From 0da287d93572a438ce76bad68be6f811b3c5c979 Mon Sep 17 00:00:00 2001
From: Islam El-Ashi <islam.elashi@dfinity.org>
Date: Wed, 17 Apr 2024 15:10:29 +0200
Subject: [PATCH] chore: reduce instructions limit from 4B to 2B

---
 canister/src/heartbeat.rs | 4 ++--
 canister/src/tests.rs     | 2 +-
 canister/src/utxo_set.rs  | 5 +++--
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/canister/src/heartbeat.rs b/canister/src/heartbeat.rs
index 86dc55ff..54cb152c 100644
--- a/canister/src/heartbeat.rs
+++ b/canister/src/heartbeat.rs
@@ -391,7 +391,7 @@ mod test {
 
         // Set a large step for the performance_counter to exceed the instructions limit quickly.
         // This value allows ingesting 3 inputs/outputs per round.
-        runtime::set_performance_counter_step(1_000_000_000);
+        runtime::set_performance_counter_step(500_000_000);
 
         // Fetch blocks.
         heartbeat().await;
@@ -508,7 +508,7 @@ mod test {
 
         // Set a large step for the performance_counter to exceed the instructions limit quickly.
         // This value allows ingesting 3 transactions inputs/outputs per round.
-        runtime::set_performance_counter_step(1_000_000_000);
+        runtime::set_performance_counter_step(500_000_000);
 
         // Fetch blocks.
         heartbeat().await;
diff --git a/canister/src/tests.rs b/canister/src/tests.rs
index 32cfe159..195b7019 100644
--- a/canister/src/tests.rs
+++ b/canister/src/tests.rs
@@ -461,7 +461,7 @@ async fn time_slices_large_block_with_multiple_transactions() {
 
     // Set a large step for the performance_counter to exceed the instructions limit quickly.
     // This value allows ingesting 2 transactions inputs/outputs per round.
-    runtime::set_performance_counter_step(1_500_000_000);
+    runtime::set_performance_counter_step(750_000_000);
 
     // Fetch blocks.
     heartbeat().await;
diff --git a/canister/src/utxo_set.rs b/canister/src/utxo_set.rs
index b0b1e4c8..48949de3 100644
--- a/canister/src/utxo_set.rs
+++ b/canister/src/utxo_set.rs
@@ -555,8 +555,9 @@ impl PartialEq for UtxoSet {
 // Checks that we're not approaching the instructions limit.
 fn default_should_time_slice() -> Box<dyn FnMut() -> bool> {
     // The threshold at which time slicing kicks in.
-    // At the time of this writing it is equivalent to 80% of the maximum instructions limit.
-    const MAX_INSTRUCTIONS_THRESHOLD: u64 = 4_000_000_000;
+    // At the time of this writing it is equivalent to 40% of the maximum instructions limit.
+    // NOTE: We've reduced this limit from 4B to 2B in an effort to keep the FR stable.
+    const MAX_INSTRUCTIONS_THRESHOLD: u64 = 2_000_000_000;
 
     // NOTE: We're using `inc_performance_counter` here to also increment the mock performance
     // counter in the unit tests.