Allow displaying time-based CPU usage (#47)

* Allow time-based CPU usage

src/absim.hpp

@@ -800,14 +800,24 @@ struct arduboy_t
     std::array<uint64_t, NUM_INSTRS> profiler_counts;
     uint64_t profiler_total;
     uint64_t profiler_total_with_sleep;
+
     // counts for previous frame
     uint64_t prev_profiler_total;
     uint64_t prev_profiler_total_with_sleep;
     uint64_t prev_frame_cycles;
     uint32_t total_frames;
+    uint32_t total_ms;
     uint32_t frame_bytes_total;
     uint32_t frame_bytes;
     std::vector<float> frame_cpu_usage;
+
+    // time-based cpu usage
+    std::vector<float> ms_cpu_usage_raw;
+    std::vector<float> ms_cpu_usage;
+    uint64_t prev_profiler_total_ms;
+    uint64_t prev_profiler_total_with_sleep_ms;
+    uint64_t prev_ms_cycles;
+
     bool profiler_enabled;
 
     uint64_t cached_profiler_total;

src/absim_arduboy.cpp

@@ -112,12 +112,18 @@ void arduboy_t::reset()
     profiler_reset();
     frame_cpu_usage.clear();
     total_frames = 0;
+    total_ms = 0;
     cpu.reset();
     display.reset();
     fx.reset();
     paused = false;
     break_step = 0xffffffff;
 
+    prev_profiler_total = 0;
+    prev_profiler_total_with_sleep = 0;
+    prev_ms_cycles = 0;
+    ms_cpu_usage.clear();
+
     if(breakpoints.test(0))
         paused = true;
 }
@@ -464,6 +470,38 @@ ARDENS_FORCEINLINE uint32_t arduboy_t::cycle()
         }
     }
 
+    // time-based cpu usage
+    if(cpu.cycle_count >= prev_ms_cycles)
+    {
+        constexpr size_t MS_PROF_FILT_NUM = 5;
+        constexpr uint64_t PROF_MS = 1000000000ull * 20 / CYCLE_PS;
+        prev_ms_cycles += PROF_MS;
+
+        // one millisecond has passed: store cpu usage
+        uint64_t ms_total = profiler_total - prev_profiler_total_ms;
+        uint64_t ms_sleep = profiler_total_with_sleep - prev_profiler_total_with_sleep_ms;
+        prev_profiler_total_ms = profiler_total;
+        prev_profiler_total_with_sleep_ms = profiler_total_with_sleep;
+        double f = ms_sleep ? double(ms_total) / double(ms_sleep) : 0.0;
+        ms_cpu_usage_raw.push_back((float)f);
+        if(ms_cpu_usage_raw.size() >= MS_PROF_FILT_NUM)
+        {
+            float t = 0.f;
+            for(size_t i = 0; i < MS_PROF_FILT_NUM; ++i)
+                t += ms_cpu_usage_raw[ms_cpu_usage_raw.size() - MS_PROF_FILT_NUM + i];
+            ms_cpu_usage.push_back(t * (1.f / MS_PROF_FILT_NUM));
+        }
+        ++total_ms;
+
+        // limit memory usage
+        if(ms_cpu_usage.size() >= 65536)
+        {
+            ms_cpu_usage.erase(
+                ms_cpu_usage.begin(),
+                ms_cpu_usage.begin() + 32768);
+        }
+    }
+
     return cycles;
 }
 

src/absim_snapshot.cpp

@@ -240,9 +240,12 @@ static std::string serdes_snapshot(Archive& ar, arduboy_t& a)
     ar(a.profiler_total_with_sleep);
     ar(a.prev_frame_cycles);
     ar(a.total_frames);
+    ar(a.prev_ms_cycles);
+    ar(a.total_ms);
     ar(a.frame_bytes_total);
     ar(a.frame_bytes);
     ar(a.frame_cpu_usage);
+    ar(a.ms_cpu_usage);
     ar(a.profiler_enabled);
     ar(a.cached_profiler_total);
     ar(a.cached_profiler_total_with_sleep);

src/settings.cpp

@@ -55,6 +55,7 @@ static void settings_read_line(
     ARDENS_BOOL_SETTING(record_wav);
     ARDENS_BOOL_SETTING(recording_sameasdisplay);
     ARDENS_BOOL_SETTING(nondeterminism);
+    ARDENS_BOOL_SETTING(frame_based_cpu_usage);
 
     ARDENS_BOOL_SETTING(ab.stack_overflow);
     ARDENS_BOOL_SETTING(ab.null_deref);
@@ -125,6 +126,7 @@ static void settings_write_all(ImGuiContext* ctx, ImGuiSettingsHandler* handler,
     ARDENS_BOOL_SETTING(record_wav);
     ARDENS_BOOL_SETTING(recording_sameasdisplay);
     ARDENS_BOOL_SETTING(nondeterminism);
+    ARDENS_BOOL_SETTING(frame_based_cpu_usage);
 
