sim-rs: implement random sampling

Author: SupernaviX

data/simulation/config.d.ts

@@ -45,6 +45,10 @@ export interface Config {
    * This is Δhdr from the Leios paper.
    * */
   "leios-header-diffusion-time-ms": number;
+  /**
+   * The strategy to use when selecting TXs from the Leios mempool.
+   */
+  "leios-mempool-sampling-strategy": MempoolSamplingStrategy;
   /**
    * Praos blockchain quality parameter.
    * This is η from the Leios paper.
@@ -248,4 +252,11 @@ export enum LeiosVariant {
   Full = "full",
   /** Full Leios Without IBs: EBs reference TXs directly, as well as other EBs */
   FullWithoutIbs = "full-without-ibs",
-}
+}
+
+export enum MempoolSamplingStrategy {
+  /** Include transactions in order by ID (corresponds to generation time). */
+  OrderedById = "ordered-by-id",
+  /** Include transactions in random order. */
+  Random = "random",
+}

data/simulation/config.default.yaml

@@ -28,6 +28,7 @@ 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
 # TODO: revise default
 praos-chain-quality: 40
 praos-fallback-enabled: true

data/simulation/config.schema.json

@@ -91,6 +91,10 @@
       },
       "type": "object"
     },
+    "MempoolSamplingStrategy": {
+      "enum": ["ordered-by-id", "random"],
+      "type": "string"
+    },
     "NormalDistribution": {
       "properties": {
         "distribution": {
@@ -269,6 +273,10 @@
       "description": "Extends Leios so that EB producers include IBs directly from previous pipelines\nwhere no certified EB was observed.\n\nOnly supported by Rust simulation.",
       "type": "boolean"
     },
+    "leios-mempool-sampling-strategy": {
+      "$ref": "#/definitions/MempoolSamplingStrategy",
+      "description": "The strategy to use when selecting TXs from the Leios mempool."
+    },
     "leios-stage-active-voting-slots": {
       "additionalProperties": false,
       "properties": {},

data/simulation/variants/config.full.yaml

@@ -1,7 +1,11 @@
 leios-variant: full
 
+# How to choose transactions from the mempool when producing IBs.
+# "Random" is meant to ensure that different producers include different TXs.
+leios-mempool-sampling-strategy: random
+
 # Allow EBs to include IBs from previous slots
 leios-late-ib-inclusion: true
 
 # Chain quality controls how far back EB recursion can reach.
-praos-chain-quality: 40
+praos-chain-quality: 100

sim-rs/parameters/full.yaml

@@ -1,3 +1,4 @@
 leios-variant: full
+leios-mempool-sampling-strategy: random
 leios-late-ib-inclusion: true
-praos-chain-quality: 40
+praos-chain-quality: 100

sim-rs/sim-core/src/config.rs

@@ -62,6 +62,7 @@ pub struct RawParameters {
     pub leios_stage_active_voting_slots: u64,
     pub leios_late_ib_inclusion: bool,
     pub leios_header_diffusion_time_ms: f64,
+    pub leios_mempool_sampling_strategy: MempoolSamplingStrategy,
     pub praos_chain_quality: u64,
     pub praos_fallback_enabled: bool,
 
@@ -149,6 +150,13 @@ pub enum RelayStrategy {
     RequestFromFirst,
 }
 
+#[derive(Debug, Copy, Clone, Deserialize, PartialEq, Eq)]
+#[serde(rename_all = "kebab-case")]
+pub enum MempoolSamplingStrategy {
+    OrderedById,
+    Random,
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 #[serde(rename_all = "kebab-case")]
 pub struct RawTopology {
@@ -439,6 +447,7 @@ pub struct SimConfiguration {
     pub(crate) praos_fallback: bool,
     pub(crate) header_diffusion_time: Duration,
     pub(crate) relay_strategy: RelayStrategy,
+    pub(crate) mempool_strategy: MempoolSamplingStrategy,
     pub(crate) praos_chain_quality: u64,
     pub(crate) block_generation_probability: f64,
     pub(crate) ib_generation_probability: f64,
@@ -482,6 +491,7 @@ impl SimConfiguration {
             praos_fallback: params.praos_fallback_enabled,
             header_diffusion_time: duration_ms(params.leios_header_diffusion_time_ms),
             relay_strategy: params.relay_strategy,
+            mempool_strategy: params.leios_mempool_sampling_strategy,
             praos_chain_quality: params.praos_chain_quality,
             block_generation_probability: params.rb_generation_probability,
             ib_generation_probability: params.ib_generation_probability,

sim-rs/sim-core/src/sim/node.rs

@@ -9,16 +9,16 @@ use std::{
 use anyhow::Result;
 use netsim_async::HasBytesSize as _;
 use priority_queue::PriorityQueue;
-use rand::Rng as _;
+use rand::{seq::SliceRandom as _, Rng as _};
 use rand_chacha::ChaChaRng;
 use tokio::{select, sync::mpsc};
 use tracing::{info, trace};
 
 use crate::{
     clock::{ClockBarrier, FutureEvent, Timestamp},
     config::{
-        DiffusionStrategy, LeiosVariant, NodeConfiguration, NodeId, RelayStrategy,
-        SimConfiguration, TransactionConfig,
+        DiffusionStrategy, LeiosVariant, MempoolSamplingStrategy, NodeConfiguration, NodeId,
+        RelayStrategy, SimConfiguration, TransactionConfig,
     },
     events::EventTracker,
     model::{
@@ -1392,7 +1392,7 @@ impl Node {
     where
         C: Fn(&SeenTransaction) -> bool,
     {
-        let candidate_txs: Vec<_> = self
+        let mut candidate_txs: Vec<_> = self
             .leios
             .mempool
             .values()
@@ -1404,6 +1404,12 @@ impl Node {
                 }
             })
             .collect();
+        if matches!(
+            self.sim_config.mempool_strategy,
+            MempoolSamplingStrategy::Random
+        ) {
+            candidate_txs.shuffle(&mut self.rng);
+        }
         let mut txs = vec![];
         let mut size = 0;
         for (id, bytes) in candidate_txs {