From 11a0c40cd7da06f57639e8f881829b2fc6427b6f Mon Sep 17 00:00:00 2001
From: dr-frmr <docterformer@protonmail.com>
Date: Thu, 16 Nov 2023 12:27:16 -0500
Subject: [PATCH] timer -> millisecond granularity

---
 Cargo.lock   |  7 +++++++
 Cargo.toml   |  1 +
 src/timer.rs | 30 ++++++++++--------------------
 3 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index aeede84c..8f39d09a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2921,6 +2921,12 @@ version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
 
+[[package]]
+name = "nohash-hasher"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2bf50223579dc7cdcfb3bfcacf7069ff68243f8c363f62ffa99cf000a6b9c451"
+
 [[package]]
 name = "num-bigint"
 version = "0.4.4"
@@ -5113,6 +5119,7 @@ dependencies = [
  "jwt",
  "lazy_static",
  "log",
+ "nohash-hasher",
  "num-traits",
  "open",
  "public-ip",
diff --git a/Cargo.toml b/Cargo.toml
index 7c947b7e..07be5539 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -41,6 +41,7 @@ http = "0.2.9"
 jwt = "0.16"
 lazy_static = "1.4.0"
 log = "*"
+nohash-hasher = "0.2.0"
 num-traits = "0.2"
 open = "5.0.0"
 public-ip = "0.2.2"
diff --git a/src/timer.rs b/src/timer.rs
index 81efaf26..cdd7cefd 100644
--- a/src/timer.rs
+++ b/src/timer.rs
@@ -4,7 +4,6 @@ use crate::types::{
 };
 use anyhow::Result;
 use serde::{Deserialize, Serialize};
-use std::collections::BTreeMap;
 
 /// A runtime module that allows processes to set timers. Interacting with the
 /// timer is done with a simple Request/Response pattern, and the timer module
@@ -13,7 +12,7 @@ use std::collections::BTreeMap;
 ///
 /// The interface of the timer module is as follows:
 /// One kind of request is accepted: the IPC must be a little-endian byte-representation
-/// of an unsigned 64-bit integer, in seconds. This request should always expect a Response.
+/// of an unsigned 64-bit integer, in milliseconds. This request should always expect a Response.
 /// If the request does not expect a Response, the timer will not be set.
 ///
 /// A proper Request will trigger the timer module to send a Response. The Response will be
@@ -28,7 +27,7 @@ pub async fn timer_service(
 ) -> Result<()> {
     // if we have a persisted state file, load it
     let mut timer_map = TimerMap {
-        timers: BTreeMap::new(),
+        timers: nohash_hasher::IntMap::default(),
     };
     // joinset holds 1 active timer per expiration-time
     let mut timer_tasks = tokio::task::JoinSet::<u64>::new();
@@ -54,22 +53,22 @@ pub async fn timer_service(
                     continue
                 }
                 let Ok(bytes): Result<[u8; 8], _> = req.ipc.try_into() else { continue };
-                let timer_secs = u64::from_le_bytes(bytes);
-                // if the timer is set to pop in 0 seconds, we immediately respond
+                let timer_millis = u64::from_le_bytes(bytes);
+                // if the timer is set to pop in 0 millis, we immediately respond
                 // otherwise, store in our persisted map, and spawn a task that
                 // sleeps for the given time, then sends the response
                 let now = std::time::SystemTime::now()
                     .duration_since(std::time::UNIX_EPOCH)
                     .unwrap()
-                    .as_secs();
-                let pop_time = now + timer_secs;
-                if timer_secs == 0 {
+                    .as_millis() as u64;
+                let pop_time = now + timer_millis;
+                if timer_millis == 0 {
                     send_response(&our, km.id, km.rsvp.unwrap_or(km.source), &kernel_message_sender).await;
                     continue
                 }
                 if !timer_map.contains(pop_time) {
                     timer_tasks.spawn(async move {
-                        tokio::time::sleep(std::time::Duration::from_secs(timer_secs)).await;
+                        tokio::time::sleep(std::time::Duration::from_millis(timer_millis - 1)).await;
                         return pop_time
                     });
                 }
@@ -89,10 +88,10 @@ pub async fn timer_service(
 
 #[derive(Serialize, Deserialize, Debug)]
 struct TimerMap {
-    // key: the unix timestamp at which the timer pops
+    // key: the unix timestamp in milliseconds at which the timer pops
     // value: a vector of KernelMessage ids and who to send Response to
     // this is because multiple processes can set timers for the same time
-    timers: BTreeMap<u64, Vec<(u64, Address)>>,
+    timers: nohash_hasher::IntMap<u64, Vec<(u64, Address)>>,
 }
 
 impl TimerMap {
@@ -110,15 +109,6 @@ impl TimerMap {
     fn remove(&mut self, pop_time: u64) -> Option<Vec<(u64, Address)>> {
         self.timers.remove(&pop_time)
     }
-
-    fn _drain_expired(&mut self, time: u64) -> Vec<(u64, Address)> {
-        return self
-            .timers
-            .extract_if(|k, _| *k <= time)
-            .map(|(_, v)| v)
-            .flatten()
-            .collect();
-    }
 }
 
 async fn send_response(our_node: &str, id: u64, target: Address, send_to_loop: &MessageSender) {