     ARDENS_BOOL_SETTING(ab.stack_overflow);
     ARDENS_BOOL_SETTING(ab.null_deref);

src/settings.hpp

@@ -56,6 +56,7 @@ struct settings_t
     bool profiler_group_symbols = false;
     bool enable_step_breaks = true;
     bool nondeterminism = false;
+    bool frame_based_cpu_usage = true;
 
     struct
     {

src/window_cpu_usage.cpp

@@ -8,6 +8,12 @@
 
 extern std::unique_ptr<absim::arduboy_t> arduboy;
 
+static int xaxis_ms_formatter(double value, char* buf, int size, void* user)
+{
+    (void)user;
+    return snprintf(buf, (size_t)size, "%.1f", value * 0.02);
+}
+
 static int yaxis_formatter(double value, char* buf, int size, void* user)
 {
     (void)user;
@@ -18,21 +24,29 @@ static void window_contents()
 {
     using namespace ImPlot;
 
-    if(arduboy->frame_cpu_usage.empty())
+    bool& frame_based = settings.frame_based_cpu_usage;
+
+    if(!arduboy)
+        return;
+    if(!frame_based && arduboy->ms_cpu_usage.empty() ||
+        frame_based && arduboy->frame_cpu_usage.empty())
         return;
 
     {
         float usage = 0.f;
         size_t i;
-        for(i = 0; i < 16; ++i)
+        size_t n = frame_based ? 16 : 3;
+        auto const& d = frame_based ? arduboy->frame_cpu_usage : arduboy->ms_cpu_usage;
+        for(i = 0; i < n; ++i)
         {
-            if(i >= arduboy->frame_cpu_usage.size())
+            if(i >= d.size())
                 break;
-            usage += arduboy->frame_cpu_usage[arduboy->frame_cpu_usage.size() - i - 1];
+            usage += d[d.size() - i - 1];
         }
-        usage /= i;
-        bool red = arduboy->frame_cpu_usage.back() > 0.999;
+        usage /= n;
+        bool red = usage > 0.999f;
         if(red) ImGui::PushStyleColor(ImGuiCol_Text, IM_COL32(255, 0, 0, 255));
+        ImGui::AlignTextToFramePadding();
         ImGui::Text("CPU Usage: %5.1f%%", usage * 100);
         if(red) ImGui::PopStyleColor();
     }
@@ -46,9 +60,13 @@ static void window_contents()
         fps_i = (fps_i + 1) % fps_queue.size();
         fps = std::accumulate(fps_queue.begin(), fps_queue.end(), 0.f) * (1.f / fps_queue.size());
         ImGui::SameLine();
-        ImGui::Text("     FPS: %5.1f", fps);
+        ImGui::AlignTextToFramePadding();
+        ImGui::Text("     FPS: %5.1f     ", fps);
     }
 
+    ImGui::SameLine();
+    ImGui::Checkbox("Align to frames", &frame_based);
+
     constexpr auto plot_flags =
         ImPlotFlags_NoTitle |
         ImPlotFlags_NoLegend |
@@ -61,8 +79,9 @@ static void window_contents()
         auto* plot = GetCurrentPlot();
         constexpr double ZOOM = 4.0;
         constexpr double IZOOM = 1.0 / ZOOM;
-        double n = double(arduboy->total_frames);
-        double m = n - arduboy->frame_cpu_usage.size();
+        double n = double(frame_based? arduboy->total_frames : arduboy->total_ms);
+        auto const& d = frame_based ? arduboy->frame_cpu_usage : arduboy->ms_cpu_usage;
+        double m = n - d.size();
         double w = plot->FrameRect.GetWidth();
 
         double z = plot->Axes[ImAxis_X1].Range.Size();
@@ -74,8 +93,10 @@ static void window_contents()
             ImPlotAxisFlags_NoHighlight |
             //ImPlotAxisFlags_NoDecorations |
             0;
-        SetupAxis(ImAxis_X1, "Frame", axis_flags);
+        SetupAxis(ImAxis_X1, frame_based ? "Frame" : "Time (s)", axis_flags);
         SetupAxis(ImAxis_Y1, nullptr, axis_flags);
+        if(!frame_based)
+            SetupAxisFormat(ImAxis_X1, xaxis_ms_formatter);
         SetupAxisFormat(ImAxis_Y1, yaxis_formatter);
 
         double lim_min = m;
@@ -103,13 +124,13 @@ static void window_contents()
         SetupFinish();
         PushStyleVar(ImPlotStyleVar_FillAlpha, 0.25f);
         PlotShaded("##usage",
-            arduboy->frame_cpu_usage.data(),
-            (int)arduboy->frame_cpu_usage.size(),
+            d.data(),
+            (int)d.size(),
             0.0, 1.0, m);
         PopStyleVar();
         PlotLine("##usage",
-            arduboy->frame_cpu_usage.data(),
-            (int)arduboy->frame_cpu_usage.size(),
+            d.data(),
+            (int)d.size(),
             1.0, m);
         EndPlot();
     }