The normal time range of BLE latency

[hmw]

Hi,
I am using Zephyr's BLE for transmission
In the peripheral, I record the time when I send the notify to cental (start time)
Then when I received the central write_without_response command, I also noted the time (end time)
Treat end_time - start_time as my transmission latency
I tested it 1000 times. Is it normal for his latency (as shown below) to jitter?

Y axis unit is ms

The x-axis unit is times

Thanks,

Poyi

[haakonsh]

I would assume so. You're asking and RTOS kernel to initiate a BLE notification, at what time that is executed is dependent on when you ask, tick rate of the kernel, how far into the current kernel 'time frame' you're in. Then you have response time of the peer BLE stack and application, BLE slave latency and connection interval, package loss, etc. The latency is fairly non-deterministic.