Re: Extensible Priorities and Reprioritization
Kinuko Yasuda <kinuko@chromium.org> Wed, 10 June 2020 21:49 UTC
Return-Path: <ietf-http-wg-request+bounce-httpbisa-archive-bis2juki=lists.ie@listhub.w3.org>
X-Original-To: ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com
Delivered-To: ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4B2683A1551 for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Wed, 10 Jun 2020 14:49:03 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.749
X-Spam-Level:
X-Spam-Status: No, score=-2.749 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.249, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=chromium.org
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id CyKz_6Q1m4p3 for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Wed, 10 Jun 2020 14:49:01 -0700 (PDT)
Received: from lyra.w3.org (lyra.w3.org [128.30.52.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id D9DA33A1550 for <httpbisa-archive-bis2Juki@lists.ietf.org>; Wed, 10 Jun 2020 14:49:00 -0700 (PDT)
Received: from lists by lyra.w3.org with local (Exim 4.92) (envelope-from <ietf-http-wg-request@listhub.w3.org>) id 1jj8Y5-0005XM-B2 for ietf-http-wg-dist@listhub.w3.org; Wed, 10 Jun 2020 21:46:17 +0000
Resent-Date: Wed, 10 Jun 2020 21:46:17 +0000
Resent-Message-Id: <E1jj8Y5-0005XM-B2@lyra.w3.org>
Received: from titan.w3.org ([128.30.52.76]) by lyra.w3.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from <kinuko@google.com>) id 1jj8Y4-0005Wb-1Z for ietf-http-wg@listhub.w3.org; Wed, 10 Jun 2020 21:46:16 +0000
Received: from mail-io1-xd36.google.com ([2607:f8b0:4864:20::d36]) by titan.w3.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from <kinuko@google.com>) id 1jj8Y2-0002Fi-8l for ietf-http-wg@w3.org; Wed, 10 Jun 2020 21:46:15 +0000
Received: by mail-io1-xd36.google.com with SMTP id d5so4053637ios.9 for <ietf-http-wg@w3.org>; Wed, 10 Jun 2020 14:46:13 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=v5x8wVvDe1vwqDUvSE3ydHMhtmifCpp4eYhU7BM0Ihc=; b=XvLivPhh7f61fAOQmticZZkD63cfjmt+a+mYVzZ+eo45umQp5T1iWslHJ/WJE1l9yq pt6NTyOdORh7zcJRxUkfTw7DD/dcZ5G19gAWs22fKivERbg6ihxGy59T2YBx1ZzYQp8q uaKOrUD13YAdf1eER53CxsP3MtVzsvsflLLiM=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=v5x8wVvDe1vwqDUvSE3ydHMhtmifCpp4eYhU7BM0Ihc=; b=NuVzwIWPThWnTz8MHfbRK1pcmv5Vzw3sD7FbidtjmcdJXa0oDz/uqil5sn/jf4hkt7 Dbp309+QWOlXG+NtxDsYSk4kz9lmRywNWQhM96bkIy8xA4X0LhGHDlzFoDl8pf89J9qA HBtRlKDQCRN8vD3HHQBnTe/rfOcRD+3RxzQpZYPDu9y/HnKhwtUpN0onh2mKwhkwoK5S PNh6BPAauH6qhiUAJ02DaSJyZpdLw0lrx42CG2UIbSl4bafoP0PKnZ3fNJMxMMV1dGbg k/pa7A/N3hMhm9Zuh3UPTJfzW53Y6JtEfGEE5TBVytXtfxVR8OtSh8JT9MFW9N3T/yIy D5ag==
X-Gm-Message-State: AOAM530uXm6I5syMTR2hwCzLas+siiZKVg6VuI9rjDZ1aDfjrHtGaORV ms3p2pdioz1iePnB4h25jAf8C4DMPYV/K6oj838fV8IsUpA=
X-Google-Smtp-Source: ABdhPJx6xJuMHE1fshmfsRmgmAR3XzQluNBD+dymFsedMMhURa+GPjMerLZON7+FK0baZXHHOaC1UZjqTak9wkrZ9WY=
X-Received: by 2002:a5e:970a:: with SMTP id w10mr5348533ioj.114.1591825562791; Wed, 10 Jun 2020 14:46:02 -0700 (PDT)
MIME-Version: 1.0
References: <CALGR9obRjBSADN1KtKF6jvFVzNS1+JzaS0D0kCVKHKkd4sn+MQ@mail.gmail.com> <459C86F8-A989-4EF4-84DC-3568FF594F36@apple.com> <CANatvzwSpSHd7kZD-4tyMGkBJDdCBi6r_pLBvnaT8rrQy6SBHQ@mail.gmail.com> <CACMu3treK0m2mbpw9FebOjOcEed0bW-DbLbryHJH1DWAHoz+9g@mail.gmail.com> <CAJV+MGy2CytgPVEwEO3nDfpZ6h9+CCL-bODk=65cXexvS3N7Lw@mail.gmail.com> <CALGR9oYDApddLFzXv180TEXpmTaOpDCDNY41PxmbMJK7N4F4zQ@mail.gmail.com> <CAMWgRNaMZxph3zQv+O-SW7=PKBtDuGZNQ4+3X2geyXU545Vx9w@mail.gmail.com>
In-Reply-To: <CAMWgRNaMZxph3zQv+O-SW7=PKBtDuGZNQ4+3X2geyXU545Vx9w@mail.gmail.com>
From: Kinuko Yasuda <kinuko@chromium.org>
Date: Thu, 11 Jun 2020 06:45:51 +0900
Message-ID: <CAMWgRNaBAodWewpbi4cqFiMLWVd0SDnau7B4x0tjk+i=sMURpQ@mail.gmail.com>
To: Lucas Pardue <lucaspardue.24.7@gmail.com>
Cc: Patrick Meenan <patmeenan@gmail.com>, Bence Béky <bnc@chromium.org>, Kazuho Oku <kazuhooku@gmail.com>, Eric Kinnear <ekinnear@apple.com>, Yoav Weiss <yoav@yoav.ws>, Patrick Meenan <pmeenan@webpagetest.org>, HTTP Working Group <ietf-http-wg@w3.org>
