Introduce per process GPU usage metrics

.github/workflows/test.yml

@@ -41,4 +41,5 @@ jobs:
           export XDG_RUNTIME_DIR="$(mktemp --tmpdir -d xdg-runtime-XXXXXX)"
           weston --backend=headless --socket=wayland-1 --idle-time=0 &
           dbus-run-session -- env WAYLAND_DISPLAY=wayland-1 meson test -C build --suite monitor-gui-headless "*:" --print-errorlogs
-          # non-headless gui example: meson test -C build --suite monitor "*:" --print-errorlogs
+          # This test has been disabled, because it wasn't running correctly on CI
+          # dbus-run-session -- env WAYLAND_DISPLAY=wayland-1 meson test -C build --suite monitor-backend "*:" --print-errorlogs

meson.build

@@ -62,9 +62,10 @@ app_dependencies = [
 
 config_data = configuration_data()
 config_data.set('GETTEXT_PACKAGE', meson.project_name())
-
 subdir('data')
 
+config_data.set('TESTASSETSDIR', meson.project_build_root () / 'tests/assets/')
+
 config_data.set('VCS_TAG', '@VCS_TAG@')
 project_config = vcs_tag(
     input: configure_file(

src/Conf.vala.in

@@ -1,5 +1,6 @@
 namespace Monitor {
     public const string DBDIR = "@DBDIR@";
     public const string GETTEXT_PACKAGE = "@GETTEXT_PACKAGE@";
+    public const string TESTASSETSDIR = "@TESTASSETSDIR@";
     public const string VCS_TAG = "@VCS_TAG@";
 }

src/Managers/Process.vala

@@ -42,6 +42,9 @@ public class Monitor.Process : GLib.Object {
     // Contains info about io
     public ProcessIO io;
 
+    // Contains info about GPU usage
+    private ProcessDRM drm;
+
     // Contains status info
     public ProcessStatus stat;
 
@@ -61,26 +64,29 @@ public class Monitor.Process : GLib.Object {
     private uint64 cpu_last_used;
 
     // Memory usage of the process, measured in KiB.
-
     public uint64 mem_usage { get; private set; }
     public double mem_percentage { get; private set; }
 
-    private uint64 last_total;
+    public double gpu_percentage { get; private set; }
+
+    private uint64 last_total; // @TODO: Obsolete?
 
     const int HISTORY_BUFFER_SIZE = 30;
-    public Gee.ArrayList<double ? > cpu_percentage_history = new Gee.ArrayList<double ? > ();
-    public Gee.ArrayList<double ? > mem_percentage_history = new Gee.ArrayList<double ? > ();
+    public Gee.ArrayList<double ?> cpu_percentage_history = new Gee.ArrayList<double?> ();
+    public Gee.ArrayList<double ?> mem_percentage_history = new Gee.ArrayList<double?> ();
 
 
 
     // Construct a new process
-    public Process (int _pid) {
+    public Process (int _pid, int update_interval) {
         _icon = ProcessUtils.get_default_icon ();
 
         open_files_paths = new Gee.HashSet<string> ();
 
         last_total = 0;
 
+        drm = new ProcessDRM (_pid, update_interval);
+
         io = {};
         stat = {};
         stat.pid = _pid;
@@ -101,15 +107,18 @@ public class Monitor.Process : GLib.Object {
         exists = parse_stat () && read_cmdline ();
         get_children_pids ();
         get_usage (0, 1);
-    }
 
+        gpu_percentage = 0;
+    }
 
     // Updates the process to get latest information
     // Returns if the update was successful
     public bool update (uint64 cpu_total, uint64 cpu_last_total) {
         exists = parse_stat ();
         if (exists) {
             get_usage (cpu_total, cpu_last_total);
+            drm.update ();
+            gpu_percentage = drm.gpu_percentage;
             parse_io ();
             parse_statm ();
             get_open_files ();
@@ -280,8 +289,8 @@ public class Monitor.Process : GLib.Object {
     }
 
     /**
-     * Reads the /proc/%pid%/cmdline file and updates from the information contained therein.
-     */
+    * Reads the /proc/%pid%/cmdline file and updates from the information contained therein.
+    */
     private bool read_cmdline () {
         string ? cmdline = ProcessUtils.read_file ("/proc/%d/cmdline".printf (stat.pid));
 
@@ -301,6 +310,7 @@ public class Monitor.Process : GLib.Object {
         return true;
     }
 
