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From: Pavel Moravec <pavel.moravec@braiins.cz>
To: Jimmy Song <jaejoon@gmail.com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] A Small Modification to Segwit
Date: Sat, 8 Apr 2017 18:38:03 +0200	[thread overview]
Message-ID: <CACDYSUS29qoaNML8XmRz6xDSZsiHe2kYsEFun-kBLaups-OiJg@mail.gmail.com> (raw)
In-Reply-To: <CAJR7vkrn-oFium3wFgcOdqNPuYq+rW2DqyOnkDaCTHabO0y3Xg@mail.gmail.com>

Jimmy,

>> Until all miners update (firmware or hardware), the change encourages
>> large difference in mining efficiency. And IMO it gives another
>> advantage to large mining operations in general.
>
> Certainly, there would have to be changes for stratum, pool software, etc.
> But the monetary incentives align to all the changes needed.

I agree. I only wanted to make clear, that the impact would be
significant. Lot of parties would be involved with nonequivalent
starting positions.

> Remember, overt ASICBoost can get something like a 12.5% efficiency boost
> from toggling a single bit in the version (equivalent to 2 colliding work
> items), 18.5% from 2 bits (equivalent to 4 colliding work items), 23.4% from
> 4 bits (see https://arxiv.org/ftp/arxiv/papers/1604/1604.00575.pdf). In lieu
> of an explicit allowance of overt ASICBoost, the monetary incentives lead to
> odd BIP9 signaling, especially if 4 or more proposals signal at once. There
> really isn't a practical way to block overt ASICBoost without forcing the
> version bits to be some value.

You can e.g. place the version number into a coinbase, similarly to
block height. Then, it is the same (number of operations) as modifying
the coinbase directly.

A cost of version in coinbase is 4B per block, sure, but it allows to
save all bits for "more useful" purposes. Either for BIP9 signalling
or other future purposes I cannot see now. And it removes an incentive
to mess with version bits.

Mining empty blocks and finding collisions by toggling bits there can
be prevented as well.

> In other words, the question isn't about allowing/disallowing ASICBoost at
> this point. The question is whether we want ASICBoost open or hidden.

I think the ASICBoost can and should be prevented completely.


Pavel


  reply	other threads:[~2017-04-08 16:38 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-07 20:06 [bitcoin-dev] A Small Modification to Segwit Jimmy Song
2017-04-08  0:05 ` Jimmy Song
2017-04-08 14:59   ` Luke Dashjr
2017-04-08 15:17     ` Jimmy Song
2017-04-08 16:05       ` Luke Dashjr
2017-04-08 16:16         ` Jimmy Song
2017-04-08 16:19   ` Timo Hanke
2017-04-08  1:48 ` praxeology_guy
2017-04-08  2:46   ` Jimmy Song
2017-04-08  8:33     ` Pavel Moravec
2017-04-08 14:35       ` Jimmy Song
2017-04-08 16:38         ` Pavel Moravec [this message]
2017-04-08 22:19           ` Jimmy Song
2017-04-08 18:15         ` praxeology_guy
2017-04-08 18:51           ` Eric Voskuil
2017-04-08 20:38             ` praxeology_guy
2017-04-09 11:46           ` Jorge Timón
2017-04-08 16:27     ` Jorge Timón
2017-04-08 17:22       ` Jorge Timón
2017-04-08 22:26         ` Jimmy Song
2017-04-09 11:48           ` Jorge Timón
2017-04-09 14:01             ` Jimmy Song
     [not found]               ` <CABm2gDqfsBREj2x5Uz9hxwt-Y6m=KHd2-hRw4gV0CbO+-8B0dg@mail.gmail.com>
2017-04-10  9:16                 ` Jorge Timón
2017-04-09 18:44   ` Erik Aronesty
2017-04-09 21:16     ` Jared Lee Richardson
2017-04-09 23:51       ` David Vorick
2017-04-10  0:20         ` Erik Aronesty
2017-04-10  1:45           ` Thomas Daede
2017-04-10 14:34     ` Bram Cohen
2017-04-10 14:46     ` Bram Cohen
2017-04-10 15:25     ` g
2017-04-10 18:17       ` Erik Aronesty
2017-04-11  2:39         ` g
2017-04-11 18:39           ` Staf Verhaegen
2017-04-11  9:31       ` Sancho Panza
2017-04-11 13:00         ` Jorge Timón
2017-04-11  7:59 ` Tom Zander
2017-04-11 13:25   ` Sancho Panza
2017-04-11 14:40     ` Jimmy Song
2017-04-11 21:25       ` Jorge Timón
2017-04-11 23:42         ` Jimmy Song

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