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Improvements to mod_bert

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* Calculate sampling error rate over a time window

* Create the following variables to control bert testing behavior:
  bert_timeout_ms - Milliseconds to wait for bert sync before timing out
  bert_window_ms - Window of time to calculate sampling error rate percentage
  bert_max_err - Max percentage of error tolerated before going out of sync
  bert_hangup_on_error - Hangup when error occurs (Timeout or going out of sync)
This commit is contained in:
Moises Silva 2013-08-05 01:30:44 -04:00
parent fa3a1a0bdd
commit 66a9e12aa8
1 changed files with 102 additions and 36 deletions
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140
src/mod/applications/mod_bert/mod_bert.c
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@ -24,7 +24,7 @@
* Contributor(s):
* Moises Silva <moises.silva@gmail.com>
*
* mod_g711_bert -- Naive BERT tester
* mod_bert -- Naive BERT tester
*
*/
@ -34,40 +34,84 @@ SWITCH_MODULE_LOAD_FUNCTION(mod_bert_load);
SWITCH_MODULE_SHUTDOWN_FUNCTION(mod_bert_shutdown);
SWITCH_MODULE_DEFINITION(mod_bert, mod_bert_load, mod_bert_shutdown, NULL);
SWITCH_STANDARD_APP(g711_bert_function)
#define BERT_DEFAULT_WINDOW_MS 1000
#define BERT_DEFAULT_MAX_ERR 10.0
#define BERT_DEFAULT_TIMEOUT_MS 10000
SWITCH_STANDARD_APP(bert_test_function)
{
switch_status_t status;
switch_frame_t *read_frame = NULL, write_frame = { 0 };
switch_codec_implementation_t read_impl = { 0 };
switch_channel_t *channel = NULL;
const char *var = NULL;
int i = 0;
uint32_t interval = 0;
int synced = 0;
uint32_t ts = 0;
int32_t timeout_ms = 0;
struct {
uint64_t sync;
uint32_t bytes_since_sync;
uint32_t min_sync_samples;
uint32_t max_sync_err;
uint32_t sync_err;
int16_t tx_sample;
int16_t test_data;
uint32_t processed_samples;
uint32_t err_samples;
uint32_t window_ms;
uint32_t window_samples;
int16_t sequence_sample;
int16_t predicted_sample;
float max_err;
float max_err_hit;
float max_err_ever;
uint8_t in_sync;
uint8_t hangup_on_error;
switch_time_t timeout;
} bert;
memset(&bert, 0, sizeof(bert));
channel = switch_core_session_get_channel(session);
switch_channel_answer(channel);
switch_core_session_get_read_impl(session, &read_impl);
interval = read_impl.microseconds_per_packet / 1000;
memset(&bert, 0, sizeof(bert));
bert.window_ms = BERT_DEFAULT_WINDOW_MS;
bert.window_samples = switch_samples_per_packet(read_impl.samples_per_second, bert.window_ms);
bert.max_err = BERT_DEFAULT_MAX_ERR;
timeout_ms = BERT_DEFAULT_TIMEOUT_MS;
/* check if there are user-defined overrides */
if ((var = switch_channel_get_variable(channel, "bert_window_ms"))) {
int tmp = atoi(var);
if (tmp > 0) {
bert.window_ms = tmp;
bert.window_samples = switch_samples_per_packet(read_impl.samples_per_second, bert.window_ms);
}
}
if ((var = switch_channel_get_variable(channel, "bert_timeout_ms"))) {
int tmp = atoi(var);
if (tmp > 0) {
timeout_ms = tmp;
}
}
if ((var = switch_channel_get_variable(channel, "bert_max_err"))) {
double tmp = atoi(var);
if (tmp > 0) {
bert.max_err = (float)tmp;
}
}
if ((var = switch_channel_get_variable(channel, "bert_hangup_on_error"))) {
if (switch_true(var)) {
bert.hangup_on_error = 1;
}
}
bert.timeout = (switch_micro_time_now() + (timeout_ms * 1000));
write_frame.codec = switch_core_session_get_read_codec(session);
write_frame.data = switch_core_session_alloc(session, SWITCH_RECOMMENDED_BUFFER_SIZE);