+    // @TODO: Divide into get_usage_cpu and get_usage_mem and write some tests
     private void get_usage (uint64 cpu_total, uint64 cpu_last_total) {
         // Get CPU usage by process
         GTop.ProcTime proc_time;

src/Managers/ProcessDRM.vala

@@ -0,0 +1,192 @@
+/*
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ * SPDX-FileCopyrightText: 2026 elementary, Inc. (https://elementary.io)
+ */
+
+public class Monitor.ProcessDRM : GLib.Object {
+
+    private string driver;
+
+    /**
+     * Time spent busy in nanoseconds by the render engine executing
+     * workloads from the last time it was read
+     */
+    private uint64 last_engine_render = 0;
+    private uint64 last_engine_gfx = 0;
+
+    private uint64 engine_gfx;
+    private uint64 engine_render;
+
+    // Xe driver related fields
+    private uint64 cycles_rcs = 0;
+    private uint64 cycles_rcs_total = 0;
+
+    private uint64 cycles_ccs = 0;
+    private uint64 cycles_ccs_total = 0;
+
+    private uint64 delta_rcs = 0;
+    private uint64 delta_total_rcs = 0;
+
+    private uint64 delta_ccs = 0;
+    private uint64 delta_total_ccs = 0;
+
+    public double gpu_percentage { get; private set; }
+
+    private int pid;
+    private int update_interval;
+    private Gee.ArrayList<GLib.File> drm_files;
+
+    internal string path_fdinfo;
+    internal string path_fd;
+
+    public ProcessDRM (int pid, int update_interval) {
+        this.pid = pid;
+        this.update_interval = update_interval;
+
+        path_fdinfo = "/proc/%d/fdinfo".printf (pid);
+        path_fd = "/proc/%d/fd".printf (pid);
+
+        get_drm_files ();
+    }
+
+    public ProcessDRM.with_paths (int pid, int update_interval, string path_fdinfo, string path_fd) {
+        this.pid = pid;
+        this.update_interval = update_interval;
+        this.path_fdinfo = path_fdinfo;
+        this.path_fd = path_fd;
+
+        get_drm_files ();
+    }
+
+    private void get_drm_files () {
+    drm_files = new Gee.ArrayList<GLib.File ?> ();
+
+        try {
+            Dir dir = Dir.open (path_fdinfo, 0);
+            string ? name = null;
+
+            while ((name = dir.read_name ()) != null) {
+
+                // skip standard fds
+                if (name == "0" || name == "1" || name == "2") {
+                    continue;
+                }
+                string path = Path.build_filename (path_fdinfo, name);
+
+                int fd_dir_fd = Posix.open (path_fd, Posix.O_RDONLY | Posix.O_DIRECTORY);
+                if (fd_dir_fd == -1) {
+                    warning ("Cannot open file descriptor: %s", path_fd);
+                    continue;
+                }
+
+                bool is_drm = ProcessUtils.is_drm_fd (fd_dir_fd, name);
+                Posix.close (fd_dir_fd);
+
+                if (is_drm) {
+                    var drm_file = File.new_for_path (path);
+                    drm_files.add (drm_file);
+                    debug ("Found DRM file: %s", path);
+                }
+            }
+        } catch (FileError err) {
+            // prevent flooding logs with permission errors
+            if (!(err is FileError.ACCES)) {
+                warning (err.message);
+            }
+        }
+        // debug ("Found %d drm fdinfo files for pid %d", drm_files.size, pid);
+    }
+
+    public void update () {
+        if (drm_files.size == 0) {
+            gpu_percentage = 0;
+            return;
+        }
+
+        foreach (var drm_file in drm_files) {
+            try {
+                var dis = new DataInputStream (drm_file.read ());
+                string ? line;
+                while ((line = dis.read_line ()) != null) {
+                    parse_drm_line (line);
+                }
+            } catch (Error err) {
+                if (!(err is FileError.ACCES)) {
+                    warning ("Can't read fdinfo: '%s' %d", err.message, err.code);
+                }
+            }
+            break;
+        }
+
+        // Every GPU driver creates a bit different DRM file content,
+        // so we need to use a specific gpu percentage calculation functions
+        switch (driver) {
+        case "i915":
+            calculate_percentage_ns (ref engine_render, ref last_engine_render);
+            break;
+        case "xe":
+            calculate_percentage_cycles (ref delta_rcs, ref delta_total_rcs);
+            break;
+        case "amdgpu":
+             calculate_percentage_ns (ref engine_gfx, ref last_engine_gfx);
+             break;
+        default:
+            // Handle default case
+            gpu_percentage = -1;
+            break;
+        }
+    }
+
+    private void calculate_percentage_ns (ref uint64 engine, ref uint64 last_engine) {
+        if (last_engine != 0) {
+            // Since values in the files are in nanoseconds, it is also needed to convert
+            // the interval to nanoseconds (10^9)
+            gpu_percentage = 100 * ((double) (engine - last_engine)) / (update_interval * 1e9);
+        }
+        last_engine = engine;
+    }
+
+    private void calculate_percentage_cycles (ref uint64 delta, ref uint64 delta_total) {
+        var fraction = (float) delta / (float) delta_total;
+        gpu_percentage = delta_total > 0 ? 100 * (fraction.clamp (0.0f, 1.0f)) : 0;
+    }
+
+    private void update_cycles (string line, ref uint64 last_cycles, ref uint64 delta) {
+        var cycles = uint64.parse (line.strip ().split (" ")[0]);
+        delta = cycles > last_cycles ? cycles - last_cycles : 0;
+        last_cycles = cycles;
+    }
+
+    private void parse_drm_line (string line) {
+        var splitted_line = line.split (":");
+        switch (splitted_line[0]) {
+        case "drm-driver":
+            driver = splitted_line[1].strip ();
+            break;
+        case "drm-engine-gfx":
+            engine_gfx = uint64.parse (splitted_line[1].strip ().split (" ")[0]);
+            break;
+        // for i915 there is only drm-engine-render to check
+        case "drm-engine-render":
+            engine_render = uint64.parse (splitted_line[1].strip ().split (" ")[0]);
+            break;
+        // Xe driver specific entries
+        case "drm-cycles-ccs":
+            update_cycles (splitted_line[1], ref cycles_ccs, ref delta_ccs);
+            break;
+        case "drm-total-cycles-ccs":
+            update_cycles (splitted_line[1], ref cycles_ccs_total, ref delta_total_ccs);
+            break;
+        case "drm-cycles-rcs":
+            update_cycles (splitted_line[1], ref cycles_rcs, ref delta_rcs);
+            break;
+        case "drm-total-cycles-rcs":
+            update_cycles (splitted_line[1], ref cycles_rcs_total, ref delta_total_rcs);
+            break;
+        default:
+            // Ignore other entries
+            break;
+        }
+    }
+
+}

