Qt6.3 Webengine performance Probleme

MrPaddy

Hallo,

wir haben Qt6.3 via Buildroot inkl. Webengine mit Buildroot gebaut.
Die WebEngine braucht nur sehr lange eine Seite zu rendern bzw. auszuführen. Dadurch wird fast jede Webseite extrem langsam und ruckelig.

Beispielsweise dauert das laden der Youtube Startseite insgesamt etwa 60 bis 80 Sekunden und lässt die CPU lasst (avg bei 4 kernen) auf bis zu 75% steigen.

Beim Laden der Google Startseite geht die CPU auf bis zu 40%. Ein suche zu starten bis 50% und beim einfachen scrollen der Suchergebnisse ebenso.

Im folgendem Screenshots der network performance aus dem RemoteDebugger für das laden der Youtube Startseite. Diese ist hier zwar nach 40s geladen, wird aber erst nach ca. 80 Sekunden vollständig angezeigt. Man kann hier einen Engpass beim „Skripting“ erkennen, welches zusammen um die ~38 sekunden benötigt.

NetworkPerformance_RDebugger2.png.png

Mit selbiger Hardware, aber Qt 5.15.2 für Python (PySide) haben wir diese Probleme nicht.

Das Zielsystem hat entweder ein Congatec IA4 oder Congatec IA5 Board.
Das IA4 Board hat eine Intel Celeron CPU N3160 @ 1.60GHz mit integrierter Gen 8 HD Graphics GPU
Das IA5 Board hat eine Intel Pentium N4200 @ 1.10Ghz mit integrierter Gen 9 HD Graphics GPU

Buildroot:

Architektur: x86_64 (Core i7)
C Library: glibC
Kernel: 4.19.176
QT6 ist für xcb konfiguriert.

Im folgenden die config.summarys:

qt6base


Building for: linux-g++ (x86_64, CPU features: cx16 mmx popcnt sse sse2 sse3 ssse3 sse4.1 sse4.2 sse4)
Compiler: gcc 10.3.0
Build options:
  Mode ................................... debug
  Optimize debug build ................... no
  Fully optimize release builds (-O3) .... no
  Building shared libraries .............. yes
  Using C standard ....................... C11
  Using C++ standard ..................... C++17
  Using ccache ........................... no
  Using new DTAGS ........................ yes
  Generating GDB index ................... no
  Relocatable ............................ yes
  Using precompiled headers .............. no
  Using LTCG ............................. no
  Target compiler supports:
    SSE .................................. SSE2 SSE3 SSSE3 SSE4.1 SSE4.2
    AVX .................................. <none>
    AVX512 ............................... <none>
    Other x86 ............................ AES RDRAND SHA
    Intrinsics without compiler architecture option  yes
  Sanitizers:
    Addresses ............................ no
    Threads .............................. no
    Memory ............................... no
    Fuzzer (instrumentation only) ........ no
    Undefined ............................ no
  Build parts ............................ libs
Qt modules and options:
  Qt Concurrent .......................... yes
  Qt D-Bus ............................... yes
  Qt D-Bus directly linked to libdbus .... yes
  Qt Gui ................................. yes
  Qt Network ............................. yes
  Qt PrintSupport ........................ yes
  Qt Sql ................................. no
  Qt Testlib ............................. yes
  Qt Widgets ............................. yes
  Qt Xml ................................. yes
Support enabled for:
  Using pkg-config ....................... yes
  udev ................................... yes
  Using system zlib ...................... yes
  Zstandard support ...................... no
  Thread support ......................... yes
Common build options:
  Linker can resolve circular dependencies  yes
Qt Core:
  backtrace .............................. yes
  DoubleConversion ....................... yes
    Using system DoubleConversion ........ no
  GLib ................................... yes
  ICU .................................... yes
  Using system libb2 ..................... no
  Built-in copy of the MIME database ..... yes
  Tracing backend ........................ <none>
  Logging backends:
    journald ............................. no
    syslog ............................... no
    slog2 ................................ no
  PCRE2 .................................. yes
    Using system PCRE2 ................... yes
  CLONE_PIDFD support in forkfd .......... yes
Qt Network:
  getifaddrs() ........................... yes
  IPv6 ifname ............................ yes
  libproxy ............................... no
  Linux AF_NETLINK ....................... yes
  OpenSSL ................................ yes
    Qt directly linked to OpenSSL ........ no
  OpenSSL 1.1 ............................ yes
  DTLS ................................... yes
  OCSP-stapling .......................... yes
  SCTP ................................... no
  Use system proxies ..................... yes
  GSSAPI ................................. no
  Brotli Decompression Support ........... no
Qt Gui:
  Accessibility .......................... yes
  FreeType ............................... yes
    Using system FreeType ................ yes
  HarfBuzz ............................... yes
    Using system HarfBuzz ................ yes
  Fontconfig ............................. yes
  Image formats:
    GIF .................................. no
    ICO .................................. yes
    JPEG ................................. yes
      Using system libjpeg ............... yes
    PNG .................................. yes
      Using system libpng ................ yes
  Text formats:
    HtmlParser ........................... yes
    CssParser ............................ yes
    OdfWriter ............................ yes
    MarkdownReader ....................... yes
      Using system libmd4c ............... no
    MarkdownWriter ....................... yes
  EGL .................................... yes
  OpenVG ................................. no
  OpenGL:
    Desktop OpenGL ....................... yes
    OpenGL ES 2.0 ........................ no
    OpenGL ES 3.0 ........................ no
    OpenGL ES 3.1 ........................ no
    OpenGL ES 3.2 ........................ no
  Vulkan ................................. no
  Session Management ..................... yes
Features used by QPA backends:
  evdev .................................. yes
  libinput ............................... yes
  INTEGRITY HID .......................... no
  mtdev .................................. yes
  tslib .................................. no
  xkbcommon .............................. yes
  X11 specific:
    XLib ................................. yes
    XCB Xlib ............................. yes
    EGL on X11 ........................... yes
    xkbcommon-x11 ........................ yes
    xcb-sm ............................... yes
QPA backends:
  DirectFB ............................... no
  EGLFS .................................. yes
  EGLFS details:
    EGLFS OpenWFD ........................ no
    EGLFS i.Mx6 .......................... no
    EGLFS i.Mx6 Wayland .................. no
    EGLFS RCAR ........................... no
    EGLFS EGLDevice ...................... yes
    EGLFS GBM ............................ yes
    EGLFS VSP2 ........................... no
    EGLFS Mali ........................... no
    EGLFS Raspberry Pi ................... no
    EGLFS X11 ............................ yes
  LinuxFB ................................ no
  VNC .................................... yes
  VK_KHR_display ......................... no
  QNX:
    lgmon ................................ no
    IMF .................................. no
  XCB:
    Using system-provided xcb-xinput ..... yes
    GL integrations:
      GLX Plugin ......................... yes
        XCB GLX .......................... yes
      EGL-X11 Plugin ..................... yes
  Windows:
    Direct 2D ............................ no
    Direct 2D 1.1 ........................ no
    DirectWrite .......................... no
    DirectWrite 3 ........................ no
Qt Widgets:
  GTK+ ................................... no
  Styles ................................. Fusion Windows
Qt Testlib:
  Tester for item models ................. yes
Qt PrintSupport:
  CUPS ................................... no
Note: Disabling X11 Accessibility Bridge: D-Bus or AT-SPI is missing.

