Hi all, There were several configuration defaults that were changed with the release of 4.0.0 [1], I wonder if one or more of them could be affecting your observed end-to-end latency. Notably, the linger.ms on the producer side has increased from 0ms to 5ms. You may consider running 4.0.0 clients but with linger.ms set to 0 to see if that resolves this latency regression.
Thanks, Greg [1] https://cwiki.apache.org/confluence/display/KAFKA/KIP-1030%3A+Change+constraints+and+default+values+for+various+configurations On Thu, Aug 21, 2025 at 3:40 AM Daniel Germon <daniel.ger...@lmax.com.invalid> wrote: > Hi Paul, > > Thank you for taking the time to reply! I have just ran the benchmarks > using the v4.0.0 clients and if anything the latencies are actually worse > than on client v3.9.1: > > > Kafka broker 3.9.1 client 3.9.1 > > 50th percentile: 297 us > 90th percentile: 366 us > 99th percentile: 528 us > 99.9th percentile: 1,460 us > > Kafka broker 3.9.1 client 4.0.0 > > 50th percentile: 3,295 us > 90th percentile: 5,418 us > 99th percentile: 5,712 us > 99.9th percentile: 6,602 us > > Kafka broker 4.0.0 client 3.9.1 > > 50th percentile: 8,178 us > 90th percentile: 10,355 us > 99th percentile: 11,042 us > 99.9th percentile: 13,638 us > > Kafka broker 4.0.0 client 4.0.0 > > 50th percentile: 10,889 us > 90th percentile: 13,914 us > 99th percentile: 15,750 us > 99.9th percentile: 18,167 us > > I did run the internal kafka-e2e-latency tool however did not see any > noticeable difference, I believe this is because the tool is waiting for a > record to be received before sending another and so overall the throughput > would be lower than the setup I mention. > > Looking forward to see if you notice anything on your internal benchmarks. > > Regards, > Dan > > This message and its attachments are confidential, may not be disclosed or > used by any person other than the addressee and are intended only for the > named recipient(s). If you are not the intended recipient, please notify > the sender immediately and delete any copies of this message. > > LMAX Group is the holding company of LMAX Exchange, LMAX Global and LMAX > Digital. Our registered address is Yellow Building, 1A Nicholas Road, > London W11 4AN. >
