Karim Pinter
da7ca1ee75
The switch of the VxWorks guests' NFS mounts from TCP to UDP removed
transport-level backpressure and retransmission: when the server drops
a request or a reply, the client re-sends the RPC itself. With
VXWORKS_QEMU_INSTANCES=4 KVM-speed x86 guests hammering the server
concurrently, drops are frequent enough that non-idempotent metadata
ops (MKDIR, RENAME, REMOVE) get replayed, which surfaces as spurious
errors and crashed autotests in exactly the metadata-heavy paths
(QSettings, QFileDialog, tst_QFile::openDirectory).
Address the three drop points on the server:
- nfsd threads: the distro default of 8 is too few; when all of them
block in a commit, incoming UDP requests are silently discarded.
Raise to 32.
- sync exports: commit latency under parallel load exceeds the
client's RPC timeout and triggers the retransmit storms above.
Export async instead; the exports carry disposable CI scratch data,
so relaxed durability is acceptable.
- socket buffers and fragment reassembly: NFS3 rsize/wsize over a
1500-byte MTU turns every large reply (READ, READDIRPLUS) into an
IP fragment train, and one lost fragment costs the whole RPC. Raise
rmem/wmem to 8 MiB and the ipfrag thresholds to 16/12 MiB, applied
on every boot since sysctls do not persist.
Also use exportfs -ra so changed export options are resynced on VMs
that already carry the exports from a previous run.
TMP,HOME,CACHE directories were in NFS, now they are moved to ramfs
on the device side. imx6 ram increased to 4G because of this.
This also includes the NFS patch from WindRiver.
Fixes: QTBUG-149201
Change-Id: I710d81789d6cdd7b4de40bba0c55086ea61724fd
Reviewed-by: Toni Saario <toni.saario@qt.io>
(cherry picked from commit 58b1334bac)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
HOW TO BUILD Qt 6
Synopsis
System requirements
- C++ compiler supporting the C++17 standard
- CMake
- Ninja
- Python 3
For more details, see also https://doc.qt.io/qt-6/build-sources.html
Linux, Mac:
cd <path>/<source_package>
./configure -prefix $PWD/qtbase
cmake --build .
Windows:
- Open a command prompt.
- Ensure that the following tools can be found in the path:
- Supported compiler (Visual Studio 2022 or later, or MinGW-builds gcc 13.1 or later)
- Python 3 ([https://www.python.org/downloads/windows/] or from Microsoft Store)
cd <path>\<source_package>
configure -prefix %CD%\qtbase
cmake --build .
More details follow.
Build!
Qt is built with CMake, and a typical
configure && cmake --build . build process is used.
If Ninja is installed, it is automatically chosen as CMake generator.
Some relevant configure options (see configure -help):
-releaseCompile and link Qt with debugging turned off.-debugCompile and link Qt with debugging turned on.
Example for a release build:
./configure -prefix $PWD/qtbase
cmake --build .
Example for a developer build: (enables more autotests, builds debug version of libraries, ...)
./configure -developer-build
cmake --build .
See output of ./configure -help for documentation on various options to
configure.
The above examples will build whatever Qt modules have been enabled by default in the build system.
It is possible to build selected repositories with their dependencies by doing
a ninja <repo-name>/all. For example, to build only qtdeclarative,
and the modules it depends on:
./configure
ninja qtdeclarative/all
This can save a lot of time if you are only interested in a subset of Qt.
Hints
The submodule repository qtrepotools contains useful scripts for
developers and release engineers. Consider adding qtrepotools/bin
to your PATH environment variable to access them.
Building Qt from git
See http://wiki.qt.io/Building_Qt_6_from_Git and README.git for more information. See http://wiki.qt.io/Qt_6 for the reference platforms.
Documentation
After configuring and compiling Qt, building the documentation is possible by running
cmake --build . --target docs
After having built the documentation, you need to install it with the following command:
cmake --build . --target install_docs
The documentation is installed in the path specified with the
configure argument -docdir.
Information about Qt's documentation is located in qtbase/doc/README
Note: Building the documentation is only tested on desktop platforms.