Subject: Re: [Bitcoin-development] we can all relax now

From: Kyle Jerviss <[email-masked]>
Date: Wed, 06 Nov 2013 23:24:48 -0600

What I want is configurable 1/10/100 millisecond ticks, and accurate 
flow of information.

It doesn't seem necessary to really emulate the whole protocol, nor to 
be overly concerned with the content of messages, nor to simulate every 
little housekeeping step or network message.

I'm not looking for a bitcoin-network-in-a-bottle, I just want to see 
flows.  In the current situation, how often does a miner win if they 
hold their block until they see another one?  How does that change with 
various numbers of remote sensors?

Other applications in the future could very well involve transaction 
spread, double spends, network partitions, transaction replacement, etc.

If the simulation run in question involves blocks, I'd like realistic 
latencies for blocks.  If it is about transactions, the latencies should 
be realistic for transactions.

What is realistic for those?  That brings me to...

I'll kick in another 1 BTC for an instrumentation package for the 
reference client.  Same conditions as before.  A runtime option, 
disabled by default, that collects data for the simulator.  If this 
creates an uproar, I'll also accept a compile-time option. Support 
dumping to a file that can be uploaded to a parser as the bare minimum, 
and if you are feeling clever, add automatic uploads to a server 
specified in the conf file, or whatever.  All data should be anonymous, 
of course.  Local file should be in a format that humans can read (JSON, 
XML, CSV, etc) so that people can verify that the data is indeed anonymous.

I want stats on peers (number, turnover, latency, in/out, etc), stats on 
local operations (I/O stats, sigs per second when verifying a block, 
fraction of sig cache hits when validating, etc) and whatever else might 
be useful to a simulator.  Each parameter should collect min, max, mean, 
std. deviation, etc so that the simulator can provide realistic virtual 
nodes.

Also, I don't want anyone to think that they need to satisfy me 
personally to collect on either of these two bounties.  I will pay mine 
for a product that is generally along the lines I have laid out, if a 
couple of the core devs (Gavin, Greg, Jeff, sipa, Luke, etc) agree that 
your work is useful.

Christophe Biocca wrote:
>
> I might try building this sometime soon. I think it may also serve an 
> educational purpose when trying to understand the whole network's 
> behaviour.
>
> What level of accuracy are we looking for though? Obviously we need to 
> fully emulate the steps of the network protocol, and we need to be 
> able to specify time taken for transmission/processing for each node. 
> Do we care about the actual contents of the messages (to be able to 
> simulate double spend attempts, invalid transactions and blocks, SPV 
> node communication), and their validation (actual signatures and proof 
> of work)?
>
> I imagine the latter is pretty useless, beyond specifying that the 
> signature/proof of work is valid/invalid.
>
> If we could build up a set of experiments we'd like to run on it, it 
> would help clarify what's needed.
>
> Off the top of my head:
>
> - Peter Todd's miner strategy of sending blocks to only 51% of the 
> hashpower.
> - Various network split conditions, and how aware of the split nodes 
> would be (and the effect of client variability).
> - Testing the feasability of network race double spends, or Finney 
> attacks.
> - Various network partition scenarios.
> - Tricking SPV nodes.
>
> On Nov 6, 2013 6:37 AM, "Jeff Garzik" <[email-masked] 
> <mailto:[email-masked]>> wrote:
>
>     I will contribute 1 BTC to this bounty, under same terms and
>     expiration.
>
>
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