Experiments at tag leios-2025w26 (#425)

* Designed conflict experiment for KIS Leios
* K.I.S. results
* Analyzed conflict results
* Updated logbook

Author: bwbush

Logbook.md

@@ -2,15 +2,51 @@
 
 ## 2025-06-24
 
+### Conflict experiment on simplest Leios variant
+
+Experiments exploring the effect of conflicting transactions at 100 TPS for the simplest Leios variant were completed in [analysis/sims/2025w26/analysis.ipynb](analysis/sims/2025w26/analysis.ipynb).
+
+Assumptions:
+
+- mini-mainnet topology, with 100 Mb/s inter-nodal links
+- 100 tx/s
+- 0.2 IB/s
+- 2097.152 kB/IB maximum
+- 2.5 EB/stage
+- 10 slot/stage
+- aggressive pruning of memory pool
+- txs ordered by arrival in memory pool
+- no overcollateralization
+- no sharding
+- 0%, 25%, or 50% of transactions conflict with other transactions
+
+Findings:
+
+1. Spatial efficiency can be as low as 55%, which is due to the occasional production of an IB before the previous one is received.
+2. Transaction typically reach the ledger within 75 seconds.
+3. All non-conflicted transactions reach the ledger.
+4. NIC bandwidth of 20 Mb/s is sufficient: see figure below.
+5. Four vCPU cores are sufficient.
+6. Even the largest IBs (up to 2 MB) diffuse globally within 5 seconds: see figure below.
+7. IB traffic does not interfere with transaction, vote, EB, or RB traffic.
+8. The occasional large IBs benefit performance by diffusing before the mean time between IBs, which permits pruning of the memory pool before the next IB is typically produced.
+
+![Mean nodal network ingress at 100 TPS when IBs up to 2 MB are allowed](analysis/sims/2025w26/plots/cxs/ingress-average-area.png)
+
+![Diffusion of IBs at 100 TPS when IBs up to 2 MB are allowed](analysis/sims/2025w26/plots/cxs/elapsed-IB.png)
+
 ### Bandwidth experiment
 
 Experiments exploring the effect of bandwidth limits at 100 TPS and 300 TPS were completed in [analysis/sims/2025w25/analysis.ipynb](analysis/sims/2025w25/analysis.ipynb). Key findings follow:
 
-1. The following protocol parameters are sufficient for Leios high performance at 100 tx/s (or 300 tx/s): 1 IB/s (or 2 IB/s), 10 slot/stage, 328 kB/IB maximum, 1.5 EB/stage, and multiple shards.
+1. The following protocol parameters are sufficient for Leios high performance at 100 tx/s (or 300 tx/s): mini-mainnet topology, 1 IB/s (or 2 IB/s), 10 slot/stage, 328 kB/IB maximum, 1.5 EB/stage, and multiple shards.
 2. Spatial efficiency is 80%.
 3. All transactions reach the ledger, typically within two minutes.
 4. A 30 Mbps network interface card (NIC) is sufficient for the Leios node.
 5. A 4-core vCPU is also sufficient.
+6. The results are insensitive to inter-nodal link bandwidths greater than 50 Mb/s, and even at 10 Mb/s the effect of link bandwidth is small: see the figure below.
+
+![Diffusion of IBs at 300 TPS as a function of intra-nodal link bandwidth](analysis/sims/2025w25/plots/bw-2IBps/elapsed-IB.png)
 
 ## 2025-06-20
 

analysis/sims/2025w25/plots/bw-2IBps/elapsed-IB.png

@@ -0,0 +1,33 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p gzip
+
+set -e
+
+mkdir -p results/cxs
+
+for d in cxs
+do
+  for f in cpus lifecycle resources receipts
+  do
+    DIR=$(find $d -type f -name $f.csv.gz \( -not -empty \) -printf %h\\n -quit)
+    HL=$(sed -n -e '1p' "$DIR/case.csv")
+    HR=$(zcat "$DIR/$f.csv.gz" | sed -n -e '1p')
+    (
+      echo "$HL,$HR"
+      for g in $(find $d -type f -name $f.csv.gz \( -not -empty \) -printf %h\\n)
+      do
+        if [ ! -e "$g/stderr" ]
+        then
+          echo "Skipping $g because it has no stderr." >> /dev/stderr
+        elif [ -s "$g/stderr" ]
+        then
+          echo "Skipping $g because its stderr is not empty." >> /dev/stderr
+        else
+          BL=$(sed -n -e '2p' "$g/case.csv")
+          zcat "$g/$f.csv.gz" | sed -e "1d;s/^/$BL,/;s/null/NA/g"
+        fi
+      done
+    ) | pigz -p 3 -9c > results/$d/$f.csv.gz &
+  done
+done
+wait

