Method prefetch

dali/python/nvidia/dali/external_source.py:232–239

(self, pool, context_i, batch_size, epoch_idx)

        self.current_sample = 0

    def prefetch(self, pool, context_i, batch_size, epoch_idx):
        # NOTE We can't schedule more than what's on top of pipeline's prefetch queue, as the
        # entires in the pipeline are zero-copy and cannot be overwritten.
        context = pool.contexts[context_i]
        while context.scheduled_ahead < self.prefetch_queue_depth and self.schedule_batch(
            pool, context_i, context.scheduled_ahead, batch_size, epoch_idx
        ):
            pass

    def schedule_batch(self, pool, context_i, lead, batch_size, epoch_idx):
        """Schedule computing new batch from source callback by the parallel pool."""