src/Managers/ProcessManager.vala

@@ -259,7 +259,8 @@ namespace Monitor {
          */
         private Process ? add_process (int pid, bool lazy_signal = false) {
             // create the process
-            var process = new Process (pid);
+            int update_interval = MonitorApp.settings.get_int ("update-time");
+            var process = new Process (pid, update_interval);
 
             if (!process.exists) {
                 return null;

src/Managers/ProcessUtils.vala

@@ -67,4 +67,12 @@ public class Monitor.ProcessUtils {
             return null;
         }
     }
+
+    // Based on nvtop
+    // https://github.com/Syllo/nvtop/blob/4bf5db248d7aa7528f3a1ab7c94f504dff6834e4/src/extract_processinfo_fdinfo.c#L88
+    public static bool is_drm_fd (int fd_dir_fd, string name) {
+        Posix.Stat stat;
+        int ret = Posix.fstatat (fd_dir_fd, name, out stat, 0);
+        return ret == 0 && (stat.st_mode & Posix.S_IFMT) == Posix.S_IFCHR && Posix.major (stat.st_rdev) == 226;
+    }
 }

src/Models/ProcessRowData.vala

@@ -3,12 +3,15 @@
  * SPDX-FileCopyrightText: 2026 elementary, Inc. (https://elementary.io)
  */
 
-/* This class holds data from Process class to use in the ColumnView */
+/**
+ * This class holds data from Process class to use in the ColumnView
+ */
 public class Monitor.ProcessRowData : GLib.Object {
     public Icon icon { get; set; }
     public string name { get; set; }
     public int cpu { get; set; }
     public uint64 memory { get; set; }
+    public int gpu { get; set; }
     public int pid { get; set; }
     public string cmd { get; set; }
     public Gee.HashMap<string, Binding> bindings = new Gee.HashMap<string, Binding> ();

src/Models/TreeViewModel.vala

@@ -83,6 +83,7 @@ public class Monitor.TreeViewModel : GLib.Object {
                 name = process.application_name,
                 cpu = (int) process.cpu_percentage,
                 memory = process.mem_usage,
+                gpu = (int) process.gpu_percentage,
                 pid = process.stat.pid,
                 cmd = process.command
             };
@@ -112,6 +113,7 @@ public class Monitor.TreeViewModel : GLib.Object {
             var item = (ProcessRowData) store.get_item (pos);
             item.cpu = (int) process.cpu_percentage;
             item.memory = process.mem_usage;
+            item.gpu = (int) process.gpu_percentage;
             sorter.changed (DIFFERENT);
         }
     }

src/Resources/Resources.vala

@@ -4,6 +4,12 @@
  */
 
 public class Monitor.Resources : Object {
+
+    private static GLib.Once<Resources> instance;
+    public static unowned Resources get_default () {
+        return instance.once (() => { return new Resources (); });
+    }
+
     public CPU cpu;
     public Memory memory;
     public Swap swap;