Achieve minimum latency with CSI camera

hello d.razumov,

it’s almost impossible since you’re having camera sensor with 25-fps, each frame programming time takes 40-ms.

may I double confirm your use-case.
you had put your camera device target a stop-watch, render preview frames to a display monitor. in the meanwhile, you’re using another camera device (you should have high-speed camera to capture these timestamps) to take a picture to include both the timestamp of stop-watch and display monitor; then and you would like to reduce the latency of them.
the roughly pipeline shown as below, and you’re asking the latency from (A) to (B).
for example,

Sensor (A) → CSI → VI → ISP → Display (B)