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From: =?UTF-8?B?Sm9yZ2UgVGltw7Nu?= <jtimon@jtimon.cc>
To: Jeff Garzik <jgarzik@gmail.com>
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Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] The increase of max block size should be
determined by block height instead of block time
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Well, if it's not going to be height, I think median time of the previous
block is better than the time of the current one, and would also solve Chun
Wang's concerns.
But as said I prefer to use heights that correspond to diff recalculation
(because that's the window that bip9 will use for the later 95%
confirmation anyway).
On Dec 18, 2015 9:02 PM, "Jeff Garzik" <jgarzik@gmail.com> wrote:
> From a code standpoint, based off height is easy.
>
> My first internal version triggered on block 406,800 (~May 5), and each
> block increased by 20 bytes thereafter.
>
> It was changed to time, because time was the standard used in years past
> for other changes; MTP flag day is more stable than block height.
>
> It is preferred to have a single flag trigger (height or time), rather
> than the more complex trigger-on-time, increment-on-height, but any
> combination of those will work.
>
> Easy to change code back to height-based...
>
>
>
> On Fri, Dec 18, 2015 at 2:52 PM, Jorge Tim=C3=B3n <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
>> I agree that nHeight is the simplest option and is my preference.
>> Another option is to use the median time from the previous block (thus
>> you know whether or not the next block should start the miner confirmati=
on
>> or not). In fact, if we're going to use bip9 for 95% miner upgrade
>> confirmation, it would be nice to always pick a difficulty retarget bloc=
k
>> (ie block.nHeight % DifficultyAdjustmentInterval =3D=3D 0).
>> Actually I would always have an initial height in bip9, for softforks to=
o.
>> I would also use the sign bit as the "hardfork bit" that gets activated
>> for the next diff interval after 95% is reached and a hardfork becomes
>> active (that way even SPV nodes will notice when a softfork or hardfork
>> happens and also be able to tell which one is it).
>> I should update bip99 with all this. And if the 2 mb bump is
>> uncontroversial, maybe I can add that to the timewarp fix and th recover=
y
>> of the other 2 bits in block.nVersion (given that bip102 doesn't seem to
>> follow bip99's recommendations and doesn't want to give 6 full months as
>> the pre activation grace period).
>> On Dec 18, 2015 8:17 PM, "Chun Wang via bitcoin-dev" <
>> bitcoin-dev@lists.linuxfoundation.org> wrote:
>>
>>> In many BIPs we have seen, include the latest BIP202, it is the block
>>> time that determine the max block size. From from pool's point of
>>> view, it cannot issue a job with a fixed ntime due to the existence of
>>> ntime roll. It is hard to issue a job with the max block size unknown.
>>> For developers, it is also easier to implement if max block size is a
>>> function of block height instead of time. Block height is also much
>>> more simple and elegant than time.
>>> _______________________________________________
>>> 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
>>
>>
>
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<p dir=3D"ltr">Well, if it's not going to be height, I think median tim=
e of the previous block is better than the time of the current one, and wou=
ld also solve Chun Wang's concerns.<br>
But as said I prefer to use heights that correspond to diff recalculation (=
because that's the window that bip9 will use for the later 95% confirma=
tion anyway).</p>
<div class=3D"gmail_quote">On Dec 18, 2015 9:02 PM, "Jeff Garzik"=
<<a href=3D"mailto:jgarzik@gmail.com">jgarzik@gmail.com</a>> wrote:<=
br type=3D"attribution"><blockquote class=3D"gmail_quote" style=3D"margin:0=
0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr">Fro=
m a code standpoint, based off height is easy.<div><br></div><div>My first =
internal version triggered on block 406,800 (~May 5), and each block increa=
sed by 20 bytes thereafter.</div><div><br></div><div>It was changed to time=
, because time was the standard used in years past for other changes; MTP f=
lag day is more stable than block height.</div><div><br></div><div>It is pr=
eferred to have a single flag trigger (height or time), rather than the mor=
e complex trigger-on-time, increment-on-height, but any combination of thos=
e will work.</div><div><br></div><div>Easy to change code back to height-ba=
sed...</div><div><br></div><div><br></div></div><div class=3D"gmail_extra">=
<br><div class=3D"gmail_quote">On Fri, Dec 18, 2015 at 2:52 PM, Jorge Tim=
=C3=B3n <span dir=3D"ltr"><<a href=3D"mailto:bitcoin-dev@lists.linuxfoun=
dation.org" target=3D"_blank">bitcoin-dev@lists.linuxfoundation.org</a>>=
</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .=
8ex;border-left:1px #ccc solid;padding-left:1ex"><p dir=3D"ltr">I agree tha=
t nHeight is the simplest option and is my preference.<br>
Another option is to use the median time from the previous block (thus you =
know whether or not the next block should start the miner confirmation or n=
ot). In fact, if we're going to use bip9=C2=A0 for 95% miner upgrade co=
nfirmation, it would be nice to always pick a difficulty retarget block (ie=
block.nHeight % DifficultyAdjustmentInterval =3D=3D 0).<br>
Actually I would always have an initial height in bip9, for softforks too.<=
br>
I would also use the sign bit as the "hardfork bit" that gets act=
ivated for the next diff interval after 95% is reached and a hardfork becom=
es active (that way even SPV nodes will notice when a softfork=C2=A0 or har=
dfork happens and also be able to tell which one is it).<br>
I should update bip99 with all this. And if the 2 mb bump is uncontroversia=
l, maybe I can add that to the timewarp fix and th recovery of the other 2 =
bits in block.nVersion (given that bip102 doesn't seem to follow bip99&=
#39;s recommendations and doesn't want to give 6 full months as the pre=
activation grace period).</p><div><div>
<div class=3D"gmail_quote">On Dec 18, 2015 8:17 PM, "Chun Wang via bit=
coin-dev" <<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org"=
target=3D"_blank">bitcoin-dev@lists.linuxfoundation.org</a>> wrote:<br =
type=3D"attribution"><blockquote class=3D"gmail_quote" style=3D"margin:0 0 =
0 .8ex;border-left:1px #ccc solid;padding-left:1ex">In many BIPs we have se=
en, include the latest BIP202, it is the block<br>
time that determine the max block size. From from pool's point of<br>
view, it cannot issue a job with a fixed ntime due to the existence of<br>
ntime roll. It is hard to issue a job with the max block size unknown.<br>
For developers, it is also easier to implement if max block size is a<br>
function of block height instead of time. Block height is also much<br>
more simple and elegant than time.<br>
_______________________________________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">=
bitcoin-dev@lists.linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.org/mail=
man/listinfo/bitcoin-dev</a><br>
</blockquote></div>
</div></div><br>_______________________________________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">=
bitcoin-dev@lists.linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.org/mail=
man/listinfo/bitcoin-dev</a><br>
<br></blockquote></div><br></div>
</blockquote></div>
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