1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
Return-Path: <pavel.moravec@braiins.cz>
Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org
[172.17.192.35])
by mail.linuxfoundation.org (Postfix) with ESMTPS id 56914899
for <bitcoin-dev@lists.linuxfoundation.org>;
Sat, 8 Apr 2017 16:38:10 +0000 (UTC)
X-Greylist: whitelisted by SQLgrey-1.7.6
Received: from mail-wm0-f44.google.com (mail-wm0-f44.google.com [74.125.82.44])
by smtp1.linuxfoundation.org (Postfix) with ESMTPS id E6553FF
for <bitcoin-dev@lists.linuxfoundation.org>;
Sat, 8 Apr 2017 16:38:05 +0000 (UTC)
Received: by mail-wm0-f44.google.com with SMTP id w64so11677552wma.0
for <bitcoin-dev@lists.linuxfoundation.org>;
Sat, 08 Apr 2017 09:38:05 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=braiins-cz.20150623.gappssmtp.com; s=20150623;
h=mime-version:in-reply-to:references:from:date:message-id:subject:to
:cc; bh=kesfdhjPqW+FZAig7YApCd+QX/PvggKnr7bG28ZuWs4=;
b=0qw57c9YO0RSF3+w3cEwEuMsfYwDttqXILGX80wcPhRJ2hkhjZoPkikRdOn2s0ShQU
J72UGBWtE+YQuIbWYpB+gIMqZOiH2Z8Bo8CVhAcN3Rkhj5dNDrHifvDoBzs5usKNnqbE
5S4emevqlfADLuRvij+lQv0sarK2yuCgCwuj+kBW6X97aPUW+3l0DsDc1/4H6jiKsOht
Dfmm3ZSyMBvtNXNwbU9pxcvAnoXVgY17/HI0NTmCqjIk0bMmlB1FA8sK7YwomrHC5QUF
2IzF+ZKEABfhiY/UIxNj0V5/Hg4SFuAZpn1pTR8idJIO2omKrv4u+Mhcnw5OtftyH6Hp
5DzQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=1e100.net; s=20161025;
h=x-gm-message-state:mime-version:in-reply-to:references:from:date
:message-id:subject:to:cc;
bh=kesfdhjPqW+FZAig7YApCd+QX/PvggKnr7bG28ZuWs4=;
b=gvQ+wsiqeFpgITJZ9X+SwJjSGrMGCEnuRyV8h3W6eNSH5nId6F/V2tI6j2nx8/clu5
BMuVOVr61V6ttpsj3EAW7wZqVYUlTHyzi2XU4XPvFTHItRMmIrKgpIj5+iJhbyCNNEMO
lF/L+eKckVqtp5DnI2G5nA6dLhL7gD+9Y4du6TnmWDekxuBgjpokZFoUDcVP8qXjXZ9I
AQRFHQH8NrXF+4Mc5TyNcNXhKrSjG/yEgKV0bNC7MJPd89ioVzrlXU50ES/UGPgXwBaD
dS+V9Zze4LjIRJcEVOFZCXwg45kAi1hX5zHe34IQR5qRnqaFyXX3k+ZkzLKGU63WVUeV
VZlg==
X-Gm-Message-State: AN3rC/6G/mX/jFSju5cW25cIP/BpCW2nN63u4CXygx6ejm9aoTOd0kpdSGAfBHdYcCxvlRx6U5QE15l2NkCvdQ==
X-Received: by 10.28.178.17 with SMTP id b17mr3598518wmf.23.1491669484523;
Sat, 08 Apr 2017 09:38:04 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.28.223.138 with HTTP; Sat, 8 Apr 2017 09:38:03 -0700 (PDT)
X-Originating-IP: [46.135.49.9]
In-Reply-To: <CAJR7vkrn-oFium3wFgcOdqNPuYq+rW2DqyOnkDaCTHabO0y3Xg@mail.gmail.com>
References: <CAJR7vkpRhNsQsem-nFkeubX04xx1y7aHwCENfg0d1266oOsXMw@mail.gmail.com>
<Cwhn7YzwaDUZtOygDAgrU1UXjRPG-EiH3Fyz2c95gqOpNnNbiYL1NvhS28yK5wLJCnIqDaBrM6c574dY-O6_-bRjLIFmDe2NCxIuyV1w2dw=@protonmail.com>
<CAJR7vkoq8Y_-fbdxN=--gF5wrGByr5oODc4FkTaCEvDSuP0whQ@mail.gmail.com>
<CACDYSUROutAMV7C8pUXz0PMvH5awkw-XUtce7BxTtZMD_yUm5A@mail.gmail.com>
<CAJR7vkrn-oFium3wFgcOdqNPuYq+rW2DqyOnkDaCTHabO0y3Xg@mail.gmail.com>
From: Pavel Moravec <pavel.moravec@braiins.cz>
Date: Sat, 8 Apr 2017 18:38:03 +0200
Message-ID: <CACDYSUS29qoaNML8XmRz6xDSZsiHe2kYsEFun-kBLaups-OiJg@mail.gmail.com>
To: Jimmy Song <jaejoon@gmail.com>
Content-Type: text/plain; charset=UTF-8
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,
DKIM_VALID,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
smtp1.linux-foundation.org
X-Mailman-Approved-At: Sat, 08 Apr 2017 16:44:20 +0000
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] A Small Modification to Segwit
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/>
List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org>
List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe>
X-List-Received-Date: Sat, 08 Apr 2017 16:38:10 -0000
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
|
