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From: =?UTF-8?B?Sm9zZXBoIEdsZWFzb24g4pGI?= <fireduck@gmail.com>
Date: Thu, 23 Jul 2015 19:57:38 +0000
Message-ID: <CA+ASnrGrBr6-QGaMx6j8aGZc+q+W6WpGy3okJRMa+TwHsnwxYg@mail.gmail.com>
To: Marcel Jamin <marcel@jamin.net>, Peter Todd <pete@petertodd.org>
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Cc: slurms--- via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Bitcoin Node Speed Test
Precedence: list

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That is how I read it as well.


On Thu, Jul 23, 2015 at 12:56 PM Marcel Jamin via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> He measured the upload capacity of the peers by downloading from them, or
> am I being dumb? :)
>
>
> 2015-07-23 18:05 GMT+02:00 Peter Todd via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org>:
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA256
>>
>>
>>
>> On 23 July 2015 10:19:59 GMT-04:00, slurms--- via bitcoin-dev <
>> bitcoin-dev@lists.linuxfoundation.org> wrote:
>> >This does not support the theory that the network has the available
>> >bandwidth for increased block sizes, as in its current state 37% of
>> >nodes would fail to upload a 20MB block to a single peer in under 20
>> >seconds (referencing a number quoted by Gavin). If the bar for
>> >suitability is placed at taking only 1% of the block time (6 seconds)
>> >to upload one block to one peer, then 69% of the network fails for 20MB
>> >blocks. For comparison, only 10% fail this metric for 1MB blocks.
>>
>> Note how due to bandwidth being generally asymetric your findings are
>> probably optimistic - you've measured download capacity. On top of that
>> upload is further reduced by the fact that multiple peers at once need to
>> be sent blocks for reliability.
>>
>> Secondly you're measuring a network that isn't under attack - we need
>> significant additional margin to resist attack as performance is
>> consensus-critical.
>>
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>>
>> _______________________________________________
>> 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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<div dir=3D"ltr">That is how I read it as well.<div><br></div></div><br><di=
v class=3D"gmail_quote"><div dir=3D"ltr">On Thu, Jul 23, 2015 at 12:56 PM M=
arcel Jamin via bitcoin-dev &lt;<a href=3D"mailto:bitcoin-dev@lists.linuxfo=
undation.org">bitcoin-dev@lists.linuxfoundation.org</a>&gt; wrote:<br></div=
><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1=
px #ccc solid;padding-left:1ex"><div dir=3D"ltr">He measured the upload cap=
acity of the peers by downloading from them, or am I being dumb? :)</div><d=
iv dir=3D"ltr"><div><br><div class=3D"gmail_extra"><br><div class=3D"gmail_=
quote">2015-07-23 18:05 GMT+02:00 Peter Todd via bitcoin-dev <span dir=3D"l=
tr">&lt;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"=
_blank">bitcoin-dev@lists.linuxfoundation.org</a>&gt;</span>:<br><blockquot=
e class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc sol=
id;padding-left:1ex">-----BEGIN PGP SIGNED MESSAGE-----<br>
Hash: SHA256<br>
<span><br>
<br>
<br>
On 23 July 2015 10:19:59 GMT-04:00, slurms--- via bitcoin-dev &lt;<a href=
=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">bitcoin=
-dev@lists.linuxfoundation.org</a>&gt; wrote:<br>
&gt;This does not support the theory that the network has the available<br>
&gt;bandwidth for increased block sizes, as in its current state 37% of<br>
&gt;nodes would fail to upload a 20MB block to a single peer in under 20<br=
>
&gt;seconds (referencing a number quoted by Gavin). If the bar for<br>
&gt;suitability is placed at taking only 1% of the block time (6 seconds)<b=
r>
&gt;to upload one block to one peer, then 69% of the network fails for 20MB=
<br>
&gt;blocks. For comparison, only 10% fail this metric for 1MB blocks.<br>
<br>
</span>Note how due to bandwidth being generally asymetric your findings ar=
e probably optimistic - you&#39;ve measured download capacity. On top of th=
at upload is further reduced by the fact that multiple peers at once need t=
o be sent blocks for reliability.<br>
<br>
Secondly you&#39;re measuring a network that isn&#39;t under attack - we ne=
ed significant additional margin to resist attack as performance is consens=
us-critical.<br>
<br>
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<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>
</div></div></blockquote></div><br></div></div></div>
_______________________________________________<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>

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