core_timing: Remove GetCurrentTimerResolution in CoreTiming loop

Other programs may change this value, but if thousands of syscalls in this loop is undesirable, then we can just set this once.

2 files changed, 14 insertions, 3 deletions

diff --git a/src/core/core_timing.cpp b/src/core/core_timing.cpp
index 4f0a3f8ea..e6112a3c9 100644
--- a/src/core/core_timing.cpp
+++ b/src/core/core_timing.cpp
@@ -253,9 +253,6 @@ void CoreTiming::ThreadLoop() {
                 auto wait_time = *next_time - GetGlobalTimeNs().count();
                 if (wait_time > 0) {
 #ifdef _WIN32
-                    const auto timer_resolution_ns =
-                        Common::Windows::GetCurrentTimerResolution().count();
-
                     while (!paused && !event.IsSet() && wait_time > 0) {
                         wait_time = *next_time - GetGlobalTimeNs().count();
 
@@ -316,4 +313,10 @@ std::chrono::microseconds CoreTiming::GetGlobalTimeUs() const {
     return std::chrono::microseconds{Common::WallClock::CPUTickToUS(cpu_ticks)};
 }
 
+#ifdef _WIN32
+void CoreTiming::SetTimerResolutionNs(std::chrono::nanoseconds ns) {
+    timer_resolution_ns = ns.count();
+}
+#endif
+
 } // namespace Core::Timing
diff --git a/src/core/core_timing.h b/src/core/core_timing.h
index 10db1de55..5bca1c78d 100644
--- a/src/core/core_timing.h
+++ b/src/core/core_timing.h
@@ -131,6 +131,10 @@ public:
     /// Checks for events manually and returns time in nanoseconds for next event, threadsafe.
     std::optional<s64> Advance();
 
+#ifdef _WIN32
+    void SetTimerResolutionNs(std::chrono::nanoseconds ns);
+#endif
+
 private:
     struct Event;
 
@@ -143,6 +147,10 @@ private:
 
     s64 global_timer = 0;
 
+#ifdef _WIN32
+    s64 timer_resolution_ns;
+#endif
+
     // The queue is a min-heap using std::make_heap/push_heap/pop_heap.
     // We don't use std::priority_queue because we need to be able to serialize, unserialize and
     // erase arbitrary events (RemoveEvent()) regardless of the queue order. These aren't