
index = 0;
bytessent = 0;
while(bytesleft > 0) {
bytesleft = (ringbuf_head < ringbuf_tail) ?
(ringbuf_head - ringbuf_tail + ringbuf_sz) :
(ringbuf_head - ringbuf_tail);
while (bytesleft > 0)
{
FD_ZERO(&writefds);
FD_SET(s, &writefds);
tv.tv_sec = 1;
tv.tv_usec = 0;
r = select(s+1, NULL, &writefds, NULL, &tv);
if(r) {
bytessent = send(s, &curelem->data[index], bytesleft, 0);
unsigned int sendchunk;
if (ringbuf_tail < ringbuf_head)
sendchunk = ringbuf_head - ringbuf_tail;
else
sendchunk = ringbuf_sz - ringbuf_tail;
if (sendchunk > max_bytes_in_flight)
max_bytes_in_flight = sendchunk;
bytessent = send(s, (unsigned char*)(ringbuf+ringbuf_tail), sendchunk, 0);
bytesleft -= bytessent;
index += bytessent;
ringbuf_tail = (ringbuf_tail + bytessent) % ringbuf_sz;
}
if(bytessent == SOCKET_ERROR || do_exit) {
printf("worker socket bye\n");
@ -239,11 +238,6 @@ static void *tcp_worker(void *arg)
pthread_exit(NULL);
}
}
prev = curelem;
curelem = curelem->next;
free(prev->data);
free(prev);
}
}
}
@ -397,7 +391,7 @@ int main(int argc, char **argv)
struct sigaction sigact, sigign;
#endif
while ((opt = getopt(argc, argv, "a:p:f:g:s:b:n:d:P:T")) != -1) {
while ((opt = getopt(argc, argv, "a:p:f:g:s:b:d:P:T")) != -1) {
switch (opt) {
case 'd':
dev_index = verbose_device_search(optarg);
@ -421,9 +415,6 @@ int main(int argc, char **argv)
case 'b':
buf_num = atoi(optarg);
break;
case 'n':
llbuf_num = atoi(optarg);
break;
case 'P':
ppm_error = atoi(optarg);
break;
@ -510,7 +501,6 @@ int main(int argc, char **argv)
fprintf(stderr, "WARNING: Failed to reset buffers.\n");
pthread_mutex_init(&exit_cond_lock, NULL);
pthread_mutex_init(&ll_mutex, NULL);
pthread_mutex_init(&exit_cond_lock, NULL);
pthread_cond_init(&cond, NULL);
pthread_cond_init(&exit_cond, NULL);
@ -590,24 +580,16 @@ int main(int argc, char **argv)
closesocket(s);
printf("all threads dead..\n");
curelem = ll_buffers;
ll_buffers = 0;
while(curelem != 0) {
prev = curelem;
curelem = curelem->next;
free(prev->data);
free(prev);
}
do_exit = 0;
global_numq = 0;
}
out:
rtlsdr_close(dev);
closesocket(listensocket);
closesocket(s);
if (ringbuf)
free(ringbuf);
#ifdef _WIN32
WSACleanup();
#endif

Write Preview
Loading…
Cancel
Save