Hi Luke, > Under some conditions (especially high request rate), H3 connections simply > stall. This appears to be more prevalent in some browsers than others (Safari > on iOS is the worst offender), and appears to coincide with high packet_loss > in `show quic`.
Out of curiosity, what version of HAProxy are you running? I don’t have a magic answer but in https://github.com/haproxy/haproxy/issues/2095#issuecomment-1570547484 we’ve been looking at performance issues with H3/QUIC over time, and there’s a couple of workarounds currently relevant (~ from the comment linked), notably to use a short timeout connect (currently using 500ms here), and to comment out timeout client-fin. I see you explicitly set per-connection socket ownership, which is definitely the right thing to do, but you should check that it is actually working « for real » and not silently disabled due to permissions somewhere inside the worker processes. To do that, have a look at the output of ‘show fd’ and check that H3 conns aren’t all with fd=-1 (instead it should be a different positive fd number per H3 conn) I’d definitely like to see the JSFiddle if there’s a trick to the kind of request affected to see if I can reproduce it on our nodes. Regards, Tristan
