From 6ceacc14ae3cc115939028f75cf53c90d5e057a4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Piotr=20Wo=CC=81jcik?=
 <3044353+pwojcikdev@users.noreply.github.com>
Date: Wed, 8 Nov 2023 00:14:36 +0100
Subject: [PATCH] Ignore AEC vacancy notification for hinted scheduler

---
 nano/core_test/toml.cpp        |  2 --
 nano/node/scheduler/hinted.cpp | 15 ++-------------
 nano/node/scheduler/hinted.hpp |  1 -
 3 files changed, 2 insertions(+), 16 deletions(-)

diff --git a/nano/core_test/toml.cpp b/nano/core_test/toml.cpp
index 744e70acd8..8adb17d82e 100644
--- a/nano/core_test/toml.cpp
+++ b/nano/core_test/toml.cpp
@@ -275,7 +275,6 @@ TEST (toml, daemon_config_deserialize_defaults)
 	ASSERT_EQ (conf.node.hinted_scheduler.hinting_threshold_percent, defaults.node.hinted_scheduler.hinting_threshold_percent);
 	ASSERT_EQ (conf.node.hinted_scheduler.check_interval.count (), defaults.node.hinted_scheduler.check_interval.count ());
 	ASSERT_EQ (conf.node.hinted_scheduler.block_cooldown.count (), defaults.node.hinted_scheduler.block_cooldown.count ());
-	ASSERT_EQ (conf.node.hinted_scheduler.vacancy_threshold_percent, defaults.node.hinted_scheduler.vacancy_threshold_percent);
 
 	ASSERT_EQ (conf.node.vote_cache.max_size, defaults.node.vote_cache.max_size);
 	ASSERT_EQ (conf.node.vote_cache.max_voters, defaults.node.vote_cache.max_voters);
@@ -722,7 +721,6 @@ TEST (toml, daemon_config_deserialize_no_defaults)
 	ASSERT_NE (conf.node.hinted_scheduler.hinting_threshold_percent, defaults.node.hinted_scheduler.hinting_threshold_percent);
 	ASSERT_NE (conf.node.hinted_scheduler.check_interval.count (), defaults.node.hinted_scheduler.check_interval.count ());
 	ASSERT_NE (conf.node.hinted_scheduler.block_cooldown.count (), defaults.node.hinted_scheduler.block_cooldown.count ());
-	ASSERT_NE (conf.node.hinted_scheduler.vacancy_threshold_percent, defaults.node.hinted_scheduler.vacancy_threshold_percent);
 
 	ASSERT_NE (conf.node.vote_cache.max_size, defaults.node.vote_cache.max_size);
 	ASSERT_NE (conf.node.vote_cache.max_voters, defaults.node.vote_cache.max_voters);
diff --git a/nano/node/scheduler/hinted.cpp b/nano/node/scheduler/hinted.cpp
index 6bbaff7de9..833e59f929 100644
--- a/nano/node/scheduler/hinted.cpp
+++ b/nano/node/scheduler/hinted.cpp
@@ -45,12 +45,8 @@ void nano::scheduler::hinted::stop ()
 
 void nano::scheduler::hinted::notify ()
 {
-	// Avoid notifying when there is very little space inside AEC
-	auto const limit = active.limit (nano::election_behavior::hinted);
-	if (active.vacancy (nano::election_behavior::hinted) >= (limit * config.vacancy_threshold_percent / 100))
-	{
-		condition.notify_all ();
-	}
+	// Ignore vacancy notifications, since they are causing (expensive) vote cache iteration to run too often
+	// TODO: Research a better way to handle this
 }
 
 bool nano::scheduler::hinted::predicate () const
@@ -230,7 +226,6 @@ nano::error nano::scheduler::hinted_config::serialize (nano::tomlconfig & toml)
 	toml.put ("hinting_threshold", hinting_threshold_percent, "Percentage of online weight needed to start a hinted election. \ntype:uint32,[0,100]");
 	toml.put ("check_interval", check_interval.count (), "Interval between scans of the vote cache for possible hinted elections. \ntype:milliseconds");
 	toml.put ("block_cooldown", block_cooldown.count (), "Cooldown period for blocks that failed to start an election. \ntype:milliseconds");
-	toml.put ("vacancy_threshold", vacancy_threshold_percent, "Percentage of available space in the active elections container needed to trigger a scan for hinted elections (before the check interval elapses). \ntype:uint32,[0,100]");
 
 	return toml.get_error ();
 }
@@ -247,16 +242,10 @@ nano::error nano::scheduler::hinted_config::deserialize (nano::tomlconfig & toml
 	toml.get ("block_cooldown", block_cooldown_l);
 	block_cooldown = std::chrono::milliseconds{ block_cooldown_l };
 
-	toml.get ("vacancy_threshold", vacancy_threshold_percent);
-
 	if (hinting_threshold_percent > 100)
 	{
 		toml.get_error ().set ("hinting_threshold must be a number between 0 and 100");
 	}
-	if (vacancy_threshold_percent > 100)
-	{
-		toml.get_error ().set ("vacancy_threshold must be a number between 0 and 100");
-	}
 
 	return toml.get_error ();
 }
\ No newline at end of file
diff --git a/nano/node/scheduler/hinted.hpp b/nano/node/scheduler/hinted.hpp
index a80bb68c05..f907e21175 100644
--- a/nano/node/scheduler/hinted.hpp
+++ b/nano/node/scheduler/hinted.hpp
@@ -39,7 +39,6 @@ class hinted_config final
 	std::chrono::milliseconds check_interval{ 1000 };
 	std::chrono::milliseconds block_cooldown{ 10000 };
 	unsigned hinting_threshold_percent{ 10 };
-	unsigned vacancy_threshold_percent{ 20 };
 };
 
 /*