Re: Deadlocking in the transport

Martin Thomson <martin.thomson@gmail.com> Thu, 11 January 2018 17:55 UTC

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From: Martin Thomson <martin.thomson@gmail.com>
Date: Fri, 12 Jan 2018 04:55:03 +1100
Message-ID: <CABkgnnVQgr5=_uJTtmAhxKxG-3VMM2UtHQdCNEhPPW8kmS8_fQ@mail.gmail.com>
Subject: Re: Deadlocking in the transport
To: Mike Bishop <mbishop@evequefou.be>, Martin Thomson <martin.thomson@gmail.com>, Jana Iyengar <jri@google.com>, QUIC WG <quic@ietf.org>, "Charles 'Buck' Krasic" <ckrasic@google.com>
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Mike's point is that we didn't address this particular problem in h2.
We left it up to implementations to manage.

It's possible that we had this problem of dependencies between
streams, but only at the highest layers (that is, above HTTP) where
the problem already has well-established patterns for managing it.
Those being firmly along the lines of "don't do that".

On Thu, Jan 11, 2018 at 4:52 PM, Dmitri Tikhonov
<dtikhonov@litespeedtech.com>; wrote:
> On Wed, Jan 10, 2018 at 10:55:46PM +0000, Mike Bishop wrote:
>> No disagreement.  When choosing which stream *with pending data* to make
>> progress on, I think choosing the higher-priority stream is necessary
>> rather than advisory.  With H2, we're talking about client preferences
>> about server responses which might not be ready yet, so it's always
>> advisory to the server.  Here, we're talking about the application's
>> preferences about its own data that it has already handed off.
>> That's something that happened within the HTTP/2 implementation,
>          ^^^^^^^^^^^^^^^^^^^^^^^
>> so there was no agreement or contract needed.
>
> What is that something that happened? and to which HTTP/2 implementation?
>
>   - Dmitri.