feat(s2n-quic-dc): Increase background handshake jitter #2670
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This decreases the simultaneous concurrency we should expect by further distributing background handshakes across every minute by spreading both the start time of our cleaner loop (now starting at ~any millisecond) and the individual handshakes to smaller batches. In practice simultaneous handshakes aren't particularly advantageous (we have low roundtrip times, so handshake latency is dominated by the single CPU thread performing them) so reducing batch size makes sense to help improve latencies.
maddeleine
approved these changes
Jun 16, 2025
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Release Summary:
Resolved issues:
n/a
Description of changes:
This decreases the simultaneous concurrency we should expect by further distributing background handshakes across every minute by spreading both the start time of our cleaner loop (now starting at ~any millisecond) and the individual handshakes to smaller batches.
In practice simultaneous handshakes aren't particularly advantageous (we have low roundtrip times, so handshake latency is dominated by the single CPU thread performing them) so reducing batch size makes sense to help improve latencies.
Call-outs:
We don't have a good test bed for this change -- our primary tests are about the application-forced handshakes, not the background rate, and the background rate observations from them aren't necessarily reflective of production. That said, this should be essentially "purely good", and we will notice if it produces some unexpected results in our poor test bed.
Testing:
Just changing constants that aren't specifically tested. I'm hoping to test this in our test bed but wanted to get this posted in the meantime for initial review.
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.