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-rw-r--r--src/common/profiler.cpp23
-rw-r--r--src/common/profiler.h20
2 files changed, 42 insertions, 1 deletions
diff --git a/src/common/profiler.cpp b/src/common/profiler.cpp
index c37546af0..65c3df167 100644
--- a/src/common/profiler.cpp
+++ b/src/common/profiler.cpp
@@ -6,6 +6,12 @@
#include "common/profiler_reporting.h"
#include "common/assert.h"
+#if defined(_MSC_VER) && _MSC_VER <= 1800 // MSVC 2013.
+#define NOMINMAX
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h> // For QueryPerformanceCounter/Frequency
+#endif
+
namespace Common {
namespace Profiling {
@@ -13,6 +19,23 @@ namespace Profiling {
thread_local Timer* Timer::current_timer = nullptr;
#endif
+#if defined(_MSC_VER) && _MSC_VER <= 1800 // MSVC 2013
+QPCClock::time_point QPCClock::now() {
+ static LARGE_INTEGER freq;
+ // Use this dummy local static to ensure this gets initialized once.
+ static BOOL dummy = QueryPerformanceFrequency(&freq);
+
+ LARGE_INTEGER ticks;
+ QueryPerformanceCounter(&ticks);
+
+ // This is prone to overflow when multiplying, which is why I'm using micro instead of nano. The
+ // correct way to approach this would be to just return ticks as a time_point and then subtract
+ // and do this conversion when creating a duration from two time_points, however, as far as I
+ // could tell the C++ requirements for these types are incompatible with this approach.
+ return time_point(duration(ticks.QuadPart * std::micro::den / freq.QuadPart));
+}
+#endif
+
TimingCategory::TimingCategory(const char* name, TimingCategory* parent)
: accumulated_duration(0) {
diff --git a/src/common/profiler.h b/src/common/profiler.h
index 53c4f6eaf..3e967b4bc 100644
--- a/src/common/profiler.h
+++ b/src/common/profiler.h
@@ -18,8 +18,26 @@ namespace Profiling {
#define ENABLE_PROFILING 1
#endif
-using Duration = std::chrono::nanoseconds;
+#if defined(_MSC_VER) && _MSC_VER <= 1800 // MSVC 2013
+// MSVC up to 2013 doesn't use QueryPerformanceCounter for high_resolution_clock, so it has bad
+// precision. We manually implement a clock based on QPC to get good results.
+
+struct QPCClock {
+ using duration = std::chrono::microseconds;
+ using time_point = std::chrono::time_point<QPCClock>;
+ using rep = duration::rep;
+ using period = duration::period;
+ static const bool is_steady = false;
+
+ static time_point now();
+};
+
+using Clock = QPCClock;
+#else
using Clock = std::chrono::high_resolution_clock;
+#endif
+
+using Duration = Clock::duration;
/**
* Represents a timing category that measured time can be accounted towards. Should be declared as a