From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-2.8 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD shortcircuit=no autolearn=no autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 1642B1F404 for ; Mon, 5 Mar 2018 21:36:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932630AbeCEVg4 (ORCPT ); Mon, 5 Mar 2018 16:36:56 -0500 Received: from mail-pl0-f65.google.com ([209.85.160.65]:42435 "EHLO mail-pl0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932450AbeCEVgw (ORCPT ); Mon, 5 Mar 2018 16:36:52 -0500 Received: by mail-pl0-f65.google.com with SMTP id 93-v6so10508911plc.9 for ; Mon, 05 Mar 2018 13:36:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=YBh0YzUgu01mCBde6X+NdZrF23qaoJISCgB7ya6ZFrc=; b=OSizpFCsFM0ZXoFZ132QGP4jCkcp4/KMcNlP9BalwYpyFZEcvMVt2pwKqEfSPmicui 6PCmIzrG7CFNlQvuf0uOSC9T4terVpZrzd/0ik7vctY4NPoYQcRJwQSgYrU7LYrbfRVM gA+UOXMMBMnANNVbjab8bsFICyAR8Wrpb1SPDO04kEakDImE5Z/Ea9r/BrUZ64RrhSUL VDhSTUfPJGKxggjfLRFNXDTwnqlZcSmagTBOZFOGEHimBknL+tfB1rmzQpTNCRpGtUOu oljKNN1cNxc0KNVpA9lbI11Ua6H4QHvaPT+7lC7EYlOTHMoPAvEgg4igdShA/W+Rbq2H wk1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=YBh0YzUgu01mCBde6X+NdZrF23qaoJISCgB7ya6ZFrc=; b=uTq+7OdH7ziNWIEJTvXnJ6QyMOmj6VEiUWqDEZcHV9ZwCnMaV5fnXrPFHxS8JRoLVv sggA03FvvlQEXLgTYH7Wj930RGhRoAt7Dl84B5aTxAiZ1K05K0KYKMsIyHnmzsgOGDmX QhfcnsyKtmHv/MM5dC1Mg5PpFVL80LxDa3QnptpZSUgGcnIaTVOoaLpf8SB5jU/Re7Gn m2SHbxR9TBbBZKydRWkkqT3/SxtQWBZXjTjfdT6JOisjefb/hEqgGyWNri0NI9ED6okS bsPMCBUteOiGKJlZSGSG2nm+depIsUDBF4rSD1WdYa4W16RrAxZGTVD2+fek8bF8kNWX +lpw== X-Gm-Message-State: APf1xPArv3MLqIQTG37gROVvQK4n9VKrDxxDPNTIX26/aK02gysjCpv4 BKZH9/kjMedHsdjrkQJmsbw= X-Google-Smtp-Source: AG47ELtRtOmQqtdkzhpdtvIBF8wbUPeyfxyccDTosA4/gQqU6tCBg9ijDRBGD1HN78QkZ7H/FTm3Og== X-Received: by 2002:a17:902:b691:: with SMTP id c17-v6mr14349426pls.308.1520285811941; Mon, 05 Mar 2018 13:36:51 -0800 (PST) Received: from aiede.svl.corp.google.com ([2620:0:100e:422:4187:1d6c:d3d6:9ce6]) by smtp.gmail.com with ESMTPSA id g13sm23893073pfi.134.2018.03.05.13.36.50 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 05 Mar 2018 13:36:51 -0800 (PST) Date: Mon, 5 Mar 2018 13:36:49 -0800 From: Jonathan Nieder To: Jeff King Cc: Brandon Williams , git@vger.kernel.org, sbeller@google.com, gitster@pobox.com, stolee@gmail.com, git@jeffhostetler.com, pclouds@gmail.com Subject: Re: [PATCH v3 12/35] serve: introduce git-serve Message-ID: <20180305213649.GF28067@aiede.svl.corp.google.com> References: <20180125235838.138135-1-bmwill@google.com> <20180207011312.189834-1-bmwill@google.com> <20180207011312.189834-13-bmwill@google.com> <20180222093327.GA12442@sigill.intra.peff.net> <20180223214557.GF234838@google.com> <20180303043338.GC27689@sigill.intra.peff.net> <20180305184321.GC72475@google.com> <20180305205254.GC5953@sigill.intra.peff.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180305205254.GC5953@sigill.intra.peff.net> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Hi, Jeff King wrote: > I agree that would be a lot more pleasant for adding protocol features. > But I just worry that the stateful protocols get a lot less efficient. > I'm having trouble coming up with an easy reproduction, but my > recollection is that http has some nasty corner cases, because each > round of "have" lines sent to the server has to summarize the previous > conversation. So you can get a case where the client's requests keep > getting bigger and bigger during the negotiation (and eventually getting > large enough to cause problems). That's not so much a corner case as just how negotiation works over http. We want to do better (e.g. see [1]) but that's a bigger change than the initial protocol v2. As Brandon explained it to me, we really do want to use stateless-rpc semantics by default, since that's just better for maintainability. Instead of having two protocols, one that is sane and one that struggles to hoist that into stateless-rpc, there would be one stateless baseline plus capabilities to make use of state. For example, it would be nice to have a capability to remember negotiation state between rounds, to get around exactly the problem you're describing when using a stateful protocol. Stateless backends would just not advertise such a capability. But doing that without [1] still sort of feels like a cop-out. If we can get a reasonable baseline using ideas like [1] and then have a capability to keep server-side state as icing on the cake instead of having a negotiation process that only really makes sense when you have server-side state, then that would be even better. > If anything, I wish we could push the http protocol in a more stateful > direction with something like websockets. But I suspect that's an > unrealistic dream, just because not everybody's http setup (proxies, > etc) will be able to handle that. Agreed. I think we have to continue to deal with stateless-rpc semantics, at least for the near future. Jonathan [1] https://public-inbox.org/git/20180227054638.GB65699@aiede.svl.corp.google.com/