Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 7E7BCD8F for ; Wed, 9 Dec 2015 07:00:04 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-ig0-f172.google.com (mail-ig0-f172.google.com [209.85.213.172]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 5EB31126 for ; Wed, 9 Dec 2015 07:00:03 +0000 (UTC) Received: by igcph11 with SMTP id ph11so112256744igc.1 for ; Tue, 08 Dec 2015 23:00:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=friedenbach-org.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=wRamgxi2FYspUx8/lrh8SmH2Ddbaiy20deY5gPuaRKc=; b=DeN1Zsu6zsekvBdsZMHC0TwtjeCHBJ+p//iyswHYM0Anstqbx1PeAEGV0fw+VqgYkX T2TFeg3rvsFs2HYNW+obX0knDGUI+ROCYwSAD+T8kK/aUrzDGDzjM37vmEb/4yyWQ06c XX4TRKepTQkw5u/DKZ01uxfr2Cb7GvolyFvpylOy1sBlJ8x/3gjsC1proUn3cXMb/Cr8 wl6q5TV+4McLBphZYGwljzO3+PT342eJ1lNtAGbm0SBeWfU8hSMvd46XPrAepMq8aqMD p1iQzaB59AYhJ3KP7BBxe59hFldvk31H45JA6LXT+NVg1OFcJmuJVO9Iu7kOMWlD2d32 f6pQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type; bh=wRamgxi2FYspUx8/lrh8SmH2Ddbaiy20deY5gPuaRKc=; b=hxjaWQB35EYW+KsU9fLOKL4yeHasLzPf9UFXKgDzFpekxFru2jBvbpcl3ULsFxkV0O dHSO2lmI6opzc063qjhm/VSrQVk79tKw6M866lzevHgjgZGhZS9+wZHMEWibSUE3ShM3 FQrD9/GXuKD/XEvTn504SSnCxHDDWk07mdbKvb20MwiZYBDYuZMOt6FbQWaO2+6knR4r 6W0wwJnA1BYLPQDmowAoti0HAGWnTOjU6mo0VLlDKV6uBV8NB9D5f8epWXgGAx3OrfIU yzVEDN3zPF4DZ7MoZfV/YLtwqQZtTQUF0nDrCC0cBW8BIojwXXcK+Qw9KNQgWnPh/Kv5 jC9g== X-Gm-Message-State: ALoCoQljzL/T2l8Lc16s0R28MZ5h+Fp6lLMHFioHlDvx0WQglOwduchTErulsSEMFDj5s7nIpeRQSp9+HPwz1uIGx6OxhAhogw== X-Received: by 10.50.66.144 with SMTP id f16mr24269375igt.22.1449644402579; Tue, 08 Dec 2015 23:00:02 -0800 (PST) MIME-Version: 1.0 Received: by 10.107.133.217 with HTTP; Tue, 8 Dec 2015 22:59:43 -0800 (PST) X-Originating-IP: [202.83.241.113] In-Reply-To: References: <20151208110752.GA31180@amethyst.visucore.com> From: Mark Friedenbach Date: Wed, 9 Dec 2015 14:59:43 +0800 Message-ID: To: Gregory Maxwell Content-Type: multipart/alternative; boundary=047d7bdc9daeaab8e9052671a326 X-Spam-Status: No, score=-1.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HTML_MESSAGE, RCVD_IN_DNSWL_LOW, RCVD_IN_SORBS_WEB autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Cc: Bitcoin Dev Subject: Re: [bitcoin-dev] Capacity increases for the Bitcoin system. X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Development Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Dec 2015 07:00:04 -0000 --047d7bdc9daeaab8e9052671a326 Content-Type: text/plain; charset=UTF-8 Greg, if you have actual data showing that putting the commitment in the last transaction would be disruptive, and how disruptive, that would be appreciated. Of the mining hardware I have looked at, none of it cared at all what transactions other than the coinbase are. You need to provide a path to the coinbase for extranonce rolling, but the witness commitment wouldn't need to be updated. I'm sorry but it's not clear how this would be an incompatible upgrade, disruptive to anything other than the transaction selection code. Maybe I'm missing something? I'm not familiar with all the hardware or pooling setups out there. On Wed, Dec 9, 2015 at 2:29 PM, Gregory Maxwell via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > On Wed, Dec 9, 2015 at 4:44 AM, Ryan Butler wrote: > >>I agree, but nothing I have advocated creates significant technical > >>debt. It is also a bad engineering practice to combine functional > >>changes (especially ones with poorly understood system wide > >>consequences and low user autonomy) with structural tidying. > > > > I don't think I would classify placing things in consensus critical code > > when it doesn't need to be as "structural tidying". Gavin said "pile on" > > which you took as implying "a lot", he can correct me, but I believe he > > meant "add to". > > Nothing being discussed would move something from consensus critical > code to not consensus critical. > > What was being discussed was the location of the witness commitment; > which is consensus critical regardless of where it is placed. Should > it be placed in an available location which is compatible with the > existing network, or should the block hashing data structure > immediately be changed in an incompatible way to accommodate it in > order to satisfy an ascetic sense of purity and to make fraud proofs > somewhat smaller? > > I argue that the size difference in the fraud proofs is not > interesting, the disruption to the network in an incompatible upgrade > is interesting; and that if it really were desirable reorganization to > move the commitment point could be done as part of a separate change > that changes only the location of things (and/or other trivial > adjustments); and that proceeding int this fashion would minimize > disruption and risk... by making the incompatible changes that will > force network wide software updates be as small and as simple as > possible. > > >> (especially ones with poorly understood system wide consequences and low > >> user autonomy) > > > > This implies there you have no confidence in the unit tests and > functional > > testing around Bitcoin and should not be a reason to avoid refactoring. > > It's more a reason to increase testing so that you will have confidence > when > > you refactor. > > I am speaking from our engineering experience in a public, > world-wide, multi-vendor, multi-version, inter-operable, distributed > system which is constantly changing and in production contains private > code, unknown and assorted hardware, mixtures of versions, unreliable > networks, undisclosed usage patterns, and more sources of complex > behavior than can be counted-- including complex economic incentives > and malicious participants. > > Even if we knew the complete spectrum of possible states for the > system the combinatioric explosion makes complete testing infeasible. > > Though testing is essential one cannot "unit test" away all the risks > related to deploying a new behavior in the network. > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > --047d7bdc9daeaab8e9052671a326 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Greg, if you have actual data showing that putting th= e commitment in the last transaction would be disruptive, and how disruptiv= e, that would be appreciated. Of the mining hardware I have looked at, none= of it cared at all what transactions other than the coinbase are. You need= to provide a path to the coinbase for extranonce rolling, but the witness = commitment wouldn't need to be updated.

