Bun performance issues with http-proxy-3 (only in Mac OS?)

[johnp789]

Great work on http-proxy-3!

I've been trying out Bun with several different things, and the benchmark in http-proxy-3 appears to expose a serious performance issue in Bun. On an M1 (ARM64) MacBook Pro, node 22 running proxy.js handles over 1800 req/s with 99.9% of requests having sub-100ms response times. Bun, on the other hand, has latency spikes all the way to 5s and struggles to handle 100 req/s. I'm testing with oha on the localhost interface.

Has anyone looked into what http-proxy-3 does that Bun isn't handling very well? There's an old issue in the Bun repo which describes delayed responses when using http-proxy, so that might be hitting the same issue.

[Edit to add more results....] On an Intel-based laptop in WSL2, this performance issue with Bun goes away completely. I'm seeing 5,610 req/s with Node 22 and 12,123 req/s with Bun 1.3 there.

[Edited again....] I tried running the benchmark on EC2 Graviton2 and Graviton4 instances, and on both of those, Bun ran the benchmark well. Now, I have to suspect the issue is either Mac OS or something very specific to my MacBook Pro.

[williamstein]

I don't have anything useful to add, but appreciate the data points.