fix(linux/glad): add EGL_IMG_context_priority & EGL_NV_context_priority_realtime

Resolves encoding throttling:
* Try to create EGL context with realtime or high priority if supported.
* Set CAP_SYS_NICE capability (needed for AMDGPU priority queues above NORMAL).

Currently has no effect on AMDGPU with Flatpak, AppImage and/or with
Portal capture. Other GPUs may behave differently.

Author: psyke83

cmake/dependencies/glad.cmake

@@ -179,10 +179,12 @@ glad_add_library(glad_egl
             EGL_EXT_platform_base
             EGL_EXT_platform_wayland
             EGL_EXT_platform_x11
+            EGL_IMG_context_priority
             EGL_KHR_create_context
             EGL_KHR_image_base
             EGL_KHR_surfaceless_context
             EGL_MESA_platform_gbm
+            EGL_NV_context_priority_realtime
 )
 
 # GL compatibility=4.6 --loader --mx

cmake/packaging/linux.cmake

@@ -64,7 +64,7 @@ endif()
 
 # Apply setcap for RPM
 # https://github.com/coreos/rpm-ostree/discussions/5036#discussioncomment-10291071
-set(CPACK_RPM_USER_FILELIST "%caps(cap_sys_admin+p) ${SUNSHINE_EXECUTABLE_PATH}")
+set(CPACK_RPM_USER_FILELIST "%caps(cap_sys_admin,cap_sys_nice+p) ${SUNSHINE_EXECUTABLE_PATH}")
 
 # Dependencies
 set(CPACK_DEB_COMPONENT_INSTALL ON)

docs/building.md

@@ -59,7 +59,7 @@ from source and using the binary directly, this will also work:
 
 ```bash
 sudo cp build/sunshine /tmp
-sudo setcap cap_sys_admin+p /tmp/sunshine
+sudo setcap cap_sys_admin,cap_sys_nice+p /tmp/sunshine
 sudo getcap /tmp/sunshine
 sudo mv /tmp/sunshine build/sunshine
 ```

packaging/linux/AppImage/AppRun

@@ -60,7 +60,7 @@ function install() {
   sed -i -e "s#$SUNSHINE_PATH#$(readlink -f $ARGV0)#g" ~/.config/systemd/user/app-dev.lizardbyte.app.Sunshine.service
 
   # setcap
-  sudo setcap cap_sys_admin+p "$(readlink -f "$SUNSHINE_BIN_HERE")"
+  sudo setcap cap_sys_admin,cap_sys_nice+p "$(readlink -f "$SUNSHINE_BIN_HERE")"
 }
 
 function remove() {

packaging/linux/Arch/sunshine.install

@@ -1,5 +1,5 @@
 do_setcap() {
-  setcap cap_sys_admin+p $(readlink -f usr/bin/sunshine)
+  setcap cap_sys_admin,cap_sys_nice+p $(readlink -f usr/bin/sunshine)
 }
 
 do_udev_reload() {

packaging/linux/copr/Sunshine.spec

@@ -387,8 +387,8 @@ fi
 
 %files
 # Executables
-%caps(cap_sys_admin+p) %{_bindir}/sunshine
-%caps(cap_sys_admin+p) %{_bindir}/sunshine-*
+%caps(cap_sys_admin,cap_sys_nice+p) %{_bindir}/sunshine
+%caps(cap_sys_admin,cap_sys_nice+p) %{_bindir}/sunshine-*
 
 # Systemd unit files for user services
 %{_userunitdir}/*.service

src/platform/linux/graphics.cpp

@@ -11,6 +11,11 @@
 #include "src/logging.h"
 #include "src/video.h"
 
+// platform includes
+#if !defined(__FreeBSD__)
+  #include <sys/capability.h>
+#endif
+
 extern "C" {
 #include <libavutil/pixdesc.h>
 }
@@ -387,6 +392,18 @@ namespace egl {
   }
 
   std::optional<ctx_t> make_ctx(display_t::pointer display) {
+    bool nice_warning = false;
+#if !defined(__FreeBSD__)
+    cap_t caps = cap_get_proc();
+
+    cap_value_t sys_nice = CAP_SYS_NICE;
+    if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &sys_nice, CAP_SET) || cap_set_proc(caps)) {
+      BOOST_LOG(debug) << "Failed to gain CAP_SYS_NICE"sv;
+      nice_warning = true;
+    }
+    cap_free(caps);
+#endif
+
     constexpr int conf_attr[] {
       EGL_RENDERABLE_TYPE,
       EGL_OPENGL_BIT,
@@ -405,20 +422,48 @@ namespace egl {
       return std::nullopt;
     }
 
-    constexpr int attr[] {
-      EGL_CONTEXT_CLIENT_VERSION,
-      3,
-      EGL_NONE
-    };
+    const char *extension_st = eglQueryString(display, EGL_EXTENSIONS);
+
+    std::vector<EGLint> attr;
+    attr.push_back(EGL_CONTEXT_CLIENT_VERSION);
+    attr.push_back(3);
+
+    // Only add the realtime/high priority attribute if the driver explicitly supports it
+    if (extension_st && std::string_view(extension_st).contains("EGL_NV_context_priority_realtime"sv)) {
+      BOOST_LOG(debug) << "EGL: Realtime priority context supported"sv;
+      attr.push_back(EGL_CONTEXT_PRIORITY_LEVEL_IMG);
+      attr.push_back(EGL_CONTEXT_PRIORITY_REALTIME_NV);
+    } else if (extension_st && std::string_view(extension_st).contains("EGL_IMG_context_priority"sv)) {
+      BOOST_LOG(debug) << "EGL: High priority context supported"sv;
+      attr.push_back(EGL_CONTEXT_PRIORITY_LEVEL_IMG);
+      attr.push_back(EGL_CONTEXT_PRIORITY_HIGH_IMG);
+    }
+    attr.push_back(EGL_NONE);
 