analysis/sims/2025w26/analysis.ipynb

@@ -0,0 +1,223 @@
+# yaml-language-server: $schema=./config.schema.json
+
+################################################################################
+# Simulation Configuration File
+################################################################################
+#
+# This file contains the default configuration for running Leios simulations in
+# the Haskell simulation (`simulation/`) and the Rust simulation (`sim-rs/`).
+#
+################################################################################
+# Simulation Configuration
+################################################################################
+
+relay-strategy: "request-from-first"
+tcp-congestion-control: true
+multiplex-mini-protocols: true
+simulate-transactions: true
+treat-blocks-as-full: false
+cleanup-policies: ["cleanup-expired-vote"]
+timestamp-resolution-ms: 0.001
+
+################################################################################
+# Leios Protocol Configuration
+################################################################################
+
+leios-variant: full
+leios-stage-length-slots: 10
+leios-stage-active-voting-slots: 1
+leios-vote-send-recv-stages: false
+leios-late-ib-inclusion: true
+leios-header-diffusion-time-ms: 1000.0
+leios-mempool-sampling-strategy: ordered-by-id
+leios-mempool-aggressive-pruning: true
+# TODO: revise default
+praos-chain-quality: 100
+praos-fallback-enabled: false
+
+################################################################################
+# Transaction Configuration
+################################################################################
+
+tx-generation-distribution:
+  distribution: exp
+  lambda: 0.85
+  scale:  8.891
+tx-size-bytes-distribution:
+  distribution: log-normal
+  mu: 6.833
+  sigma: 1.127
+tx-conflict-fraction: 0
+tx-overcollateralization-factor-distribution:
+  distribution: constant
+  value: 0
+tx-validation-cpu-time-ms: 1.5
+tx-max-size-bytes: 16384
+tx-start-time: 60
+tx-stop-time: 660
+
+################################################################################
+# Ranking Block Configuration
+################################################################################
+
+# 1/leios-stage-length-slots, targeting one RB per pipeline.
+# Also 20s is current rate of praos blocks.
+rb-generation-probability: 5.0e-2
+# Eng. team targets 1kB as worst case upper bound.
+# Actual size fairly close.
+rb-head-size-bytes: 1024
+rb-body-max-size-bytes: 90112
+# Note: certificate generation/validation is not included in the
+# timings here, see cert-* fields.
+rb-generation-cpu-time-ms: 1.0
+rb-head-validation-cpu-time-ms: 1.0
+
+# On average, no Txs directly embedded in blocks.
+rb-body-legacy-praos-payload-avg-size-bytes: 0
+rb-body-legacy-praos-payload-validation-cpu-time-ms-constant: 50.0
+# the -per-byte component is meant to be using size as a (bad)
+# proxy for the complexity of the Txs included.
+rb-body-legacy-praos-payload-validation-cpu-time-ms-per-byte: 0.0005
+
+################################################################################
+# Input Block Configuration
+################################################################################
+
+ib-generation-probability: 0.20
+ib-shards: 1
+ib-shard-period-length-slots: 1
+ib-shard-group-count: 1
+
+# ProducerId  32
+# SlotNo      64
+# VRF proof   80
+# Body hash   32
+# RB Ref      32
+# Signature   64
+# Total       304
+#
+# NOTE: using a KES Signature (like for Praos headers)
+#       would instead more than double the total to 668.
+#       And even 828 including Op Cert.
+ib-head-size-bytes: 304
+# 98KB to optimize for 3 TCP round trips
+ib-body-avg-size-bytes: 98304
+ib-body-max-size-bytes: 2097152
+# Here we also use praos blocks as ballpark estimate.
+# Sec 2.3 Forging, of the benchmark cluster report, lists
+#   * Slot start to announced: 0.12975s
+ib-generation-cpu-time-ms: 130.0
+ib-head-validation-cpu-time-ms: 1.0
+ib-body-validation-cpu-time-ms-constant: 50.0
+ib-body-validation-cpu-time-ms-per-byte: 0.0005
+ib-diffusion-strategy: "freshest-first"
+
+# Haskell prototype relay mini-protocol parameters.
+ib-diffusion-max-bodies-to-request: 1
