From c06551329f012a36d1b810f777e6f0f6b3b72795 Mon Sep 17 00:00:00 2001
From: Dennis Kobert <dennis@kobert.dev>
Date: Tue, 1 Apr 2025 00:19:03 +0200
Subject: Alloc empty Task info structs on extra thread

---
 src/scheduler.rs | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

(limited to 'src')

diff --git a/src/scheduler.rs b/src/scheduler.rs
index a936b3c..412d00e 100644
--- a/src/scheduler.rs
+++ b/src/scheduler.rs
@@ -40,6 +40,7 @@ pub struct Scheduler<'a> {
     to_remove: Vec<Pid>,
     e_core_selector: Box<dyn ECoreSelector>,
     energy_sender: mpsc::SyncSender<EnergyRequest>,
+    empty_task_infos: mpsc::Receiver<Arc<TaskInfo>>,
     frequency_sender: mpsc::SyncSender<FrequencyRequest>,
     shared_cpu_frequency_ranges: Arc<RwLock<Vec<RangeInclusive<FrequencyKHZ>>>>,
     shared_policy_frequency_ranges: Arc<RwLock<Vec<RangeInclusive<FrequencyKHZ>>>>,
@@ -52,13 +53,6 @@ impl<'a> Scheduler<'a> {
         use_mocking: bool,
         power_cap: u64,
     ) -> Result<Self> {
-        let bpf = BpfScheduler::init(
-            open_object,
-            0,     // exit_dump_len (buffer size of exit info, 0 = default)
-            false, // partial (false = include all tasks)
-            false, // debug (false = debug mode off)
-        )?;
-
         println!("Initializing energy-aware scheduler");
 
         let shared_cpu_frequency_ranges: Arc<RwLock<Vec<RangeInclusive<FrequencyKHZ>>>> =
@@ -77,6 +71,11 @@ impl<'a> Scheduler<'a> {
             shared_cpu_current_frequencies.clone(),
         )?;
 
+        let (task_sender, empty_task_infos) = mpsc::sync_channel(200);
+        std::thread::spawn(move || loop {
+            task_sender.send(Arc::new(TaskInfo::default()));
+        });
+
         let topology = Topology::new().unwrap();
         let mut e_core_ids = Vec::new();
         let mut p_core_ids = Vec::new();
@@ -111,6 +110,15 @@ impl<'a> Scheduler<'a> {
             .try_send(FrequencyRequest::GetPossibleCPUFrequencyRange)
             .unwrap();
 
+        std::thread::sleep(Duration::from_secs(1));
+
+        let bpf = BpfScheduler::init(
+            open_object,
+            0,     // exit_dump_len (buffer size of exit info, 0 = default)
+            false, // partial (false = include all tasks)
+            false, // debug (false = debug mode off)
+        )?;
+
         Ok(Self {
             bpf,
             task_queue: VecDeque::new(),
@@ -119,6 +127,7 @@ impl<'a> Scheduler<'a> {
             maximum_budget: u64::MAX,
             own_pid: process::id() as i32,
             p_cores,
+            empty_task_infos,
             tasks_scheduled: 0,
             e_cores,
             topology,
@@ -164,11 +173,9 @@ impl<'a> Scheduler<'a> {
                 std::collections::hash_map::Entry::Vacant(e) => {
                     let is_e_core = self.e_cores.contains(&task.cpu);
                     // New task - register it with the energy service
-                    let task_info = Arc::new(TaskInfo {
-                        cpu: AtomicI32::new(task.cpu),
-                        running_on_e_core: AtomicBool::new(is_e_core),
-                        ..Default::default()
-                    });
+                    let task_info = self.empty_task_infos.recv().unwrap();
+                    task_info.set_cpu(task.cpu);
+                    task_info.set_running_on_e_core(is_e_core);
                     e.insert(Task {
                         task_info: task_info.clone(),
                         last_scheduled: Instant::now(),
-- 
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