How to log speed (it/s)

How to log train and validation speed , e.g. self.log(‘speed’, xxx.speed)

the simplest way would be time each validation step, sum it all together and log it in on_validation_end hook :rabbit:
since v1.1.0 you shall be able to use self.log(...) even in any callback, am I correct @tchaton?

logging in callack is possible but not in on_validation_end callback hook. You can do that in on_validation_epoch_end.