Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 3333911A0 for ; Thu, 3 Sep 2015 14:40:39 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-wi0-f173.google.com (mail-wi0-f173.google.com [209.85.212.173]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 5B61E10B for ; Thu, 3 Sep 2015 14:40:38 +0000 (UTC) Received: by wicge5 with SMTP id ge5so76395073wic.0 for ; Thu, 03 Sep 2015 07:40:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=RTnBX1Lr/s7/OX3UHInyuQ2ZxP/8V5zGb4lgIJEZjBg=; b=Grb9ELNKmn4ruSSYfngWjnmVkH+mTEMdNG6RrcFc8mfbkyeC54zJUwxopRC35N6T5K 3/7vj2eFbtr3NJ3iSOqj/uzhDq+dFFgav+OLSAqJfmAiXi2tn2djIJQHtZLNNfv7Y3Tv P9qLVwy3XoxrC+YVVNK2mq9IRGvueq7IKYiItmDZjqX27xG+fYCy0knP/o80erq8s3rM c2fGJdmqjqevZKZ3vrBe8jfV835Bw1Vcx+w1qbKu5owSYbCaf577Zt8JID3AXZ0Dtmmq d3hTBxFmej2uP2iPuLRZSJIROqX/2xTnZq4vPtxNM715aOWaVmDbEgSYqRFmfzMLz/ft XOuA== MIME-Version: 1.0 X-Received: by 10.194.176.201 with SMTP id ck9mr51027699wjc.108.1441291237173; Thu, 03 Sep 2015 07:40:37 -0700 (PDT) Received: by 10.28.15.11 with HTTP; Thu, 3 Sep 2015 07:40:37 -0700 (PDT) In-Reply-To: References: Date: Thu, 3 Sep 2015 10:40:37 -0400 Message-ID: From: Jeff Garzik To: Gregory Maxwell Content-Type: multipart/alternative; boundary=089e013d1eb435aec8051ed8c49c X-Spam-Status: No, score=-2.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Cc: Bitcoin development mailing list Subject: Re: [bitcoin-dev] block size - pay with difficulty 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: Thu, 03 Sep 2015 14:40:39 -0000 --089e013d1eb435aec8051ed8c49c Content-Type: text/plain; charset=UTF-8 Expanding on pay-with-diff and volatility (closing comment), Users and miners will have significant difficulty creating and/or predicting a stable block size (and fee environment) with pay-with-diff across the months. The ability of businesses to plan is low. Chaos and unpredictability are bad in general for markets and systems. Thus the binary conclusion of "not get used" or "volatility" On Thu, Sep 3, 2015 at 10:31 AM, Jeff Garzik wrote: > It's written as 'a' and/or 'b'. If you don't have idle hashpower, then > paying with difficulty requires some amount of collusion ('a') > > Any miner paying with a higher difficulty either needs idle hashpower, or > self-increase their own difficulty at the possible *opportunity cost* of > losing an entire block's income to another miner who doesn't care about > changing the block size. The potential loss does not economically > compensate for size increase gains in most cases, when you consider the > variability of blocks (they come in bursts and pauses) and the fee income > that would be associated. > > Miners have more to lose paying with diff than they gain -- unless the > entire network colludes out-of-band with ~90% certainty, by collectively > agreeing to increase the block period by collectively agreeing with > pay-with-diff until the globally desired block size is reached. At that > level of collusion, we can create far more simple schemes to increase block > size. > > Pay-with-diff will either not get used, or lead to radical short term > block size (and thus fee) volatility. It is complex & difficult for all > players to reason, and a Rational game theory choice can be to avoid > paying-for-diff even when the network desperately needs an upgrade. > > > > > > > On Thu, Sep 3, 2015 at 2:57 AM, Gregory Maxwell > wrote: > >> On Thu, Sep 3, 2015 at 4:05 AM, Jeff Garzik via bitcoin-dev >> wrote: >> > (b) requiring miners to have idle >> > hashpower on hand to change block size are both unrealistic and >> potentially >> >> I really cannot figure out how you could characterize pay with >> difficty has in any way involving idle hashpower. >> >> Can you walk me through this? >> > > --089e013d1eb435aec8051ed8c49c Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Expanding on pay-with-diff and volatility (closing comment= ),

Users and miners will have significant difficulty cre= ating and/or predicting a stable block size (and fee environment) with pay-= with-diff across the months.=C2=A0 The ability of businesses to plan is low= .=C2=A0 Chaos and unpredictability are bad in general for markets and syste= ms.=C2=A0 Thus the binary conclusion of "not get used" or "v= olatility"




=


On Thu, Sep 3, 2015 at 10:31 AM, Jeff Garzik &l= t;jgarzik@gmail.com<= /a>> wrote:
It= 's written as 'a' and/or 'b'.=C2=A0 If you don't ha= ve idle hashpower, then paying with difficulty requires some amount of coll= usion ('a') =C2=A0

Any miner paying with a higher diff= iculty either needs idle hashpower, or self-increase their own difficulty a= t the possible opportunity cost of losing an entire block's inco= me to another miner who doesn't care about changing the block size.=C2= =A0 The potential loss does not economically compensate for size increase g= ains in most cases, when you consider the variability of blocks (they come = in bursts and pauses) and the fee income that would be associated.

Miners have more to lose paying with diff than they gain -= - unless the entire network colludes out-of-band with ~90% certainty, by co= llectively agreeing to increase the block period by collectively agreeing w= ith pay-with-diff until the globally desired block size is reached.=C2=A0 A= t that level of collusion, we can create far more simple schemes to increas= e block size.

Pay-with-diff will either not get us= ed, or lead to radical short term block size (and thus fee) volatility.=C2= =A0 It is complex & difficult for all players to reason, and a Rational= game theory choice can be to avoid paying-for-diff even when the network d= esperately needs an upgrade.






On Thu= , Sep 3, 2015 at 2:57 AM, Gregory Maxwell <gmaxwell@gmail.com> wrote:
On Thu, Sep 3, 2015 at 4= :05 AM, Jeff Garzik via bitcoin-dev
<bitcoin-dev@lists.linuxfoundation.org> wrote:
> (b) requiring miners to have idle
> hashpower on hand to change block size are both unrealistic and potent= ially

I really cannot figure out how you could characterize pay with
difficty has in any way involving idle hashpower.

Can you walk me through this?


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