-    ctx_t ctx {display, eglCreateContext(display, conf, EGL_NO_CONTEXT, attr)};
-    if (fail()) {
+    EGLContext raw_ctx = eglCreateContext(display, conf, EGL_NO_CONTEXT, attr.data());
+    if (raw_ctx == EGL_NO_CONTEXT) {
       BOOST_LOG(error) << "Couldn't create EGL context: ["sv << util::hex(eglGetError()).to_string_view() << ']';
       return std::nullopt;
     }
 
-    TUPLE_EL_REF(ctx_p, 1, ctx.el);
-    if (!eglMakeCurrent(display, EGL_NO_SURFACE, EGL_NO_SURFACE, ctx_p)) {
+    ctx_t ctx {display, raw_ctx};
+
+    EGLint actual_priority = EGL_CONTEXT_PRIORITY_MEDIUM_IMG;
+    std::string actual_priority_str = "MEDIUM";
+    if (eglQueryContext(display, raw_ctx, EGL_CONTEXT_PRIORITY_LEVEL_IMG, &actual_priority)) {
+      if (actual_priority == EGL_CONTEXT_PRIORITY_REALTIME_NV) {
+        actual_priority_str = "REALTIME";
+      } else if (actual_priority == EGL_CONTEXT_PRIORITY_HIGH_IMG) {
+        actual_priority_str = "HIGH";
+      }
+      if (nice_warning) {
+        BOOST_LOG(warning) << "EGL: Context Priority set to "sv << actual_priority_str << " but CAP_SYS_NICE capability is missing"sv;
+      } else {
+        BOOST_LOG(info) << "EGL: Context Priority set to "sv << actual_priority_str;
+      }
+    }
+
+    if (!eglMakeCurrent(display, EGL_NO_SURFACE, EGL_NO_SURFACE, raw_ctx)) {
       BOOST_LOG(error) << "Couldn't make current display"sv;
       return std::nullopt;
     }
@@ -453,6 +498,14 @@ namespace egl {
 
     gl::ctx.PixelStorei(GL_UNPACK_ALIGNMENT, 1);
 
+#if !defined(__FreeBSD__)
+    caps = cap_get_proc();
+    if (cap_set_flag(caps, CAP_EFFECTIVE, 1, &sys_nice, CAP_CLEAR) || cap_set_proc(caps)) {
+      BOOST_LOG(debug) << "Failed to drop CAP_SYS_NICE"sv;
+    }
+    cap_free(caps);
+#endif
+
     return ctx;
   }
 

src/platform/linux/portalgrab.cpp

@@ -231,18 +231,19 @@ namespace portal {
 
     void finalize_portal_security() {
 #if !defined(__FreeBSD__)
-      BOOST_LOG(debug) << "Finalizing Portal security: dropping CAP_SYS_ADMIN and resetting dumpable"sv;
+      BOOST_LOG(debug) << "Finalizing Portal security: dropping capabilities and resetting dumpable"sv;
 
       cap_t caps = cap_get_proc();
       if (!caps) {
         BOOST_LOG(error) << "Failed to get process capabilities"sv;
         return;
       }
 
-      std::array<cap_value_t, 1> remove_list {CAP_SYS_ADMIN};
+      std::array<cap_value_t, 2> effective_list {CAP_SYS_ADMIN, CAP_SYS_NICE};
+      std::array<cap_value_t, 2> permitted_list {CAP_SYS_ADMIN, CAP_SYS_NICE};
 
-      cap_set_flag(caps, CAP_PERMITTED, remove_list.size(), remove_list.data(), CAP_CLEAR);
-      cap_set_flag(caps, CAP_EFFECTIVE, remove_list.size(), remove_list.data(), CAP_CLEAR);
+      cap_set_flag(caps, CAP_EFFECTIVE, effective_list.size(), effective_list.data(), CAP_CLEAR);
+      cap_set_flag(caps, CAP_PERMITTED, permitted_list.size(), permitted_list.data(), CAP_CLEAR);
 
       if (cap_set_proc(caps) != 0) {
         BOOST_LOG(error) << "Failed to prune capabilities: "sv << std::strerror(errno);

src_assets/linux/misc/postinst

@@ -12,10 +12,10 @@ if [ ! -x "$(command -v rpm-ostree)" ]; then
   path_to_setcap=$(which setcap)
   path_to_sunshine=$(readlink -f "$(which sunshine)")
   if [ -x "$path_to_setcap" ] ; then
-    echo "Setting CAP_SYS_ADMIN capability on Sunshine binary."
-    echo "$path_to_setcap cap_sys_admin+p $path_to_sunshine"
-    $path_to_setcap cap_sys_admin+p $path_to_sunshine
-    echo "CAP_SYS_ADMIN capability set on Sunshine binary."
+    echo "Setting CAP_SYS_ADMIN, CAP_SYS_NICE capabilities on Sunshine binary."
+    echo "$path_to_setcap cap_sys_admin,cap_sys_nice+p $path_to_sunshine"
+    $path_to_setcap cap_sys_admin,cap_sys_nice+p $path_to_sunshine
+    echo "CAP_SYS_ADMIN, CAP_SYS_NICE capabilities set on Sunshine binary."
   else
     echo "error: setcap not found or not executable."
   fi