igneum/docs/analysis/block-rate-devnet2.md

Block rate on Devnet 2: 10 blocks per second against 1, on the rented fleet

6 October 2026, the project lead's experiment (through the coordinator, 17:5xZ): "Devnet 2 at a higher block rate for solo miners (Kaspa's answer)". Branch gpu-fleet; the node profile on the fork branch devnet2-bps (1279a1d6 on release-0.3.14-node 4c6b129d): a suffixed devnet started with IGNEUMD_DEVNET_BPS=10 (or 5) runs BlockrateParams::new::<10>() with the TenBps subsidy and target time, Kaspa's Crescendo-style constants for that rate (k 124, merge depth, sample rates, mergeset limit, parents, coinbase maturity from consensus/core/src/config/bps.rs); the shared devnet never reads the variable, so the live digest and rules are untouched. Built on igneum-build-1 (tools/build-remote.sh). Numbers land below as they are measured; every figure carries its source file under ~/Desktop/fleet/bps/.

The runs

Run	Chain	Miners	Length	What is read
A	igneum-devnet-2, fresh genesis, 10 bps	the 38 wave pods plus the 4 Devnet 2 boxes (42 cards, about 2.0 GH/s)	60 min	blocks per second achieved, blue and red blocks per minute (orphan rate), blue score growth, max reorg depth, checkpoint lock delay and weight at this voter count, p2p bytes per node per minute, node CPU and RSS, exec lag (height minus executed tip), payout intervals per miner from the coinbase records
B	the same boxes, fresh genesis, 1 bps	the same	30 min	the same (the control)
A2	three relays, 10 bps	the same	dropped: the network lane's read of run A (reds from node throughput, not topology) made a topology run uninformative without per-block CPU profiling on a pod; no provider gave inbound ports for a mesh

Payout interval per tier, from each run's measured block rate and the chain's hash: a 4070 at 28 MH/s, a 5090 at 128 MH/s, an 8x 4090 rig at 459 MH/s, at tonight's network hash and extrapolated to 1, 10 and 100 TH/s networks (interval = blocks per second x miner share, the arithmetic in tools/fleet/bps-collect.py).

Measured

Run A: 10 blocks per second, star topology (19:17Z to 20:25Z)

Seed: the fork's igneumd (83702a35, IGNEUMD_DEVNET_BPS=10) on igneum-build-1 (188.40.146.49:26611, a public port), genesis f682b78a4e64f0d2, digest 436d62a5b962e1c2, mining from 19:17:26Z. Miners: dn2-1/2/3 from 19:25Z, the 38 wave pods from 19:26Z (each node beside the pod's live-devnet node on other ports, each dialling the seed only: no pod has an inbound port), 41 peers on the seed. Collector rows every minute in ~/Desktop/fleet/bps/A.jsonl (the first 20 minutes carry the seed's log counts only; the watch line from 19:37Z after the seed's miner binary was staged).

Read	Value	Source
Blocks at 10 min (19:36Z)	5,733 (12.4 blocks/s over the last 159 s)	seed watch line
Blue score at 10 min	1,307 (77 percent of blocks red)	the same
Blocks 19:37Z to 20:24Z (47 min)	7,204 to 19,153: 4.25 blocks/s; blue +2,926: 1.09 blue/s; red share 77.6 percent	A.jsonl
Rate by six-minute interval	7.7, 1.9, 2.9, 2.8, 5.9, 4.2, 3.2, 5.1 blocks/s; blue 0.6 to 1.6/s	A.jsonl
Tips	246 at 10 min, 295 to 662 through the hour, rising	A.jsonl
Difficulty	6,719 at 19:33Z, 3,551 at 19:36Z, 1,307 at 19:42Z, falling the whole hour (the rule reads the blue rate under target and eases)	seed watch, by hand
Max selected-chain reorg	55 blocks (a late pod unwinding its genesis-only view at join)	seed log
Exec follower	tip 84 at 19:30Z, 240 at 20:19Z: 0.05 blocks/s against 1.1 blue/s; lag 18,901 blocks at the end	igneum_getExecStatus on the seed
Finality	18 locks over the run (the voters are the 42 miners' keys)	seed log

What it says: with 42 cards on a 10 blocks/s profile the DAG ran at 4 to 12 blocks a second but the selected chain at about 1.1 blue blocks a second, three in four blocks red, tips in the hundreds, and the difficulty rule eased all hour because it measures the blue rate. The Horizon network lane's read of the same rows (docs/analysis/horizon/network.md): the reds came from node throughput, not the star: the seed spent 61 to 345 ms of CPU per accepted block (mergeset 8 to 200), a 100 ms-per-block knee at 10 blocks/s, RSS 5.4 GB at 12,000 blocks, and the propagation model gives 0.0 percent red for both star and mesh at the measured latencies. So a topology run (A2) proves nothing without per-block CPU profiling on a pod, and was dropped. A true mesh was also not possible tonight: no provider gave a pod with an inbound p2p port, the live devnet has the same star (every rented node dials the two hands and the hub), and the standing-fleet ports rule in docs/plans/gpu-fleet.md is the fix.

