Add I/O stats

Using /proc/self/io 'read_bytes' and 'write_bytes' fields which count only
reads/writes that hit the storage (i.e no cached reads).

src/iostats.cpp

@@ -0,0 +1,27 @@
+#include "iostats.h"
+#include "string_utils.h"
+#include <fstream>
+
+pthread_t ioThread;
+void *getIoStats(void *args) {
+    iostats *io = reinterpret_cast<iostats *>(args);
+    if (io) {
+        io->prev.read_bytes  = io->curr.read_bytes;
+        io->prev.write_bytes = io->curr.write_bytes;
+
+        std::string line;
+        std::ifstream f("/proc/self/io");
+        while (std::getline(f, line)) {
+            if (starts_with(line, "read_bytes:")) {
+                try_stoull(io->curr.read_bytes, line.substr(12));
+            }
+            else if (starts_with(line, "write_bytes:")) {
+                try_stoull(io->curr.write_bytes, line.substr(13));
+            }
+        }
+        io->diff.read  = (io->curr.read_bytes  - io->prev.read_bytes) / (1024.f * 1024.f);
+        io->diff.write = (io->curr.write_bytes - io->prev.write_bytes) / (1024.f * 1024.f);
+    }
+    pthread_detach(ioThread);
+    return NULL;
+}

src/iostats.h

@@ -0,0 +1,22 @@
+#pragma once
+#include <pthread.h>
+#include <inttypes.h>
+
+extern pthread_t ioThread;
+
+struct iostats {
+    struct {
+      unsigned long long read_bytes;
+      unsigned long long write_bytes;
+    } curr;
+    struct {
+      unsigned long long read_bytes;
+      unsigned long long write_bytes;
+    } prev;
+    struct {
+      float read;
+      float write;
+    } diff;
+};
+
+void *getIoStats(void *args);

src/meson.build

@@ -41,6 +41,7 @@ vklayer_files = files(
   'file_utils.cpp',
   'memory.cpp',
   'config.cpp',
+  'iostats.cpp',
 )
 
 # lib_xnvctrl = cc.find_library('XNVCtrl')

src/overlay.cpp

@@ -54,6 +54,7 @@
 #include "logging.h"
 #include "keybinds.h"
 #include "cpu.h"
+#include "iostats.h"
 #include "loaders/loader_nvml.h"
 
 bool open = false;
@@ -223,6 +224,8 @@ struct swapchain_data {
 
    /* Over fps_sampling_period */
    struct frame_stat accumulated_stats;
+
+   struct iostats io;
 };
 
 static const VkQueryPipelineStatisticFlags overlay_query_flags =
@@ -986,6 +989,7 @@ static void snapshot_swapchain_frame(struct swapchain_data *data)
 
             // get ram usage/max
             pthread_create(&memoryThread, NULL, &update_meminfo, NULL);
+            pthread_create(&ioThread, NULL, &getIoStats, &data->io);
 
             // update variables for logging
             // cpuLoadLog = cpuArray[0].value;
@@ -1212,6 +1216,26 @@ static void compute_swapchain_display(struct swapchain_data *data)
          ImGui::Text("GB");
          ImGui::PopFont();
       }
+      if (instance_data->params.io_read){
+         auto sampling = instance_data->params.fps_sampling_period;
+         ImGui::TextColored(ImVec4(0.760, 0.576, 0.4, 1.00f), "IO rd");
+         ImGui::SameLine(hudFirstRow);
+         ImGui::Text("%.2f", data->io.diff.read * (1000000 / sampling));
+         ImGui::SameLine(0,1.0f);
+         ImGui::PushFont(data->font1);
+         ImGui::Text("MiB/s");
+         ImGui::PopFont();
+      }
+      if (instance_data->params.io_write){
+         auto sampling = instance_data->params.fps_sampling_period;
+         ImGui::TextColored(ImVec4(0.760, 0.576, 0.4, 1.00f), "IO wr");
+         ImGui::SameLine(hudFirstRow);
+         ImGui::Text("%.2f", data->io.diff.write * (1000000 / sampling));
+         ImGui::SameLine(0,1.0f);
+         ImGui::PushFont(data->font1);
+         ImGui::Text("MiB/s");
+         ImGui::PopFont();
+      }
       if (instance_data->params.enabled[OVERLAY_PARAM_ENABLED_fps]){
          ImGui::TableNextRow();
          ImGui::TextColored(ImVec4(0.925, 0.411, 0.411, 1.00f), "%s", engineName.c_str());

src/overlay_params.cpp

@@ -147,6 +147,8 @@ parse_str(const char *str)
 #define parse_offset_x(s) parse_unsigned(s)
 #define parse_offset_y(s) parse_unsigned(s)
 #define parse_time_format(s) parse_str(s)
+#define parse_io_read(s) parse_unsigned(s)
+#define parse_io_write(s) parse_unsigned(s)
 
 #define parse_crosshair_color(s) parse_color(s)
 

src/overlay_params.h

@@ -73,6 +73,8 @@ extern "C" {
    OVERLAY_PARAM_CUSTOM(crosshair_color)             \
    OVERLAY_PARAM_CUSTOM(background_alpha)            \
    OVERLAY_PARAM_CUSTOM(time_format)                 \
+   OVERLAY_PARAM_CUSTOM(io_read)                     \
+   OVERLAY_PARAM_CUSTOM(io_write)                    \
    OVERLAY_PARAM_CUSTOM(help)
 
 enum overlay_param_position {
@@ -102,6 +104,7 @@ struct overlay_params {
    bool help;
    bool no_display;
    bool full;
+   bool io_read, io_write;
    unsigned width;
    unsigned height;
    unsigned offset_x;

src/string_utils.h

@@ -73,4 +73,15 @@ static bool try_stoi(int& val, const std::string& str, std::size_t* pos = 0, int
     return false;
 }
 
+static bool try_stoull(unsigned long long& val, const std::string& str, std::size_t* pos = 0, int base = 10)
+{
+    try {
+        val = std::stoull(str, pos, base);
+        return true;
+    } catch (std::invalid_argument& e) {
+        std::cerr << __func__ << ": invalid argument: '" << str << "'" << std::endl;
+    }
+    return false;
+}
+
 #pragma GCC diagnostic pop