Warnet + Increase Tx Relay Rate

Implementation
2

I was thinking something like this.

  1. have three parameters:
    • size of the network (100 nodes total, 90 listening, 10 non-listening)
    • tx creation rate (5tx/s to 70tx/s)
    • tx confirmation rate (3.75tx/s, 7.5tx/s, 15tx/s)
  2. start the nodes
    • run 26.0 out of the box consistently everywhere
    • start each node with its own wallet
    • maybe reduce MAX_OUTBOUND_FULL_RELAY_CONNECTIONS from 8 to 5 (to simulate the greater distance between nodes in a network of 10k-100k nodes, despite only having 100 nodes)
    • set -blockmaxweight to 999000, 1998000 or 3996000 depending on the target tx confirmation rate
  3. start mining blocks
    • every 10 minutes, select a random peer, mine a block
    • once a block reward matures, create a tx splitting the reward into 0.1 BTC outputs at a 500sat/vb feerate
  4. generate small txs at the nominated rate:
    • 1-in, 1-out taproot tx is 111 vbytes. if signatures are annoyingly slow, make it p2wsh where the script is “<61B push> OP_DROP OP_TRUE”, which should also be 111 vbytes
    • 1-in, 0-out tx to burn funds: ie, just an 0-value 32 byte OP_RETURN output when the input amount is below 0.05 BTC perhaps?
    • output should just be a new change address
    • fee rate should estimatesmartfee 5 multiplied by exp(random()*0.2-0.1)
    • do this randomly amongst all peers, eg get 5tx/s overall by having 100 nodes generate 1tx every 20s

The easiest thing to report is the performance of compact block relay, so run with debug=cmpctblock look at the “Successfully reconstructed block” lines, eg:

2023-12-18T02:01:46.628563Z [cmpctblock] Successfully reconstructed block
   00000000000000000001083bc8296739b4a65f1264f69104a52f16962a24af5b
   with 1 txn prefilled, 3513 txn from mempool (incl at least 9 from extra pool)
   and 7 txn requested

In particular, my expectation is that if you increase the sustained tx creation rate above 18 tx/s you’ll start to get inconsistent mempools and the “txn requested” number may rise. Having those inconsistencies appear at the top of the mempool probably requires you to be doing RBF or to have chains of unconfirmed transactions, particularly involving CPFP.

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