We should avoid discussing actual hard fork/softfork deployment methodologies when discussing blocksize proposals because deployment is a separate issue. As a recent case in point, look at how BIP65 (CHECKLOCKTIMEVERIFY) specifically avoided the issue of how to deploy. That lead to a focused discussion of the functionality and relatively quick inclusion.
Deployment really is a separate issue than the mechanics of how BIP100 will function after activation. On Thu, Sep 3, 2015 at 8:57 AM, jl2012 via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote: > Some comments: > > The 75% rule is meaningless here. Since this is a pure relaxation of rules, > there is no such thing as "invalid version 4 blocks" > > The implication threshold is unclear. Is it 95% or 80%? > > Softfork requires a very high threshold (95%) to "attack" the original fork. > This makes sure that unupgraded client will only see the new fork. > In the case of hardfork, however, the new fork is unable to attack the > original fork, and unupgraded client will never see the new fork. The > initiation of a hardfork should be based on its acceptance by the economic > majority, not miner support. 95% is an overkill and may probably never > accomplished. I strongly prefer a 80% threshold rather than 95%. > > As I've pointed out, using 20-percentile rather than median creates an > incentive to 51% attack the uncooperative minority. > https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010690.html > > Having said that, I don't have a strong feeling about the use of > 20-percentile as threshold to increase the block size. That means the block > size is increased only when most miners agree, which sounds ok to me. > > However, using 20-percentile as threshold to DECREASE the block size could > be very dangerous. Consider that the block size has been stable at 8MB for a > few years. Everyone are happy with that. An attacker would just need to > acquire 21% of mining power to break the status quo and send us all the way > to 1MB. The only way to stop such attempt is to 51% attack the attacker. > That'd be really ugly. > > For technical and ethical reasons, I believe the thresholds for increase and > decrease must be symmetrical: increase the block size when the x-percentile > is bigger than the current size, decrease the block size when the > (100-x)-percentile is smaller than the current size. The overall effect is: > the block size remains unchanged unless 80% of miners agree to. > > Please consider the use of "hardfork bit" to signify the hardfork: > > https://www.reddit.com/r/bitcoin_devlist/comments/3ekhg2/bip_draft_hardfork_bit_jl2012_at_xbthk_jul_23_2015/ > > https://github.com/jl2012/bips/blob/master/hardforkbit.mediawiki > > Or, alternatively, please combine the hardfork with a softfork. I'm > rewriting the specification as follow (changes underlined): > > Replace static 1M block size hard limit with a floating limit ("hardLimit"). > > hardLimit floats within the range 1-32M, inclusive. > > Initial value of hardLimit is 1M, preserving current system. > > Changing hardLimit is accomplished by encoding a proposed value within a > block's coinbase scriptSig. > > Votes refer to a byte value, encoded within the pattern "/BV\d+/" Example: > /BV8000000/ votes for 8,000,000 byte hardLimit. If there is more than one > match with with pattern, the first match is counted. > Absent/invalid votes and votes below minimum cap (1M) are counted as 1M > votes. Votes above the maximum cap (32M) are counted as 32M votes. > A new hardLimit is calculated at each difficult adjustment period (2016 > blocks), and applies to the next 2016 blocks. > Calculate hardLimit by examining the coinbase scriptSig votes of the > previous 12,000 blocks, and taking the 20th percentile and 80th percentile. > New hardLimit is the median of the followings: > > min(current hardLimit * 1.2, 20-percentile) > max(current hardLimit / 1.2, 80-percentile) > current hardLimit > > version 4 block: the coinbase of a version 4 block must match this pattern: > "/BV\d+/" > 70% rule: If 8,400 of the last 12,000 blocks are version 4 or greater, > reject invalid version 4 blocks. (testnet4: 501 of last 1000) > 80% rule ("Point of no return"): If 9,600 of the last 12,000 blocks are > version 4 or greater, reject all version <= 3 blocks. (testnet4: 750 of last > 1000) > Block version number is calculated after masking out high 16 bits (final bit > count TBD by versionBits outcome). > > Jeff Garzik via bitcoin-dev 於 2015-09-02 23:33 寫到: >> BIP 100 initial public draft: >> https://github.com/jgarzik/bip100/blob/master/bip-0100.mediawiki [1] >> >> Emphasis on "initial" This is a starting point for the usual open >> source feedback/iteration cycle, not an endpoint that Must Be This >> Way. >> >> >> >> Links: >> ------ >> [1] https://github.com/jgarzik/bip100/blob/master/bip-0100.mediawiki >> >> _______________________________________________ >> bitcoin-dev mailing list >> bitcoin-dev@lists.linuxfoundation.org >> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > _______________________________________________ bitcoin-dev mailing list bitcoin-dev@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
