From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Z5hru-0005h7-L7 for bitcoin-development@lists.sourceforge.net; Thu, 18 Jun 2015 22:01:06 +0000 X-ACL-Warn: Received: from mail-pd0-f174.google.com ([209.85.192.174]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1Z5hrr-0007NZ-KO for bitcoin-development@lists.sourceforge.net; Thu, 18 Jun 2015 22:01:06 +0000 Received: by pdjn11 with SMTP id n11so75357732pdj.0 for ; Thu, 18 Jun 2015 15:00:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:user-agent:mime-version:to :cc:subject:references:in-reply-to:content-type :content-transfer-encoding; bh=w+DWrcCfoY76r4PEJi1035yOwob7Gu7JIridxT6Gaio=; b=MunTNS4hg61Anc4PGix1OaPzH+zPikVt9SQf9IJquAlIF1gR8ubqqR7j8843+X/B+y SF9YAU201C8rZFwDLbTuoNo52LFTk/Z2n2RN4glJFeYeSC83MmzlDQ0ISActahWdXj48 rV8DUgqp4XMrkS9fnKKnLQbMuMGBoGBgMIVrUTo68nm1I81NPameZOzcioxCWA7OaykH O2ZIq0+dVoH9c+RV4Fjt5FceuoG7FZYYYyBLwC6P8sqpzihsPeTAykq3SuwJoahvpIU/ gP0NAsM4ZDKV7hpF3XeKUyCCpVzjNkG4lFRA/6xLPRkObiPx37ED3ANqW4Z9aR1mi0ZY ih5A== X-Gm-Message-State: ALoCoQm92nB4FWDMofKa8O1DjMQEOxmzUH5NJI7KNir3pMIXiBZAjty/eC08esEGKrnh6sJQ7p4A X-Received: by 10.68.87.35 with SMTP id u3mr25029378pbz.127.1434664857839; Thu, 18 Jun 2015 15:00:57 -0700 (PDT) Received: from [10.100.1.239] ([204.58.254.99]) by mx.google.com with ESMTPSA id qa1sm9087370pab.0.2015.06.18.15.00.55 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 18 Jun 2015 15:00:56 -0700 (PDT) Message-ID: <55833F87.3090408@thinlink.com> Date: Thu, 18 Jun 2015 15:00:39 -0700 From: Tom Harding User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Pieter Wuille References: <557DBDCC.5040106@student.ethz.ch> In-Reply-To: <557DBDCC.5040106@student.ethz.ch> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: 0.6 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. 0.6 RCVD_IN_SORBS_WEB RBL: SORBS: sender is an abusable web server [204.58.254.99 listed in dnsbl.sorbs.net] X-Headers-End: 1Z5hrr-0007NZ-KO Cc: bitcoin-development@lists.sourceforge.net Subject: Re: [Bitcoin-development] Mining centralization pressure from non-uniform propagation speed X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Jun 2015 22:01:06 -0000 On 06/12/2015 06:51 PM, Pieter Wuille wrote: >> However, it does very clearly show the effects of >> larger blocks on centralization pressure of the system. On 6/14/2015 10:45 AM, Jonas Nick wrote: > This means that your scenario is not the result of a cartel but the result of a long-term network partition. > Pieter, to Jonas' point, in your scenario the big miners are all part of the majority partition, so "centralization pressure" (pressure to merge with a big miner) cannot be separated from "pressure to be connected to the majority partition". I ran your simulation with a large (20%) miner in a 20% minority partition, and 16 small (5%) miners in a majority 80% partition, well connected. The starting point was your recent update, which had a more realistic "slow link" speed of 100 Mbit/s (making all of the effects smaller). To summarize the results across both your run and mine: ** Making small blocks when others are making big ones -> BAD ** As above, and fees are enormous -> VERY BAD ** Being separated by a slow link from majority hash power -> BAD ** Being a small miner with blocksize=20MB -> *NOT BAD* Configuration: * Miner group 0: 20.000000% hashrate, blocksize 20000000.000000 * Miner group 1: 80.000000% hashrate, blocksize 1000000.000000 * Expected average block size: 4800000.000000 * Average fee per block: 0.250000 * Fee per byte: 0.0000000521 Result: * Miner group 0: 20.404704% income (factor 1.020235 with hashrate) * Miner group 1: 79.595296% income (factor 0.994941 with hashrate) Configuration: * Miner group 0: 20.000000% hashrate, blocksize 20000000.000000 * Miner group 1: 80.000000% hashrate, blocksize 20000000.000000 * Expected average block size: 20000000.000000 * Average fee per block: 0.250000 * Fee per byte: 0.0000000125 Result: * Miner group 0: 19.864232% income (factor 0.993212 with hashrate) * Miner group 1: 80.135768% income (factor 1.001697 with hashrate) Configuration: * Miner group 0: 20.000000% hashrate, blocksize 20000000.000000 * Miner group 1: 80.000000% hashrate, blocksize 1000000.000000 * Expected average block size: 4800000.000000 * Average fee per block: 25.000000 * Fee per byte: 0.0000052083 Result: * Miner group 0: 51.316895% income (factor 2.565845 with hashrate) * Miner group 1: 48.683105% income (factor 0.608539 with hashrate) Configuration: * Miner group 0: 20.000000% hashrate, blocksize 20000000.000000 * Miner group 1: 80.000000% hashrate, blocksize 20000000.000000 * Expected average block size: 20000000.000000 * Average fee per block: 25.000000 * Fee per byte: 0.0000012500 Result: * Miner group 0: 19.865943% income (factor 0.993297 with hashrate) * Miner group 1: 80.134057% income (factor 1.001676 with hashrate)