From: Luke Dashjr <luke@dashjr•org>
To: shaolinfry <shaolinfry@protonmail•ch>
Cc: "bitcoin-dev@lists•linuxfoundation.org"
<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Height based vs block time based thresholds
Date: Wed, 5 Jul 2017 04:10:43 +0000 [thread overview]
Message-ID: <201707050410.45217.luke@dashjr.org> (raw)
In-Reply-To: <00qcLaDJFDoC9D6644P_aLf7_n5B1pqCPj_c02QlqySsrJLsB6TZipXMD8L7l3lJcw5NoLP6dphCMruKJCIMkJUIDYbIw0iDd322vsNFmNw=@protonmail.ch>
It's not pointless: it's a wake-up call for miners asleep "at the wheel", to
ensure they upgrade in time. Not having a mandatory signal turned out to be a
serious bug in BIP 9, and one which is fixed in BIP 148 (and remains a problem
for BIP 149 as-is). Additionally, it makes the activation decisive and
unambiguous: once the lock-in period is complete, there remains no question as
to what the correct protocol rules are.
It also enables deploying softforks as a MASF, and only upgrading them to UASF
on an as-needed basis.
Luke
On Wednesday 05 July 2017 4:00:38 AM shaolinfry wrote:
> Luke,
> I previously explored an extra state to require signalling before
> activation in an earlier draft of BIP8, but the overall impression I got
> was that gratuitous orphaning was undesirable, so I dropped it. I
> understand the motivation behind it (to ensure miners are upgraded), but
> it's also rather pointless when miners can just fake signal. A properly
> constructed soft fork is generally such that miners have to deliberately
> do something invalid - they cannot be tricked into it... and miners can
> always chose to do something invalid anyway.
>
> > -------- Original Message --------
> > From: luke@dashjr•org
> > To: bitcoin-dev@lists•linuxfoundation.org, shaolinfry
> > <shaolinfry@protonmail•ch> I"ve already opened a PR almost 2 weeks ago
> > to do this and fix the other issues BIP 9 has.
> > https://github.com/bitcoin/bips/pull/550
> > It just needs your ACK to merge.
> >
> > On Wednesday 05 July 2017 1:30:26 AM shaolinfry via bitcoin-dev wrote:
> >> Some people have criticized BIP9"s blocktime based thresholds arguing
> >> they are confusing (the first retarget after threshold). It is also
> >> vulnerable to miners fiddling with timestamps in a way that could
> >> prevent or delay activation - for example by only advancing the block
> >> timestamp by 1 second you would never meet the threshold (although this
> >> would come a the penalty of hiking the difficulty dramatically). On the
> >> other hand, the exact date of a height based thresholds is hard to
> >> predict a long time in advance due to difficulty fluctuations. However,
> >> there is certainty at a given block height and it"s easy to monitor. If
> >> there is sufficient interest, I would be happy to amend BIP8 to be
> >> height based. I originally omitted height based thresholds in the
> >> interests of simplicity of review - but now that the proposal has been
> >> widely reviewed it would be a trivial amendment.
next prev parent reply other threads:[~2017-07-05 4:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-05 1:30 shaolinfry
2017-07-05 2:25 ` Troy Benjegerdes
2017-07-05 3:39 ` Bram Cohen
2017-07-05 3:50 ` Luke Dashjr
2017-07-05 4:00 ` shaolinfry
2017-07-05 4:10 ` Luke Dashjr [this message]
2017-07-05 19:44 ` Hampus Sjöberg
2017-07-06 17:20 ` Jorge Timón
2017-07-06 17:41 ` Eric Voskuil
2017-07-05 8:06 ` Gregory Maxwell
2017-07-05 8:54 ` Kekcoin
2017-07-06 20:43 ` Luke Dashjr
2017-07-07 5:52 ` shaolinfry
2017-07-07 9:51 ` Jorge Timón
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