Content-Type: multipart/alternative; boundary="00000000000037634105a7c1c529"
Received-SPF: pass client-ip=2607:f8b0:4864:20::d36; envelope-from=kinuko@google.com; helo=mail-io1-xd36.google.com
X-W3C-Hub-Spam-Status: No, score=-12.2
X-W3C-Hub-Spam-Report: BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.25, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, USER_IN_DEF_SPF_WL=-7.5, W3C_AA=-1, W3C_IRA=-1, W3C_WL=-1
X-W3C-Scan-Sig: titan.w3.org 1jj8Y2-0002Fi-8l b459c8a3a52f5dd1aba7c5bda7c97abc
X-Original-To: ietf-http-wg@w3.org
Subject: Re: Extensible Priorities and Reprioritization
Archived-At: <https://www.w3.org/mid/CAMWgRNaBAodWewpbi4cqFiMLWVd0SDnau7B4x0tjk+i=sMURpQ@mail.gmail.com>
Resent-From: ietf-http-wg@w3.org
X-Mailing-List: <ietf-http-wg@w3.org> archive/latest/37746
X-Loop: ietf-http-wg@w3.org
Resent-Sender: ietf-http-wg-request@w3.org
Precedence: list
List-Id: <ietf-http-wg.w3.org>
List-Help: <https://www.w3.org/Mail/>
List-Post: <mailto:ietf-http-wg@w3.org>
List-Unsubscribe: <mailto:ietf-http-wg-request@w3.org?subject=unsubscribe>
(Sorry, sent it too soon...) On Thu, Jun 11, 2020 at 6:12 AM Kinuko Yasuda <kinuko@chromium.org> wrote: > Hi all, > > Reg: reprioritization benefit I can share some recent data for Chrome. > For the two cases that are currently discussed I'm actually not fully sure > about its benefit. > > For the renderer-triggered image reprioritization cases: this is a bit > interesting one, we recently found two things: > - Delaying to start low-prio requests could often work better (partly > because of server-side handling) than re-prioritizing while inflight > - In-lab measurements (tested with top 10k real sites, both on Mobile and > Desktop) showed that removing in-flight re-prioritization doesn't impact > page load performance a lot > Let me stress though that testing this with servers that can properly handle reprioritization could change the landscape, and again this isn't really capturing how it affects long-lived request cases, or cases where tabs go foreground & background while loading, so for now I'm not very motivated to remove the reprioritization feature either. > I suspect this is maybe because server-side handling is not always perfect > and most of requests on the web are short-lived, and this may not be true > for the cases where long-running requests matter. I don't have data for > whether may impact background / foreground cases (e.g. Chrome tries to > lower priorities when tabs become background) > > For download cases, Chrome always starts a new download with a low > priority (even if it has started as a navigation), so reprioritization > doesn't happen. > > Kinuko > > > > > > > On Wed, Jun 10, 2020 at 1:21 AM Lucas Pardue <lucaspardue.24.7@gmail.com> > wrote: > >> On Tue, Jun 9, 2020 at 4:27 PM Patrick Meenan <patmeenan@gmail.com> >> wrote: >> >>> Eric's download example is a great one for exposing the risks that would >>> come for an implementation that supported prioritization but not >>> reprioritization. >>> >>> Take the trivial example of an anchor link that links to a download >>> (say, a 200MB installer of some kind): >>> - When the user clicks on the link, the browser assumes it is doing a >>> navigation and issues the request with the "HTML" priority (relatively >>> high, possibly non-incremental >>> - When the response starts coming back, it has the content-disposition >>> to download to a file. >>> - At this point, the 200MB download will block every other >>> lower-priority request on the same connection (or possibly navigation if it >>> is non-incremental) >>> - The user clicks on another page on the same site and gets nothing or a >>> broken experience until the 200MB download completes >>> >>> Without reprioritization the browser will effectively have to burn the >>> existing QUIC connection and issue any requests on a new connection (and >>> repeat for each new download). >>> >>> Implementing prioritization without reprioritization in this case is >>> worse than having no prioritization support at all. >>> >> >> Thanks Eric for presenting this case, and Patrick for breaking it down. >> That does seem like a pretty bad outcome. >> >> Is this a good candidate for a test case? IIUC correctly the problem >> might occur today with HTTP/2 depending on how exclusive priorities are >> used. I'm curious if browsers can share any more information about what >> they do already. How does Firefox manage such a resource with it's priority >> groups? >> >> Cheers >> Lucas >> >>