The exec follower is the second finding: at 1.1 blue blocks a second it executed 0.05 blocks a second, so a 10 blocks/s chain with payload would leave every wallet and prover reading state hours behind the tip within the first hour.

Run B: 1 block per second, the control, same boxes (20:25Z to 20:58Z)

Seed restarted on a fresh genesis without the profile variable (1 block/s, the devnet's rule), the same 42 boxes, each wiped and rejoined (FRESH=1), rows in ~/Desktop/fleet/bps/B.jsonl from 20:28Z.

Read	Value	Source
Blocks 20:28Z to 20:58Z (29.5 min)	2,679 to 5,171: 1.41 blocks/s; blue +2,099: 1.19 blue/s; red share 15.8 percent over the window	B.jsonl
The first six minutes	3.05 blocks/s against 1.93 blue/s: the join burst (42 nodes arriving on a chain minutes old, the late ones unwinding genesis-only views; max reorg 16)	B.jsonl
From 20:34Z on, by six-minute interval	1.01, 0.99, 0.94, 1.05 blocks/s and 1.01, 0.99, 0.95, 1.05 blue/s: red share under 2 percent	B.jsonl
Tips	21 at 20:28Z, 1 to 3 from 20:34Z	B.jsonl
Difficulty	19.9 M at 20:28Z, 477 M by 20:34Z, 453 to 482 M after: settled in six minutes and flat	B.jsonl
Max selected-chain reorg	16 (the join)	seed log
Exec follower	tip 188 at 20:28Z, 1,003 at 20:58Z: 0.46 blocks/s against 1.0 blue/s, lag 4,168 at the end and growing	igneum_getExecStatus
Finality	0 locks in 30 minutes (the chain was 30 minutes old; the window had not filled)	seed log

What it says: the same 42 cards that made a 77 percent red DAG at the 10 blocks/s profile made a chain with one to three tips and under 2 percent red at 1 block/s, with the difficulty settled in six minutes. The exec follower still ran under the chain (0.46 against 1.0), which is the follower's own ceiling on these pods and a finding for the proving lane, not for the rate.

Per tier

From the collector's arithmetic (interval = 1 / (blocks per second x miner hash / network hash)); run A's "blocks" are DAG blocks of which three in four were red, so its payout column is read at a quarter.

Network hash	Miner	Run A (4.87 DAG blocks/s, 1.09 blue/s)	Run B (1.19 blue blocks/s)
tonight, 2.0 GH/s	4070, 28 MH/s	a block every 0.2 min, of which 1 in 4 pays	a block every 0.8 min, nearly all pay
tonight, 2.0 GH/s	5090, 128 MH/s	every 0.1 min	every 0.2 min
tonight, 2.0 GH/s	8x 4090 rig, 459 MH/s	continuous	every 0.1 min
1 TH/s	4070	every 2.0 h (DAG), about 8 h in blue blocks	every 7.0 h
1 TH/s	5090	every 27 min (DAG), about 1.8 h blue	every 1.5 h
1 TH/s	8x 4090 rig	every 7.4 min (DAG), about 30 min blue	every 26 min
10 TH/s	4070	every 20 h (DAG), about 3.4 days blue	every 2.9 days
10 TH/s	5090	every 4.5 h (DAG), about 18 h blue	every 15 h
10 TH/s	8x 4090 rig	every 1.2 h (DAG), about 5 h blue	every 4.3 h
100 TH/s	4070	every 8.5 days (DAG), about a month blue	every 29 days
100 TH/s	5090	every 1.9 days (DAG), about a week blue	every 6.4 days
100 TH/s	8x 4090 rig	every 12 h (DAG), about 2 days blue	every 1.8 days

Consequence per tier: a home 4070 at a 10 TH/s network waits about three days for a paying block either way (the 10 blocks/s profile's extra DAG blocks are red, so the solo miner's variance does not fall by 10x, only by the blue-rate ratio of 1.09 to 1.19, which is nothing); the rig and the 5090 see the same. The way to a shorter wait for the small card is the pool, not the block rate. GHOSTDAG pays red blocks nothing under this rule set, so a higher rate is only worth having where the blue rate rises with it, which needs the node to process a block in well under 100 ms at mergeset 248.

The recommendation for mainnet's rate

From the Horizon network lane (docs/analysis/horizon/network.md), carried here as the experiment's recommendation: 1 block per second for the public testnet and the launch; 10 blocks per second behind three gates, each measured before the rate moves: (1) per-block node CPU under 50 ms at mergeset 248 on a laptop core (tonight's seed: 61 to 345 ms, a knee at 100 ms per block at 10 blocks/s, RSS 5.4 GB at 12,000 blocks); (2) finality constants and the clock cap expressed in DAA seconds, so a rate change moves no human-time guarantee; (3) vote aggregation, so 100 voters at 10 blocks/s do not multiply the certificate traffic by ten. Two fleet rules from the runs: a box never mines from a genesis-only view, it syncs first (the 55-block reorg of run A and the 16-block one of run B were late pods unwinding); and the exec follower's rate (0.05 and 0.46 blocks/s on these pods) is the state layer's ceiling and must be measured beside any block-rate change.