From b861f0457ba52c027384b14f20585166feddd3fe Mon Sep 17 00:00:00 2001
From: Baber Nawaz <baber.nawaz@reactivemarkets.com>
Date: Mon, 1 Dec 2025 15:17:49 +0000
Subject: [PATCH] chore: Using Mono clock for Reactor time thresholds

SDB-10154
---
 toolbox/io/Reactor.cpp    | 13 +++++++------
 toolbox/io/Reactor.hpp    |  8 ++++----
 toolbox/io/Reactor.ut.cpp | 18 +++++++++---------
 3 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/toolbox/io/Reactor.cpp b/toolbox/io/Reactor.cpp
index 1c1d943f..9c56c6b7 100644
--- a/toolbox/io/Reactor.cpp
+++ b/toolbox/io/Reactor.cpp
@@ -97,7 +97,8 @@ int Reactor::poll(CyclTime now, Duration timeout)
     }
     // Update cycle time after epoll() returns.
     now = CyclTime::now();
-    last_time_priority_io_polled_ = now.wall_time();
+    last_time_priority_io_polled_ = now.mono_time();
+    last_time_user_hook_polled_ = now.mono_time();
 
     if (ec) {
         if (ec.value() != EINTR) {
@@ -157,12 +158,12 @@ void Reactor::yield() noexcept
         return;
     }
 
-    WallTime now = WallClock::now();
+    MonoTime now = MonoClock::now();
     cycle_work_ += do_io_priority_poll(now);
     cycle_work_ += do_user_priority_poll(now);
 }
 
-int Reactor::do_io_priority_poll(WallTime now) noexcept
+int Reactor::do_io_priority_poll(MonoTime now) noexcept
 {
     int ret = 0;
     try {
@@ -172,7 +173,7 @@ int Reactor::do_io_priority_poll(WallTime now) noexcept
 
         if (enabled && breached) {
             const auto update_poll_time = make_finally([this]() noexcept {
-                last_time_priority_io_polled_ = WallClock::now();
+                last_time_priority_io_polled_ = MonoClock::now();
             });
 
             error_code ec;
@@ -195,7 +196,7 @@ int Reactor::do_io_priority_poll(WallTime now) noexcept
     return ret;
 }
 
-int Reactor::do_user_priority_poll(WallTime now) noexcept
+int Reactor::do_user_priority_poll(MonoTime now) noexcept
 {
     int ret = 0;
     try {
@@ -206,7 +207,7 @@ int Reactor::do_user_priority_poll(WallTime now) noexcept
 
         if (enabled && breached) {
             const auto update_poll_time = make_finally([this]() noexcept {
-                last_time_user_hook_polled_ = WallClock::now();
+                last_time_user_hook_polled_ = MonoClock::now();
             });
 
             currently_handling_priority_events_ = true;
diff --git a/toolbox/io/Reactor.hpp b/toolbox/io/Reactor.hpp
index ee3176a1..8c4ad3ef 100644
--- a/toolbox/io/Reactor.hpp
+++ b/toolbox/io/Reactor.hpp
@@ -195,8 +195,8 @@ class TOOLBOX_API Reactor : public Waker {
     void set_events(int fd, int sid, unsigned events);
     void unsubscribe(int fd, int sid) noexcept;
     void set_io_priority(int fd, int sid, Priority priority) noexcept;
-    int do_io_priority_poll(WallTime now) noexcept;
-    int do_user_priority_poll(WallTime now) noexcept;
+    int do_io_priority_poll(MonoTime now) noexcept;
+    int do_user_priority_poll(MonoTime now) noexcept;
 
     struct Data {
         int sid{};
@@ -215,8 +215,8 @@ class TOOLBOX_API Reactor : public Waker {
     HookList end_of_cycle_no_wait_hooks, end_of_event_dispatch_hooks_;
     Micros priority_io_poll_threshold_ = Micros::max();
     Micros user_hook_poll_threshold_ = Micros::max();
-    WallTime last_time_priority_io_polled_{};
-    WallTime last_time_user_hook_polled_{};
+    MonoTime last_time_priority_io_polled_{};
+    MonoTime last_time_user_hook_polled_{};
     PollSlot priority_poll_user_hook_;
     int cycle_work_{0};
     bool currently_handling_priority_events_{false};
diff --git a/toolbox/io/Reactor.ut.cpp b/toolbox/io/Reactor.ut.cpp
index 760dccdd..58a00d4d 100644
--- a/toolbox/io/Reactor.ut.cpp
+++ b/toolbox/io/Reactor.ut.cpp
@@ -153,16 +153,16 @@ BOOST_AUTO_TEST_CASE(ReactorHighPriorityHook)
 
     auto [s1, s2] = socketpair(UnixStreamProtocol{});
 
-    // This is handler for data on s1. It is an expensive function taking ~100ms
+    // This is handler for data on s1. It is an expensive function taking ~250ms
     std::size_t yield_count = 0;
     auto on_data_received = [&](CyclTime, int, unsigned) {
-        WallTime now = WallClock::now();
-        WallTime end = now + 500ms;
+        MonoTime now = MonoClock::now();
+        MonoTime end = now + 250ms;
         while (now < end) {
-            // wait for 100us, then yield
-            auto next_stop = now + 1ms;
+            // wait for 1ms, then yield
+            auto next_stop = MonoClock::now() + 1ms;
             while (now < next_stop) {
-                now = WallClock::now();
+                now = MonoClock::now();
             }
             r.yield();
             yield_count++;
@@ -211,13 +211,13 @@ BOOST_AUTO_TEST_CASE(ReactorHighPriorityYield)
 
     // each invocation will take ~100ms
     auto spin_and_yield_periodically = [&r]() {
-        WallTime now = WallClock::now();
-        WallTime end = now + 100ms;
+        MonoTime now = MonoClock::now();
+        MonoTime end = now + 100ms;
         while (now < end) {
             // wait for 10us, then yield
             auto next_stop = now + 10us;
             while (now < next_stop) {
-                now = WallClock::now();
+                now = MonoClock::now();
             }
             r.yield();
         };