I'm sorry but = it's not clear how this would be an incompatible upgrade, disruptive to= anything other than the transaction selection code. Maybe I'm missing = something? I'm not familiar with all the hardware or pooling setups out= there.

= On Wed, Dec 9, 2015 at 2:29 PM, Gregory Maxwell via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
On Wed, Dec 9, 2015 at 4:4= 4 AM, Ryan Butler <rryananizer@= gmail.com> wrote:
>>I agree, but nothing I have advocated creates significant technical=
>>debt. It is also a bad engineering practice to combine functional >>changes (especially ones with poorly understood system wide
>>consequences and low user autonomy) with structural tidying.
>
> I don't think I would classify placing things in consensus critica= l code
> when it doesn't need to be as "structural tidying".=C2= =A0 Gavin said "pile on"
> which you took as implying "a lot", he can correct me, but I= believe he
> meant "add to".

Nothing being discussed would move something from consensus critical=
code to not consensus critical.

What was being discussed was the location of the witness commitment;
which is consensus critical regardless of where it is placed. Should
it be placed in an available location which is compatible with the
existing network, or should the block hashing data structure
immediately be changed in an incompatible way to accommodate it in
order to satisfy an ascetic sense of purity and to make fraud proofs
somewhat smaller?

I argue that the size difference in the fraud proofs is not
interesting, the disruption to the network in an incompatible upgrade
is interesting; and that if it really were desirable reorganization to
move the commitment point could be done as part of a separate change
that changes only the location of things (and/or other trivial
adjustments); and that proceeding int this fashion would minimize
disruption and risk... by making the incompatible changes that will
force network wide software updates be as small and as simple as
possible.

>> (especially ones with poorly understood system wide consequences a= nd low
>> user autonomy)
>
> This implies there you have no confidence in the unit tests and functi= onal
> testing around Bitcoin and should not be a reason to avoid refactoring= .
> It's more a reason to increase testing so that you will have confi= dence when
> you refactor.

I am speaking from our engineering experience in a=C2=A0 public,
world-wide, multi-vendor, multi-version, inter-operable, distributed
system which is constantly changing and in production contains private
code, unknown and assorted hardware, mixtures of versions, unreliable
networks, undisclosed usage patterns, and more sources of complex
behavior than can be counted-- including complex economic incentives
and malicious participants.

Even if we knew the complete spectrum of possible states for the
system the combinatioric explosion makes complete testing infeasible.

Though testing is essential one cannot "unit test" away all the r= isks
related to deploying a new behavior in the network.
___________________________________= ____________
bitcoin-dev mailing list
bitcoin-dev@lists.= linuxfoundation.org
https://lists.linuxfoundation.org/mail= man/listinfo/bitcoin-dev

--047d7bdc9daeaab8e9052671a326--