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authorMichael Tatarinov <kukabu@gmail.com>2014-01-30 08:21:44 +0400
committerSteve Markgraf <steve@steve-m.de>2014-02-04 19:11:10 +0100
commit1cc9d64d98f572642f07dd55dff5ba29ace826b6 (patch)
treee97d101f4c8c874d01efa4dad56ef992ea752e66
parent2c171630fa8b0312161b87d57e1437bc658ed5a0 (diff)
rtl_test: refactoring and optimization for PPM error
Signed-off-by: Steve Markgraf <steve@steve-m.de>
-rw-r--r--src/rtl_test.c188
1 files changed, 97 insertions, 91 deletions
diff --git a/src/rtl_test.c b/src/rtl_test.c
index 987bb59..fd6e0eb 100644
--- a/src/rtl_test.c
+++ b/src/rtl_test.c
@@ -48,28 +48,23 @@
#define MHZ(x) ((x)*1000*1000)
#define PPM_DURATION 10
+#define PPM_DUMP_TIME 5
+
+static enum {
+ NO_BENCHMARK,
+ TUNER_BENCHMARK,
+ PPM_BENCHMARK
+} test_mode = NO_BENCHMARK;
static int do_exit = 0;
static rtlsdr_dev_t *dev = NULL;
-static int ppm_benchmark = 0;
-static int ppm_running = 0;
-static int64_t ppm_count = 0L;
-static int64_t ppm_total = 0L;
-uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
-
-long total_samples;
-long dropped_samples;
+static uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
-#ifndef _WIN32
-static struct timespec ppm_start;
-static struct timespec ppm_recent;
-static struct timespec ppm_now;
-#endif
+static uint32_t total_samples = 0;
+static uint32_t dropped_samples = 0;
-#ifdef __APPLE__
-static struct timeval tv;
-#endif
+static unsigned int ppm_duration = PPM_DURATION;
void usage(void)
{
@@ -79,9 +74,9 @@ void usage(void)
"\t[-s samplerate (default: 2048000 Hz)]\n"
"\t[-d device_index (default: 0)]\n"
"\t[-t enable Elonics E4000 tuner benchmark]\n"
- #ifndef _WIN32
- "\t[-p enable PPM error measurement]\n"
- #endif
+#ifndef _WIN32
+ "\t[-p[seconds] enable PPM error measurement (default: 10 seconds)]\n"
+#endif
"\t[-b output_block_size (default: 16 * 16384)]\n"
"\t[-S force sync output (default: async)]\n");
exit(1);
@@ -126,8 +121,8 @@ static void underrun_test(unsigned char *buf, uint32_t len, int mute)
bcnt++;
}
- total_samples += (long)len;
- dropped_samples += (long)lost;
+ total_samples += len;
+ dropped_samples += lost;
if (mute)
return;
if (lost)
@@ -135,77 +130,92 @@ static void underrun_test(unsigned char *buf, uint32_t len, int mute)
}
-static void ppm_clock_init(void)
+#ifndef _WIN32
+static int ppm_gettime(struct timespec *ts)
{
-#ifdef __APPLE__
- gettimeofday(&tv, NULL);
- ppm_recent.tv_sec = tv.tv_sec;
