SFT training doesn't fully go through all samples

Current training uses ConstantLengthDataset. This dataset return fixed length of tokens (2048) in every step, however, the total number of steps are calculated based on the number of samples. I checked some samples and found that quite a few of them are much longer than 2048 (~7000), this means that some of the samples have never been seen in one epoch of training.

Could you please verify if my understanding is correct?

Thanks, appreciate.