From c8dfaa5f8d93649acf193d7c89a2a63e5be39690 Mon Sep 17 00:00:00 2001
From: Michael Fazio <michaelfazio@me.com>
Date: Tue, 28 Jan 2020 22:22:12 +0800
Subject: [PATCH] Use parallel unstable sort of nodes in Vicinity layer

---
 Cargo.toml                 | 1 +
 src/poldercast/vicinity.rs | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 763ea7d..6fce6bf 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,7 @@ rand = "0.7"
 hex = "0.4"
 serde = { version = "1.0", features = ["derive"] }
 thiserror = "1.0"
+rayon = "1.3.0"
 
 [dev-dependencies]
 rand_chacha = "0.2"
diff --git a/src/poldercast/vicinity.rs b/src/poldercast/vicinity.rs
index 4d9baf4..7616a47 100644
--- a/src/poldercast/vicinity.rs
+++ b/src/poldercast/vicinity.rs
@@ -1,4 +1,5 @@
 use crate::{GossipsBuilder, Id, Layer, Node, NodeProfile, Nodes, ViewBuilder};
+use rayon::prelude::*;
 
 const VICINITY_MAX_VIEW_SIZE: usize = 20;
 const VICINITY_MAX_GOSSIP_LENGTH: usize = 10;
@@ -75,7 +76,8 @@ impl Vicinity {
         mut profiles: Vec<&Node>,
         max: usize,
     ) -> Vec<Id> {
-        profiles.sort_by(|left, right| {
+        // Use unstable parallel sort as total number of nodes can be quite large.
+        profiles.par_sort_unstable_by(|left, right| {
             to.proximity(left.profile())
                 .cmp(&to.proximity(right.profile()))
         });