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.
so,
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)