Re: Deadlocking in the transport
Martin Thomson <martin.thomson@gmail.com> Wed, 10 January 2018 22:08 UTC
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From: Martin Thomson <martin.thomson@gmail.com>
Date: Thu, 11 Jan 2018 09:08:00 +1100
Message-ID: <CABkgnnU3CQkvd7m+G80sCOPJfzb_=HonbRDSQJC8wqD_uWoj0w@mail.gmail.com>
Subject: Re: Deadlocking in the transport
To: Jana Iyengar <jri@google.com>
Cc: Charles 'Buck' Krasic <ckrasic@google.com>, QUIC WG <quic@ietf.org>
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On Thu, Jan 11, 2018 at 7:32 AM, Jana Iyengar <jri@google.com> wrote: >> What would this advice be? "Consume *all data* from higher priority >> streams before consuming data from lower priority streams?" > > Yes, to avoid deadlock. Priorities in h2 were always guidelines. You (and I think Buck as well) are suggesting that a dependency would be something that the transport could be bound by. That creates a dangerous schism between interpretation of priorities. In h2, if Y depends on X, a server can still send Y first. It will likely do so if Y is ready to go before X. That is, generally, h2 favours forward progress over strict adherence to priority ordering. I agree that the case that we're talking about at the transport layer is substantively different, but if we don't have other language for what we're doing, we create the potential for some really bad confusion about this mechanism. This is exacerbated by the fact that QUIC doesn't have any concrete priority mechanism built in. QUIC depends on the application protocol to feed it priority information, and that naturally tends toward having hq (and h2) dictate priority. hq will likely use the h2 idiom, which won't fit well with this notion.
- Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Brian Trammell (IETF)
- Re: Deadlocking in the transport Willy Tarreau
- Re: Deadlocking in the transport Jana Iyengar
- Re: Deadlocking in the transport Subodh Iyengar
- Re: Deadlocking in the transport Dmitri Tikhonov
- Re: Deadlocking in the transport Ian Swett
- Re: Deadlocking in the transport Mikkel Fahnøe Jørgensen
- Re: Deadlocking in the transport Mikkel Fahnøe Jørgensen
- Re: Deadlocking in the transport Charles 'Buck' Krasic
- Re: Deadlocking in the transport Ted Hardie
- Re: Deadlocking in the transport Jana Iyengar
- Re: Deadlocking in the transport Dmitri Tikhonov
- Re: Deadlocking in the transport Jana Iyengar
- Re: Deadlocking in the transport Dmitri Tikhonov
- Re: Deadlocking in the transport Jana Iyengar
- Re: Deadlocking in the transport Dmitri Tikhonov
- Re: Deadlocking in the transport Roberto Peon
- Re: Deadlocking in the transport Jana Iyengar
- Re: Deadlocking in the transport Mikkel Fahnøe Jørgensen
- Re: Deadlocking in the transport Dmitri Tikhonov
- Re: Deadlocking in the transport Christian Huitema
- Re: Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Dmitri Tikhonov
- Re: Deadlocking in the transport Jana Iyengar
- Re: Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Jana Iyengar
- RE: Deadlocking in the transport Mike Bishop
- Re: Deadlocking in the transport Mikkel Fahnøe Jørgensen
- Re: Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Mikkel Fahnøe Jørgensen
- Re: Deadlocking in the transport Martin Thomson
- RE: Deadlocking in the transport Lubashev, Igor
- Re: Deadlocking in the transport Dmitri Tikhonov
- Re: Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Jana Iyengar
- Re: Deadlocking in the transport Roberto Peon
- RE: Deadlocking in the transport Lubashev, Igor
- Re: Deadlocking in the transport Mirja Kühlewind
- Re: Deadlocking in the transport Roberto Peon
- Re: Deadlocking in the transport Roberto Peon
- Re: Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Jana Iyengar
- Re: Deadlocking in the transport Ian Swett
- Re: Deadlocking in the transport Martin Thomson
- Re: Deadlocking in the transport Mirja Kühlewind
- Re: Deadlocking in the transport Charles 'Buck' Krasic
- Re: Deadlocking in the transport Roberto Peon
- Re: Deadlocking in the transport Martin Thomson