- ppm_recent.tv_nsec = tv.tv_usec*1000;
- ppm_start.tv_sec = tv.tv_sec;
- ppm_start.tv_nsec = tv.tv_usec*1000;
-#elif __unix__
- clock_gettime(CLOCK_REALTIME, &ppm_recent);
- clock_gettime(CLOCK_REALTIME, &ppm_start);
+ int rv = ENOSYS;
+
+#ifdef __unix__
+ rv = clock_gettime(CLOCK_MONOTONIC, ts);
+#elif __APPLE__
+ struct timeval tv;
+
+ rv = gettimeofday(&tv, NULL);
+ ts->tv_sec = tv.tv_sec;
+ ts->tv_nsec = tv.tv_usec * 1000;
#endif
+ return rv;
}
-#ifndef _WIN32
-static int ppm_report(void)
+static int ppm_report(uint64_t nsamples, uint64_t interval)
{
- int real_rate;
- int64_t ns;
- ns = 1000000000L * (int64_t)(ppm_recent.tv_sec - ppm_start.tv_sec);
- ns += (int64_t)(ppm_recent.tv_nsec - ppm_start.tv_nsec);
- real_rate = (int)(ppm_total * 1000000000L / ns);
- return (int)round((double)(1000000 * (real_rate - (int)samp_rate)) / (double)samp_rate);
+ double real_rate, ppm;
+
+ real_rate = nsamples * 1e9 / interval;
+ ppm = 1e6 * (real_rate / (double)samp_rate - 1.);
+ return (int)round(ppm);
}
-#endif
static void ppm_test(uint32_t len)
{
- int64_t ns;
-
- ppm_count += (int64_t)len;
-#ifndef _WIN32
- #ifndef __APPLE__
- clock_gettime(CLOCK_REALTIME, &ppm_now);
- #else
- gettimeofday(&tv, NULL);
- ppm_now.tv_sec = tv.tv_sec;
- ppm_now.tv_nsec = tv.tv_usec*1000;
- #endif
- if (ppm_now.tv_sec - ppm_recent.tv_sec > PPM_DURATION) {
- ns = 1000000000L * (int64_t)(ppm_now.tv_sec - ppm_recent.tv_sec);
- ns += (int64_t)(ppm_now.tv_nsec - ppm_recent.tv_nsec);
- printf("real sample rate: %i",
- (int)((1000000000L * ppm_count / 2L) / ns));
- #ifndef __APPLE__
- clock_gettime(CLOCK_REALTIME, &ppm_recent);
- #else
- gettimeofday(&tv, NULL);
- ppm_recent.tv_sec = tv.tv_sec;
- ppm_recent.tv_nsec = tv.tv_usec*1000;
- #endif
- ppm_total += ppm_count / 2L;
- ppm_count = 0L;
- printf(" cumulative ppm: %i\n", ppm_report());
+ static uint64_t nsamples = 0;
+ static uint64_t interval = 0;
+ static uint64_t nsamples_total = 0;
+ static uint64_t interval_total = 0;
+ struct timespec ppm_now;
+ static struct timespec ppm_recent;
+ static enum {
+ PPM_INIT_NO,
+ PPM_INIT_DUMP,
+ PPM_INIT_RUN
+ } ppm_init = PPM_INIT_NO;
+
+ ppm_gettime(&ppm_now);
+ if (ppm_init != PPM_INIT_RUN) {
+ /*
+ * Kyle Keen wrote:
+ * PPM_DUMP_TIME throws out the first N seconds of data.
+ * The dongle's PPM is usually very bad when first starting up,
+ * typically incorrect by more than twice the final value.
+ * Discarding the first few seconds allows the value to stabilize much faster.
