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Re: a HTTP/2 window sizing dilemma!

From: Daniel Jeliński via curl-library <>
Date: Fri, 21 Feb 2020 10:04:28 +0100

Sounds like the problem HPN-SSH tried to solve:
I like their approach, but I'm not sure how they got hold of the
current TCP receive window size; the only value I could find was
receive buffer size, which is not necessarily relevant here.

If you decide to go with a static value, the default max TCP window
size on most machines is 32MB or less, and it is enough to saturate
1GBit link on the longest wired network (300 ms RTT, according to

Other than that, I'd love to know who is using curlopt_pause and how;
as far as I can tell, handling pause is only a problem on multiplexed
connections where we can't let the data rest in system buffers.

pt., 21 lut 2020 o 08:28 Daniel Stenberg via curl-library
<> napisał(a):
> On Thu, 20 Feb 2020, Daniel Stenberg via curl-library wrote:
> > But even so, the buffer size might very well be set to smaller sizes than
> > you'd want the HTTP/2 window size to be. Can we avoid a new option for
> > window size without having users suffer?
> Jay brought the suggestion [1] that we could just have it set fixed to (the
> much more sensible) 1MB as a middle ground - and I like the simplicity of
> that...
> [1]
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Received on 2020-02-21