- Extensible Priorities and Reprioritization Lucas Pardue
- Re: Extensible Priorities and Reprioritization Yoav Weiss
- Re: Extensible Priorities and Reprioritization Lucas Pardue
- Re: Extensible Priorities and Reprioritization Patrick Meenan
- Re: Extensible Priorities and Reprioritization Lucas Pardue
- Re: Extensible Priorities and Reprioritization Yoav Weiss
- Re: Extensible Priorities and Reprioritization Eric Kinnear
- Re: Extensible Priorities and Reprioritization Kazuho Oku
- Re: Extensible Priorities and Reprioritization Martin Thomson
- Re: Extensible Priorities and Reprioritization Bence Béky
- Priority implementation complexity (was: Re: Exte… Lucas Pardue
- Re: Priority implementation complexity (was: Re: … Dmitri Tikhonov
- Re: Priority implementation complexity (was: Re: … Patrick Meenan
- Re: Extensible Priorities and Reprioritization Patrick Meenan
- Re: Extensible Priorities and Reprioritization Lucas Pardue
- Re: Priority implementation complexity (was: Re: … Lucas Pardue
- Re: Priority implementation complexity (was: Re: … Dmitri Tikhonov
- Re: Priority implementation complexity (was: Re: … Roy T. Fielding
- Re: Extensible Priorities and Reprioritization Kinuko Yasuda
- Re: Extensible Priorities and Reprioritization Kinuko Yasuda
- Re: Priority implementation complexity (was: Re: … Kazuho Oku
- Re: Priority implementation complexity (was: Re: … Yoav Weiss
- Re: Priority implementation complexity (was: Re: … Martin Thomson
- Re: Priority implementation complexity (was: Re: … Kazuho Oku
- Re: Priority implementation complexity (was: Re: … Stefan Eissing
- Re: Priority implementation complexity (was: Re: … Yoav Weiss
- Re: Priority implementation complexity (was: Re: … Stefan Eissing
- Re: Priority implementation complexity (was: Re: … Yoav Weiss
- Re: Priority implementation complexity (was: Re: … Stefan Eissing
- Re: Priority implementation complexity (was: Re: … Yoav Weiss
- Re: Priority implementation complexity (was: Re: … Patrick Meenan
- Re: Priority implementation complexity (was: Re: … Yoav Weiss
- Re: Priority implementation complexity (was: Re: … Patrick Meenan
- Re: Priority implementation complexity (was: Re: … Kazuho Oku
- Re: Priority implementation complexity (was: Re: … Yoav Weiss
- Re: Priority implementation complexity (was: Re: … Barry Pollard
- Re: Priority implementation complexity (was: Re: … Barry Pollard
- Re: Extensible Priorities and Reprioritization Kazuho Oku
- Re: Extensible Priorities and Reprioritization Yoav Weiss
- Re: Priority implementation complexity (was: Re: … Lucas Pardue
- Re: Priority implementation complexity (was: Re: … Tom Bergan
- Re: Priority implementation complexity (was: Re: … Lucas Pardue
- Re: Priority implementation complexity (was: Re: … Tom Bergan
- Re: Priority implementation complexity (was: Re: … Lucas Pardue
- Re: Extensible Priorities and Reprioritization Patrick Meenan
- Re: Extensible Priorities and Reprioritization Patrick Meenan
- Re: Extensible Priorities and Reprioritization Lucas Pardue
- Reprioritization - implementation intent Mark Nottingham
- Re: Reprioritization - implementation intent Eric Kinnear
- Nice to have guidance (was: Re: Reprioritization … Lucas Pardue
- Re: Nice to have guidance (was: Re: Reprioritizat… Eric Kinnear
- Re: Reprioritization - implementation intent Yoav Weiss
- Re: Reprioritization - implementation intent Yoav Weiss
- Re: Reprioritization - implementation intent Yoav Weiss