+ */
+ if (ppm_init == PPM_INIT_NO) {
+ ppm_recent.tv_sec = ppm_now.tv_sec + PPM_DUMP_TIME;
+ ppm_init = PPM_INIT_DUMP;
+ return;
+ }
+ if (ppm_init == PPM_INIT_DUMP && ppm_recent.tv_sec < ppm_now.tv_sec)
+ return;
+ ppm_recent.tv_sec = ppm_now.tv_sec;
+ ppm_recent.tv_nsec = ppm_now.tv_nsec;
+ ppm_init = PPM_INIT_RUN;
+ return;
}
-#endif
+ nsamples += (uint64_t)(len / 2UL);
+ interval = (uint64_t)(ppm_now.tv_sec - ppm_recent.tv_sec);
+ if (interval < ppm_duration)
+ return;
+ interval *= 1000000000UL;
+ interval += (int64_t)(ppm_now.tv_nsec - ppm_recent.tv_nsec);
+ nsamples_total += nsamples;
+ interval_total += interval;
+ printf("real sample rate: %i current PPM: %i cumulative PPM: %i\n",
+ (int)((1000000000UL * nsamples) / interval),
+ ppm_report(nsamples, interval),
+ ppm_report(nsamples_total, interval_total));
+ ppm_recent.tv_sec = ppm_now.tv_sec;
+ ppm_recent.tv_nsec = ppm_now.tv_nsec;
+ nsamples = 0;
}
+#endif
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{
underrun_test(buf, len, 0);
-
- if (ppm_benchmark && !ppm_running) {
- ppm_clock_init();
- ppm_running = 1;
- return;
- }
-
- if (ppm_benchmark) {
+#ifndef _WIN32
+ if (test_mode == PPM_BENCHMARK)
ppm_test(len);
- }
+#endif
}
void e4k_benchmark(void)
@@ -259,9 +269,7 @@ int main(int argc, char **argv)
#ifndef _WIN32
struct sigaction sigact;
#endif
- int n_read;
- int r, opt;
- int i, tuner_benchmark = 0;
+ int n_read, r, opt, i;
int sync_mode = 0;
uint8_t *buffer;
int dev_index = 0;
@@ -270,7 +278,7 @@ int main(int argc, char **argv)
int count;
int gains[100];
- while ((opt = getopt(argc, argv, "d:s:b:tpS::")) != -1) {
+ while ((opt = getopt(argc, argv, "d:s:b:tp::Sh")) != -1) {
switch (opt) {
case 'd':
dev_index = verbose_device_search(optarg);
@@ -283,14 +291,17 @@ int main(int argc, char **argv)
out_block_size = (uint32_t)atof(optarg);
break;
case 't':
- tuner_benchmark = 1;
+ test_mode = TUNER_BENCHMARK;
break;
case 'p':
- ppm_benchmark = PPM_DURATION;
+ test_mode = PPM_BENCHMARK;
+ if (optarg)
+ ppm_duration = atoi(optarg);
break;
case 'S':
sync_mode = 1;
break;
+ case 'h':
default:
usage();
break;
@@ -345,7 +356,7 @@ int main(int argc, char **argv)
/* Set the sample rate */
verbose_set_sample_rate(dev, samp_rate);
- if (tuner_benchmark) {
+ if (test_mode == TUNER_BENCHMARK) {
if (rtlsdr_get_tuner_type(dev) == RTLSDR_TUNER_E4000)
e4k_benchmark();
else
@@ -360,12 +371,12 @@ int main(int argc, char **argv)
/* Reset endpoint before we start reading from it (mandatory) */
verbose_reset_buffer(dev);
- if (ppm_benchmark && !sync_mode) {
- fprintf(stderr, "Reporting PPM error measurement every %i seconds...\n", ppm_benchmark);
+ if ((test_mode == PPM_BENCHMARK) && !sync_mode) {
+ fprintf(stderr, "Reporting PPM error measurement every %i seconds...\n", ppm_duration);
fprintf(stderr, "Press ^C after a few minutes.\n");
}
- if (!ppm_benchmark) {
+ if (test_mode == NO_BENCHMARK) {
fprintf(stderr, "\nInfo: This tool will continuously"
" read from the device, and report if\n"
"samples get lost. If you observe no "
@@ -397,11 +408,6 @@ int main(int argc, char **argv)
if (do_exit) {
fprintf(stderr, "\nUser cancel, exiting...\n");
fprintf(stderr, "Samples per million lost (minimum): %i\n", (int)(1000000L * dropped_samples / total_samples));
-#ifndef _WIN32
- if (ppm_benchmark) {
- printf("Cumulative PPM error: %i\n", ppm_report());
- }
-#endif
}
else
fprintf(stderr, "\nLibrary error %d, exiting...\n", r);