qt6webengine:

WebEngine Repository Build Options:
  Build Ninja ............................ no
  Build Gn ............................... no
  Jumbo Build ............................ yes
  Developer build ........................ no
  Build QtWebEngine Modules:
    Build QtWebEngineCore ................ yes
    Build QtWebEngineWidgets ............. yes
    Build QtWebEngineQuick ............... yes
  Build QtPdf Modules:
    Build QtPdfWidgets ................... no
    Build QtPdfQuick ..................... no
  Optional system libraries:
    re2 .................................. no
    icu .................................. no
    libwebp, libwebpmux and libwebpdemux . yes
    opus ................................. yes
    ffmpeg ............................... yes
    libvpx ............................... yes
    snappy ............................... no
    glib ................................. yes
    zlib ................................. yes
    minizip .............................. no
    libevent ............................. no
    libxml2 and libxslt .................. no
    lcms2 ................................ no
    png .................................. yes
    jpeg ................................. yes
    harfbuzz ............................. yes
    freetype ............................. yes
    libpci ............................... no
Qt WebEngineCore:
  Embedded build ......................... yes
  Full debug information ................. no
  Sanitizer support ...................... no
  Pepper Plugins ......................... no
  Printing and PDF ....................... no
  Proprietary Codecs ..................... no
  Spellchecker ........................... no
  Native Spellchecker .................... no
  WebRTC ................................. no
  PipeWire over GIO ...................... no
  Geolocation ............................ yes
  WebChannel support ..................... yes
  Kerberos Authentication ................ no
  Extensions ............................. no
  Support GLX on qpa-xcb ................. yes
  Use ALSA ............................... yes
  Use PulseAudio ......................... no
Qt WebEngineQuick:
  UI Delegates ........................... yes

qt6declarative


Qt QML:
  QML network support .................... yes
  QML debugging and profiling support .... yes
  QML just-in-time compiler .............. yes
  QML sequence object .................... yes
  QML XML http request ................... yes
  QML Locale ............................. yes
Qt QML Models:
  QML list model ......................... yes
  QML delegate model ..................... yes
Qt Quick:
  AnimatedImage item ..................... yes
  Canvas item ............................ yes
  Support for Qt Quick Designer .......... yes
  Flipable item .......................... yes
  GridView item .......................... yes
  ListView item .......................... yes
  TableView item ......................... yes
  Path support ........................... yes
  PathView item .......................... yes
  Positioner items ....................... yes
  Repeater item .......................... yes
  ShaderEffect item ...................... yes
  Sprite item ............................ yes
Qt Quick Templates 2:
  Hover support .......................... yes
  Multi-touch support .................... yes
Qt Quick Controls 2:
  Styles ................................. Basic Fusion Imagine Material Universal macOS Windows

qt6multimedia:

