Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 74782CC0 for ; Thu, 3 Mar 2016 18:27:36 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-ig0-f175.google.com (mail-ig0-f175.google.com [209.85.213.175]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id C64D915E for ; Thu, 3 Mar 2016 18:27:35 +0000 (UTC) Received: by mail-ig0-f175.google.com with SMTP id z8so1163025ige.0 for ; Thu, 03 Mar 2016 10:27:35 -0800 (PST) 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; bh=90YtnWB3Sj6+rME1cDx2Saca+zJl/xp9aw7OuK/sWCo=; b=WYWyOHPu+QoLa5aArcQ7CYehCo+WWz8+9vCIq7hhJqHwzB1PhwyKxG35BRZAeCmMGe ccoRt2SunAMBRh+vt2mJ9eZjn4udE23eLa5vMtGyliU/Rh8x+aLkdLKVzBFLRdyxyi0x gEDpXJQXX/I6BI6t3wrAE51TAvy9H0MzII8oZX1oK6B+8FDUak0ghbe9S9AAA/FzNkEt e4AYB/malNiSOYhlK9NEK4ut+KYfi3bEh18d2k/lD+Ewc0doEXPgCXBusxhh2hYOOesE P9t0qPdee5V8ED9Y8kXZYCKyTZ0zRDNz9pAtUc8+jAphvy3ij5Bk9jJ+e/4N+7fibcJe OvPg== 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:date :message-id:subject:from:to:cc; bh=90YtnWB3Sj6+rME1cDx2Saca+zJl/xp9aw7OuK/sWCo=; b=YdB4s4ZHuSM8Irr7EUpifg4n6uxZlw/343h+XRk5aWt2ce3sk9e8l9Z9DZqVjeo9n9 dAwz1EL7NeZxQVIElrL1VRa7S+YCoMZEF3eadmA06qTjB5J0NjEvoY8+ywTDP5QF2+41 s8FgTa44IQIP+/pGBqnfBvS64wS4xXlzRw88+TZNjYixhGQjZz/K/l30VQzLsqyAaEnn MZEyQsIdH7I6oLScd7dD3NrcjU+4AfjrrVViJpVjuUBD/IP2A4tRcMEScm3PrRIFp6s5 7s982EfELkarQj2X/osQHczwEZy88oRlvE6/wYJKVH5ZJRW8IAdfZLz/Zgp/FrGi8Vst adfw== X-Gm-Message-State: AD7BkJKBw/GGykn7IOZUsk5MzwW0kQ32RD9S3eGag37nshDYrx0cu22zsL+4QW+iXRHRb7aSmUwV3z3052UuiA== MIME-Version: 1.0 X-Received: by 10.50.83.73 with SMTP id o9mr528210igy.90.1457029655180; Thu, 03 Mar 2016 10:27:35 -0800 (PST) Received: by 10.64.71.73 with HTTP; Thu, 3 Mar 2016 10:27:35 -0800 (PST) In-Reply-To: <201603021456.15820.luke@dashjr.org> References: <201603021456.15820.luke@dashjr.org> Date: Thu, 3 Mar 2016 10:27:35 -0800 Message-ID: From: Corey Haddad To: Luke Dashjr Content-Type: multipart/alternative; boundary=089e0116076c06418c052d292736 X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_ENVFROM_END_DIGIT,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 X-Mailman-Approved-At: Thu, 03 Mar 2016 21:00:21 +0000 Cc: Bitcoin Dev Subject: Re: [bitcoin-dev] Hardfork to fix difficulty drop algorithm 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 Mar 2016 18:27:36 -0000 --089e0116076c06418c052d292736 Content-Type: text/plain; charset=UTF-8 Since the root cause of what you are trying to address is the reward having, I'd suggest considering an adjustment to the having schedule. Instead of their being a large supply shock every four years, perhaps the reward could drop every 52,500 blocks (yearly), or even at each difficulty adjustment, in such a way that the inflation curve is smoothed out. The exponential decay rate would be preserved, so overall economic philosophy would be preserved. I'm guessing hesitance to this approach would lie in a reluctance to tinker with Bitcoin's 'economic contract', and slippery slope concerns about might be the next change (21M?). However, I think it could actually increase confidence in the system if the community is able to demonstrate a good process for making such decisions, and show that we can separate the meaningful underlying principles, such as the coin limit and overall inflation rate, from what is more akin to an implementation detail, as I consider the large-step reward reduction to be. I'm not too worried about the impact of the having as is, but adjusting the economic parameter would be a safer and simpler way to address the concerns than to tinker with the difficulty targeting mechanism, which is at the heart of Bitcoin's security On Wed, Mar 2, 2016 at 6:56 AM, Luke Dashjr via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > We are coming up on the subsidy halving this July, and there have been some > concerns raised that a non-trivial number of miners could potentially drop > off > the network. This would result in a significantly longer block interval, > which > also means a higher per-block transaction volume, which could cause the > block > size limit to legitimately be hit much sooner than expected. Furthermore, > due > to difficulty adjustment being measured exclusively in blocks, the time > until > it adjusts to compensate would be prolonged. > > For example, if 50% of miners dropped off the network, blocks would be > every > 20 minutes on average and contain double the transactions they presently > do. > Even double would be approximately 850-900k, which potentially bumps up > against the hard limit when empty blocks are taken into consideration. This > situation would continue for a full month if no changes are made. If more > miners drop off the network, most of this becomes linearly worse, but due > to > hitting the block size limit, the backlog would grow indefinitely until the > adjustment occurs. > > To alleviate this risk, it seems reasonable to propose a hardfork to the > difficulty adjustment algorithm so it can adapt quicker to such a > significant > drop in mining rate. BtcDrak tells me he has well-tested code for this in > his > altcoin, which has seen some roller-coaster hashrates, so it may even be > possible to have such a proposal ready in time to be deployed alongside > SegWit > to take effect in time for the upcoming subsidy halving. If this slips, I > think it may be reasonable to push for at least code-readiness before July, > and possibly roll it into any other hardfork proposed before or around that > time. > > I am unaware of any reason this would be controversial, so if anyone has a > problem with such a change, please speak up sooner rather than later. Other > ideas or concerns are of course welcome as well. > > Thanks, > > Luke > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > --089e0116076c06418c052d292736 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Since the root cause of what you are trying to a= ddress is the reward having, I'd suggest considering an adjustment to t= he having schedule.=C2=A0 Instead of their being a large supply shock every= four years, perhaps the reward could drop every 52,500 blocks (yearly), or= even at each difficulty adjustment, in such a way that the inflation curve= is smoothed out.=C2=A0 The exponential decay rate would be preserved, so o= verall economic philosophy would be preserved.

