On Mon, 24 Nov 2025 20:27:57 GMT, Volkan Yazici <[email protected]> wrote:
>> Modify the PacketTransmissionTask to update the current deadline (`now`) >> between loop iterations. >> >> This fixes the deadlock issue which happened when the next deadline was >> equal to the current one, but no progress could be made because the pacer >> quota only increases as time passes. >> >> No new test; the issue was extremely rare. Existing tests continue to pass. > > @djelinski, amazing catch! :exploding_head: > > I'd really appreciate it if you can share a bit about how you troubleshoot > it. Which diagnostics knobs did you turn? Which log patterns made you suspect > the `congestionController.updatePacer(now)` line? @vy I observed a similar issue when I was writing the pacer code. There, the clock was actually running backwards, so it was happening more frequently, and was easier to catch using the quic:timer log. Here, adding any extra diagnostics changed the timing and made the issue go away, so I only measured the rtt and the pacing interval on a few machines, and found that at least in some cases the interval was in single nanosecond range. ------------- PR Comment: https://git.openjdk.org/jdk/pull/28462#issuecomment-3574343060