+ib-diffusion-max-headers-to-request: 100
+ib-diffusion-max-window-size: 100
+
+################################################################################
+# Endorsement Block Configuration
+################################################################################
+
+# We want one per pipeline, but not too many.
+eb-generation-probability: 2.5
+# ProducerId  32
+# SlotNo      64
+# VRF proof   80
+# Signature   64
+# Total       240
+#
+# See Note about signatures on ib-head-size-bytes.
+eb-size-bytes-constant: 240
+# IB hash
+eb-size-bytes-per-ib: 32
+# Collecting the IBs to reference and cryptography are the main tasks.
+# A comparable task is maybe mempool snapshotting.
+# Sec 2.3 Forging, of the benchmark cluster report, lists
+#   * Mempool snapshotting: 0.07252s
+# 75ms then seems a generous estimate for eb generation.
+eb-generation-cpu-time-ms: 75.0
+# Validating signature and vrf proof, as in other headers.
+eb-validation-cpu-time-ms: 1.0
+
+eb-diffusion-strategy: "peer-order"
+
+# Haskell prototype relay mini-protocol parameters.
+eb-diffusion-max-bodies-to-request: 1
+eb-diffusion-max-headers-to-request: 100
+eb-diffusion-max-window-size: 100
+
+# The maximum age of EBs included in RBs.
+# A an EB from slot `s` can only be included in RBs
+# up to slot `s+eb-max-age-slots`.
+# In short leios we expect votes to diffuse within 3 stages lengths of
+# EB generation, we allow for 2 more stage lengths to account for
+# variance in the interval within RBs.
+eb-max-age-slots: 240
+
+# The maximum age of EBs to be relayed.
+# An EB from slot `s` will only be relayed
+# up to slot `s+eb-max-age-for-relay-slots`.
+eb-max-age-for-relay-slots: 40
+
+# The maximum size of transactions (in bytes) which an EB can reference.
+# Only relevant when running with the "full-without-ibs" variant.
+eb-referenced-txs-max-size-bytes: 16384000
+
+################################################################################
+# Vote Configuration
+################################################################################
+
+# Cryptography related values taken from [vote-spec](crypto-benchmarks.rs/Specification.md)
+# using weighted averages of 80% persistent and 20% non-persistent.
+
+# vote-spec#Committe and quorum size
+#
+# Note: this is used as the expected amount of total weight of
+# generated votes in the sims.
+vote-generation-probability: 500.0
+# vote-spec#"Committe and quorum size"
+# 60% of `vote-generation-probability`
+vote-threshold: 300
+# vote-spec#"Generate vote" 0.8*135e-3 + 0.2*280e-3
+vote-generation-cpu-time-ms-constant: 164.0e-3
+# No benchmark yet.
+vote-generation-cpu-time-ms-per-ib: 0
+# vote-spec#"Verify vote" 0.8*670e-3 + 0.2*1.4
+vote-validation-cpu-time-ms: 816.0e-3
+# The `Vote` structure counted in the -per-eb already identifies slot
+# (in Eid) and voter. We can assume a vote bundle is all for the same
+# voter and slot, so for non-persistent voters we could factor their
+# PoolKeyHash (28bytes) here, but that is for 20% of cases.
+# More relevant if EB generation is very high.
+vote-bundle-size-bytes-constant: 0
+# vote-spec#Votes 0.8*90 + 0.2*164
+vote-bundle-size-bytes-per-eb: 105
+
+vote-diffusion-strategy: "peer-order"
+
+# Haskell prototype relay mini-protocol parameters.
+vote-diffusion-max-bodies-to-request: 1
+vote-diffusion-max-headers-to-request: 100
+vote-diffusion-max-window-size: 100
+
+################################################################################
+# Certificate Configuration
+################################################################################
+
+# vote-spec - certificate size plot.
+# Realistic stake distributions need about 7 kilobytes for the certificate.
+cert-size-bytes-constant: 7168
+cert-size-bytes-per-node: 0
+
+# For certificate timings we have bulk figures for realistic scenarios,
+# so we do not attempt to give -per-node (i.e. per-voter) timings.
+#
+# vote-spec#"Generate certificate"
+cert-generation-cpu-time-ms-constant: 90.0
+cert-generation-cpu-time-ms-per-node: 0
+# vote-spec#"Verify certificate"
+cert-validation-cpu-time-ms-constant: 130.0
+cert-validation-cpu-time-ms-per-node: 0

analysis/sims/2025w26/combine-results.sh

@@ -0,0 +1,2 @@
+Simulator,Conflict fraction
+Rust,0.00