qt6-bb10/tests
Laszlo Agocs df0e98d408 rhi: Pipeline cache load/save
Add QRhi APIs to retrieve and reload the contents of the "pipeline
cache".

The only API where there is a true pipeline cache is object is Vulkan
(VkPipelineCache). For OpenGL, the other backend where we support this,
it is simulated with program binaries. The Qt 5 style OpenGL program
binary disk cache continues to work like before, but one has now the
option to do things in a more modern, graphics API agnostic way, that
leads to generating a single blob instead of a large set of files in
some system location, allowing easier "pre-baking" of the cache content.

It is expected that Qt Quick exposes the two new functions in form
if QSG_RHI_ environment variables, thus allowing easy testing and
cache file generation.

As an example for the performance improvements this can give, consider
Vulkan, where we do not have any existing persistent caching mechanism
in place:

Running BenchmarkDemoQt6.exe --scene flythrough --mode demo creates 18
QRhiGraphicsPipeline objects from Qt Quick and Qt Quick 3D.

The total time spent in QRhiGraphicsPipeline::create() during application
startup for these 18 pipelines is 35-40 ms on a given Windows (NVIDIA)
system.

When exporting the pipeline cache contents to a file, and then, in a
subsequent run, reloading the cache contents, this is reduced to 5-7 ms
on the same system, meaning we get a 6-7x improvement.

The generated data is always specific to a given Qt version, RHI
backend, graphics device, and driver version. Much of the implementation
consists of adding and verifying the appropriate header to the blobs
retrieved from the driver, to allow gracefully ignoring data that was
generated with a device or driver that differs from the one used at
run time. This should provide robustness, even if the Vulkan or OpenGL
implementation is for some reason not prepared to identity and reject
incompatible cache/program blobs.

Fixes: QTBUG-90398
Change-Id: I67b197f393562434f372c7b7377f638abab85cb3
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
2021-01-22 10:26:03 +01:00
..
auto rhi: Pipeline cache load/save 2021-01-22 10:26:03 +01:00
baselineserver Another round of replacing 0 with nullptr 2020-10-07 23:02:47 +02:00
benchmarks Add simple benchmark for QRegularExpression 2021-01-20 16:31:07 +01:00
global
libfuzzer Fuzzing: Provide link to oss-fuzz 2020-12-11 13:45:25 +00:00
manual rhi: Pipeline cache load/save 2021-01-22 10:26:03 +01:00
shared Replace Q_DECL_UNUSED with [[maybe_unused]] 2020-10-03 11:58:08 +02:00
testserver Network self-test: make it work with docker/containers 2020-11-17 19:56:06 +01:00
CMakeLists.txt CMake: Refactor optimization flag handling and add optimize_full 2020-10-06 10:07:05 +02:00
README
tests.pro Build examples and tests only if their requirements are met 2017-03-22 15:55:55 +00:00

README

This directory contains autotests and benchmarks based on Qt Test. In order
to run the autotests reliably, you need to configure a desktop to match the
test environment that these tests are written for.

Linux X11:

   * The user must be logged in to an active desktop; you can't run the
     autotests without a valid DISPLAY that allows X11 connections.

   * The tests are run against a KDE3 or KDE4 desktop.

   * Window manager uses "click to focus", and not "focus follows mouse". Many
     tests move the mouse cursor around and expect this to not affect focus
     and activation.

   * Disable "click to activate", i.e., when a window is opened, the window
     manager should automatically activate it (give it input focus) and not
     wait for the user to click the window.