write_frame.buflen = SWITCH_RECOMMENDED_BUFFER_SIZE;
bert.min_sync_samples = (read_impl.samples_per_packet * 40);
bert.max_sync_err = (read_impl.samples_per_packet * 20);
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG, "BERT Test Window=%ums/%u MaxErr=%f%%\n", bert.window_ms, bert.window_samples, bert.max_err);
if (bert.window_samples <= 0) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_ERROR, "Failed to compute BERT window samples!\n");
goto done;
}
while (switch_channel_ready(channel)) {
int16_t *read_samples = NULL;
int16_t *write_samples = NULL;
@ -79,30 +123,48 @@ SWITCH_STANDARD_APP(g711_bert_function)
read_samples = read_frame->data;
write_samples = write_frame.data;
for (i = 0; i < (read_frame->datalen / 2); i++) {
if (bert.sync < bert.min_sync_samples) {
if (bert.test_data == read_samples[i]) {
bert.sync++;
}
} else {
if (bert.sync == bert.min_sync_samples) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_WARNING, "G.711 synced (%lu)\n", bert.sync);
bert.bytes_since_sync = 0;
bert.sync_err = 0;
}
bert.bytes_since_sync++;
if (bert.test_data != read_samples[i]) {
bert.sync_err++;
if (bert.sync_err >= bert.max_sync_err) {
bert.sync = 0;
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_WARNING, "G.711 sync lost (%u)\n", bert.bytes_since_sync);
}
} else {
bert.sync++;
if (bert.window_samples == bert.processed_samples) {
/* Calculate error rate */
float err = ((float)((float)bert.err_samples / (float)bert.processed_samples) * 100.0);
if (err > bert.max_err) {
if (bert.in_sync) {
bert.in_sync = 0;
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_WARNING, "BERT Sync Lost: %f%% loss\n", err);
if (bert.hangup_on_error) {
switch_channel_hangup(channel, SWITCH_CAUSE_MEDIA_TIMEOUT);
}
}
bert.test_data = (read_samples[i] + 1);
write_samples[i] = bert.tx_sample++;
} else if (!bert.in_sync) {
bert.in_sync = 1;
synced = 1;
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_INFO, "BERT Sync\n");
bert.timeout = 0;
}
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG10, "Err=%f%% (%u/%u)\n", err, bert.err_samples, bert.processed_samples);
if (synced && err > bert.max_err_hit) {
bert.max_err_hit = err;
}
if (err > bert.max_err_ever) {
bert.max_err_ever = err;
}
bert.processed_samples = 0;
bert.err_samples = 0;
if (bert.timeout && !synced) {
switch_time_t now = switch_micro_time_now();
if (now >= bert.timeout) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_WARNING, "BERT Timeout\n");
if (bert.hangup_on_error) {
switch_channel_hangup(channel, SWITCH_CAUSE_MEDIA_TIMEOUT);
}
}
}
}
if (bert.predicted_sample != read_samples[i]) {
bert.err_samples++;
}
bert.predicted_sample = (read_samples[i] + 1);
write_samples[i] = bert.sequence_sample++;
bert.processed_samples++;
}
write_frame.datalen = read_frame->datalen;
@ -114,6 +176,10 @@ SWITCH_STANDARD_APP(g711_bert_function)
}
ts += read_impl.samples_per_packet;
}
done:
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session), SWITCH_LOG_DEBUG, "BERT Test Completed. MaxErr=%f%%\n", synced ? bert.max_err_hit : bert.max_err_ever);
}
SWITCH_MODULE_LOAD_FUNCTION(mod_bert_load)
@ -122,7 +188,7 @@ SWITCH_MODULE_LOAD_FUNCTION(mod_bert_load)
*module_interface = switch_loadable_module_create_module_interface(pool, modname);
SWITCH_ADD_APP(app_interface, "bert_test", "Start BERT Test", "Start BERT Test", g711_bert_function, "", SAF_NONE);
SWITCH_ADD_APP(app_interface, "bert_test", "Start BERT Test", "Start BERT Test", bert_test_function, "", SAF_NONE);
return SWITCH_STATUS_SUCCESS;
}