early stop when all sequence reach EOS

[je1lee]

With model.generate() it takes too long even sequence generation have done earlier with EOS token. Because now, it generates til it reached to output_len

fix the generate method to stop when every sequence has generated EOS token

[je1lee]

@pengchongjin any idea for this?

[pengchongjin]

Thanks for the change. Could you please paste a few example outputs before and after this change?

Also please make sure to test both run.py and run_xla.py. Thanks!

[je1lee]

@pengchongjin test done with both scripts

BEFORE

model generates token regardless of eos token, so time spent in generation increases quadratically as output_len increases

AFTER

model stop generate when model samples out eos token time spent in generation remain still as output_len increases