At Uber, we are seeing an increasing demand for Kafka at-least-once delivery (asks=all). So far, we are running a dedicated at-least-once Kafka cluster with special settings. With a very low workload, the dedicated at-least-once cluster has been working well for more than a year. When trying to allow at-least-once producing on the regular Kafka clusters, the producing performance was the main concern. We spent some effort on this issue in the recent months, and managed to reduce at-least-once producer latency by about 80% with code changes and configuration tuning. When acks=0, these improvements also help increasing Kafka throughput and reducing Kafka end-to-end latency.