I'm guessin= g hesitance to this approach would lie in a reluctance to tinker with Bitco= in's 'economic contract', and slippery slope concerns about mig= ht be the next change (21M?).=C2=A0 However, I think it could actually incr= ease confidence in the system if the community is able to demonstrate a goo= d process for making such decisions, and show that we can separate the mean= ingful underlying principles, such as the coin limit and overall inflation = rate, from what is more akin to an implementation detail, as I consider the= large-step reward reduction to be.

I'm not too worri= ed about the impact of the having as is, but adjusting the economic paramet= er would be a safer and simpler way to address the concerns than to tinker = with the difficulty targeting mechanism, which is at the heart of Bitcoin&#= 39;s security

On Wed, Mar 2, 2016 at 6:56 AM, Luke Dashjr via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wro= te:
We are coming up on the subsidy halvi= ng this July, and there have been some
concerns raised that a non-trivial number of miners could potentially drop = off
the network. This would result in a significantly longer block interval, wh= ich
also means a higher per-block transaction volume, which could cause the blo= ck
size limit to legitimately be hit much sooner than expected. Furthermore, d= ue
to difficulty adjustment being measured exclusively in blocks, the time unt= il
it adjusts to compensate would be prolonged.

For example, if 50% of miners dropped off the network, blocks would be ever= y
20 minutes on average and contain double the transactions they presently do= .
Even double would be approximately 850-900k, which potentially bumps up
against the hard limit when empty blocks are taken into consideration. This=
situation would continue for a full month if no changes are made. If more miners drop off the network, most of this becomes linearly worse, but due t= o
hitting the block size limit, the backlog would grow indefinitely until the=
adjustment occurs.

To alleviate this risk, it seems reasonable to propose a hardfork to the difficulty adjustment algorithm so it can adapt quicker to such a significa= nt
drop in mining rate. BtcDrak tells me he has well-tested code for this in h= is
altcoin, which has seen some roller-coaster hashrates, so it may even be possible to have such a proposal ready in time to be deployed alongside Seg= Wit
to take effect in time for the upcoming subsidy halving. If this slips, I think it may be reasonable to push for at least code-readiness before July,=
and possibly roll it into any other hardfork proposed before or around that=
time.

I am unaware of any reason this would be controversial, so if anyone has a<= br> problem with such a change, please speak up sooner rather than later. Other=
ideas or concerns are of course welcome as well.

Thanks,

Luke
_______________________________________________
bitcoin-dev mailing list
bitcoin-dev@lists.= linuxfoundation.org
https://lists.linuxfoundation.org/mail= man/listinfo/bitcoin-dev

--089e0116076c06418c052d292736--