Hi, I read through the previous answers several times again and did some progress. I found out that the valid codec_ms values are <10ms,60ms> and using lower values will not work.
80 means a hardware interrupt is received every 10ms with 80 bytes per time slot. This is the recommended mode. A value of 40 will increase interrupt load and not necesarily reduce your latency, you must reduce the "user period", which is how often the driver will deliver media/data to the user application. This is done using sangoma_tdm_set_usr_period().
The codec_ms is used to call sangoma_tdm_set_usr_period(). This is how often the driver will deliver data to the user application (for example, waking it up from select()).
In each of the the test below the codec_ms was set to 1 with hope of fastest data delivery, however this resulted to 20ms codec_ms which is default.
Please, have a look at the results with various parameters used: mtu:80 txqueue_size=1 rxqueue_size=1 one-direction delay=60ms round-trip delay=120ms mtu:80 txqueue_size=2 rxqueue_size=2 one-direction delay=80ms round-trip delay=160ms mtu:80 txqueue_size=10 rxqueue_size=10 one-direction delay=240ms round-trip delay=480ms mtu:40 txqueue_size=1 rxqueue_size=1 one-direction delay=40ms round-trip delay=80ms mtu:40 txqueue_size=2 rxqueue_size=2 one-direction delay=60ms round-trip delay=120ms mtu:40 txqueue_size=5 rxqueue_size=5 one-direction delay=120ms round-trip delay=240ms mtu:16 txqueue_size=1 rxqueue_size=1 one-direction delay=30ms round-trip delay=60ms mtu:8 txqueue_size=1 rxqueue_size=1 one-direction delay=25ms round-trip delay=50ms mtu:8 txqueue_size=10 rxqueue_size=10 one-direction delay=205ms round-trip delay=410ms
Updated test result with the codec_ms=10 is following: mtu:16 txqueue_size=1 rxqueue_size=10 one-direction delay=20ms round-trip delay=50ms mtu:80 txqueue_size=1 rxqueue_size=10 one-direction delay=56ms round-trip delay=110ms However, this is still not 10ms with the default MTU:80 and codec_ms:10 :( Anyway, is it a good idea to use so assymetric tx/rx queue sizes? with best regards Juraj