Re: [quicwg/base-drafts] QUIC PTO is too conservative, causing a measurable regression in tail latency (#3526)

Martin Thomson <> Thu, 28 May 2020 01:23 UTC

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Date: Wed, 27 May 2020 18:23:26 -0700
From: Martin Thomson <>
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Subject: Re: [quicwg/base-drafts] QUIC PTO is too conservative, causing a measurable regression in tail latency (#3526)
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> I ran a test for 4 days on a major country

This probably shouldn't make me nervous, but it still does.  But I still greatly appreciate the data.

For my own peace of mind (though you will never alleviate the nervousness), can you confirm that you track both observed loss rates AND the rate of spurious retransmission?  It strikes me that there would be high correlation between improvements in latency and real loss, so the loss rates probably don't change except where the faster transmission coincides with true congestion (which I would expect to be undetectable), and the same is likely also true for spurious retransmission, but I just wanted to confirm.

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