Re: [quicwg/base-drafts] Remove ack_delay_exponent TP (#2670)

Jana Iyengar <> Mon, 22 July 2019 19:22 UTC

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From: Jana Iyengar <>
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Subject: Re: [quicwg/base-drafts] Remove ack_delay_exponent TP (#2670)
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In general, if CPU is a problem, there's a simple fix. Ignore ack delay
entirely. Your RTT values will be higher, causing recovery to take longer,
but that is the tradeoff. At any rate, this recovery time won't be worse
than TCP, since TCP includes receiver delays in its RTT estimates.

On Wed, Jul 10, 2019 at 7:40 AM Martin Thomson <>

> I'm fairly confident that these operations will be done on relatively
> small values, and so optimization to that degree will be possible. I plan
> to use Rust u128 values and to ignore the cost, but I realize that not
> every implementation can afford to spend upwards of 4 CPU cycles on an
> operation that you perform once every other packet.
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