Qt Multimedia:
  GStreamer 1.0 .......................... yes
  Video for Linux ........................ yes
  Linux DMA buffer support ............... yes
  MMRenderer ............................. no
  AVFoundation ........................... no
  Windows Media Foundation ............... no

qt6tools

Qt Tools:
  Qt Assistant ........................... no
  QDoc ................................... no
  Clang-based lupdate parser ............. no
  Qt Designer ............................ yes
  Qt Distance Field Generator ............ no
  Qt Linguist ............................ yes
  Mac Deployment Tool .................... no
  pixeltool .............................. no
  qdbus .................................. no
  Qt Attributions Scanner ................ no
  qtdiag ................................. no
  qtplugininfo ........................... no
  Windows deployment tool ................ no
WARNING: QDoc will not be compiled, probably because libclang could not be located. This means that you cannot build the Qt documentation.
Either set CMAKE_PREFIX_PATH or LLVM_INSTALL_DIR to the location of your llvm installation.
On Linux systems, you may be able to install libclang by installing the libclang-dev or libclang-devel package, depending on your distribution.
On macOS, you can use Homebrew's llvm package.
You will also need to set the FEATURE_clang CMake variable to ON to re-evaluate this check.
WARNING: Clang-based lupdate parser will not be available. LLVM and Clang C++ libraries have not been found.
You will need to set the FEATURE_clangcpp CMake variable to ON to re-evaluate this check.

qtremoteobjects

Qt Remote Objects:
  High Availability Manager (ham) ........ no

Der Webbrowser an sich ist der QuickNanoBrowser aus den QT-Beispielen.

Ich habe folgende Startargumente für den Webbrowser ausprobiert:

--ignore-gpu-blocklist
--enable-gpu-rasterization
--enable-features=VaapiVideoDecoder
--disable-features=UseChromeOSDirectVideoDecoder

Dadurch laden die Grafiken etwas schneller. Das große performance Problem löst dies allerdings nicht.

Beim laden verschiedener Webseiten kam fast immer auch folgende Warnung daher:

8360:8396:0512/142144.932823:WARNING:http_cache_transaction.cc(1192)] Unable to open or create cache entry

Als ich dann den Grafiktreiber vom Mesa DRI 915 auf Gallium 915 geändert habe sind diese Warnungen verschwunden. Leider fehlt mir hier das Hintergrundwissen um zu sagen, dass dieses Problem damit gelöst ist.

Im folgendem die Konsolenausgabe beim Start des Browsers. Direkt in der ersten Meldung fällt auf, dass das Sandboxing offenbar nicht funktioniert.

lang:  "en"
[4711:4711:0523/165343.765238:INFO:zygote_host_impl_linux.cc(117)] No usable sandbox! Update your kernel or see https://chromium.googlesource.com/chromium/src/+/master/docs/linux/suid_sandbox_development.md for more information on developing with the SUID sandbox. If you want to live dangerously and need an immediate workaround, you can try using --no-sandbox.
qt.webenginecontext:

GLImplementation: desktop
Surface Type: OpenGL
Surface Profile: NoProfile
Surface Version: 3.0
Using Default SG Backend: yes
Using Software Dynamic GL: no
Using Angle: no

Init Parameters:
  *  application-name Web
  *  browser-subprocess-path /usr/libexec/QtWebEngineProcess
  *  disable-features DnsOverHttpsUpgrade,ConsolidatedMovementXY,InstalledApp,BackgroundFetch,WebOTP,WebPayments,WebUSB,PictureInPicture
  *  disable-setuid-sandbox
  *  disable-speech-api
  *  enable-features NetworkServiceInProcess,TracingServiceInProcess
  *  enable-threaded-compositing
  *  gpu-preferences UAAAAAAAAAAoAAAQAAAAAAAAAAAAAAAAAABgAAAAAAAwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAgAAAAAAAAACAAAAAAAAAAAAAAAAAAAAAIAAAAAAAAAAgAAAAAAAAACAAAAAAAAAA=
  *  in-process-gpu
  *  use-gl desktop

Testweise habe ich das –no-sandbox Flag ausprobiert. Damit ist die "no usable sandbox" - Meldung dann zwar weg, aber das performance Problem besteht weiterhin. Sandboxing soll letztendlich aber aktiviert sein.
Kann das fehlende Sandboxing denn ggf. mit der schlechten Performance zusammenhängen?

Im folgenden Screenshots von chrome://gpu (ohne Startargumente):

Leider habe ich keine passenden Lösungen in diesem Forum gefunden. Kann hier jemand weiterhelfen?