From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id DDCA6258 for ; Sat, 10 Dec 2016 17:39:59 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-ua0-f169.google.com (mail-ua0-f169.google.com [209.85.217.169]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 691FB156 for ; Sat, 10 Dec 2016 17:39:59 +0000 (UTC) Received: by mail-ua0-f169.google.com with SMTP id 12so46651636uas.2 for ; Sat, 10 Dec 2016 09:39:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=ZPMZSpmJTeTpjE51KFUfCP2rPOQgj+JdAVOtvb1+0f0=; b=a2PFTBS22XmP7RtrLvKEniTF0uvqJpBuAjKCAXwPrZre5pciG/0q7EkaITYyCoklUS /QweMmhNVFOYpS6UPNd65ykwNex6SFjCCDjSoPEWzbO3FUHSwuSuwOAlg7AJ3XTlohn4 9vWVxKeYCucmsg+fpCSY5TtpSKzqBCUzapnMQcVMEcXuqGc2Mw5vmMTiTFNgbb54T9Bs AjleoSObivDOff83X/YunoUFEB8CrZYpxP2oYs55vbMk2K2Vkj3zpLWcLiuvjK2iLsyT dvQmr6DMACP0neRxWMYP2uqxTHf2zvpUKY6+I1K9M2//emFQJwfE8E14w6QgDkLaUvaF wnfg== 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:from:date :message-id:subject:to; bh=ZPMZSpmJTeTpjE51KFUfCP2rPOQgj+JdAVOtvb1+0f0=; b=T5q2bxRLHgmF4hkN1hW2V8WGlNjxFOk/mkXhwiab/9B5Gzce/RavCwXXPZ4twqEiHG KOzPjXATC5yCDZxmrZsr5UTEWf7DmwD/YIVSyT26uvj4+JS7zYI5+Vnm7cN1Odzu8VYu yspTMXYs5uB4xZSQPMUjPsrzXEqfNF2U5oANHyVpYUxadtDcx9ysJREq/WByLZQB9+/S xNOEVyoJIPFExYE0JGMlP4ad8xVohUmlDIUVPTJfvaCKGLAXYgZHfEaJcUGUyNLN3phN X1cTvzL5Ti6zlYFFTQ1V7/0gRUzyyMuRHEi9vJgw3AdYMsTUtxNQAt630ODxcTLLlTuz Pmmw== X-Gm-Message-State: AKaTC03sk7q9qHJygXgX5sw0QphC/nUXl2gOf/q9JH8sbSwUsS8O5PbUk676Oxbd95pNa1VflZBBy53XMAVZjQ== X-Received: by 10.176.65.33 with SMTP id j30mr67086490uad.94.1481391598507; Sat, 10 Dec 2016 09:39:58 -0800 (PST) MIME-Version: 1.0 Received: by 10.31.108.202 with HTTP; Sat, 10 Dec 2016 09:39:57 -0800 (PST) In-Reply-To: References: From: Pieter Wuille Date: Sat, 10 Dec 2016 09:39:57 -0800 Message-ID: To: Daniele Pinna , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary=94eb2c124644009c960543515c81 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, HTML_MESSAGE, 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 Subject: Re: [bitcoin-dev] Managing block size the same way we do difficulty (aka Block75) X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Dec 2016 17:40:00 -0000 --94eb2c124644009c960543515c81 Content-Type: text/plain; charset=UTF-8 On Sat, Dec 10, 2016 at 4:23 AM, Daniele Pinna via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > We have models for estimating the probability that a block is orphaned > given average network bandwidth and block size. > > The question is, do we have objective measures of these two quantities? > Couldn't we target an orphan_rate < max_rate? > Models can predict orphan rate given block size and network/hashrate topology, but you can't control the topology (and things like FIBRE hide the effect of block size on this as well). The result is that if you're purely optimizing for minimal orphan rate, you can end up with a single (conglomerate of) pools producing all the blocks. Such a setup has no propagation delay at all, and as a result can always achieve 0 orphans. Cheers, -- Pieter --94eb2c124644009c960543515c81 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Sat, Dec 10, 2016 at 4:23 AM, Daniele Pinna via bitcoin= -dev <bitcoin-dev@lists.linuxfoundation.org&g= t; wrote:
<= blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px= #ccc solid;padding-left:1ex">
We have models for estimat= ing the probability that a block is orphaned given average network bandwidt= h and block size.=C2=A0

The question is,= do we have objective measures of these two quantities? Couldn't we tar= get an orphan_rate < max_rate?=C2=A0

<= /div>
Models can predict orphan rate given block size and network/hashr= ate topology, but you can't control the topology (and things like FIBRE= hide the effect of block size on this as well). The result is that if you&= #39;re purely optimizing for minimal orphan rate, you can end up with a sin= gle (conglomerate of) pools producing all the blocks. Such a setup has no p= ropagation delay at all, and as a result can always achieve 0 orphans.
<= br>
Cheers,

--
Pieter

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