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[KevinH]

Okay, I tested those patches and they both apply cleanly inside the qtwebengine directory as follows:

cd qtwebengine

patch -R -p1 < ddcd304.diff # reversing that patch

patch -p1 < 9dd5105.diff

I am rebuilding with those patches in place on my older machine so it may be an hour or so just to rebuild qtwebengine.

I will let you know if I run into any issues.

Update:

It was a fast rebuild. And the build completed with no issues with those patches in place.

[DiapDealer]

I suppose the Python script I use to download/patch sources and kick off the compilation of the individual modules could factor into the slow-down, but I don't see how. It was always painfully slow even before I scripted things.

[KevinH]

Could be, if you use the Qt single package the build runs in parallel across all qt modules.
They have really done a good job speeding the builds up using cmake at least they did on macos and Linux. Full Qt 5.15 builds on my old macOS box took about 8 hours. Recent Qt6 builds (and the codesize has really increased since Qt5) now take 3 hours on that same machine.

[DiapDealer]

I just can't manage the single package any more. The resulting package is too huge and can't easily be uploaded for CI, or be easily moved to other machines. It actually results in more unnecessary modules, plugins and cruft being linked into the Windows Sigil bundle too. Building only the modules that are necessary for Sigil is the only way I can keep my Qt6 environment (not to mention the Sigil installer bundles) small enough to be useful.

I will try an all-in-one build sometime just to rule out the possibility that my methods are causing the slowdown. I just don't see how it could be, though, since the QtWebEngine build alone takes hours and hours. And it uses ninja, which automatically makes use of parallel processing.

[JSWolf]

Originally Posted by DiapDealer

QtWebEngine has always been a mess of a build on Windows. Very memory intensive. A myriad of tiny build tools and libraries that are already available on Linux and Macs need to be compiled first. The list of pre-requisites for building are also ridiculous. Plus there's a massive linking phase at the end of the process where things slow to a complete crawl (even when limiting parallel jobs to avoid maxing out memory usage). Things actually managed to get inexplicably worse when MSVC became fully 64-bit (the tool chain for building 64-bit binaries was actually 32-bit for years).

It's possible that things might work better on Intel, but I don't have the time (or the money) to build a new Windows machine that will literally sit collecting dust between custom Qt builds. Building Qt for Sigil is the only thing I need a physical Windows machine for these days. If not for QtWebEngine's incompatibility, I could probably do better cross-compiling for Windows with MinGW on Linux.

You could get a Micro-PC that has a good processor, 32GB Ram, and a 1TB SSD. They are a lot less expensive then a full size desktop. I bought one with a 12th gen 17 and it was less then $500. It came with Windows 11 Pro.

[KevinH]

Understood. Yes the macdeployqt often includes unnecessary libs. No idea why.

[DiapDealer]

Originally Posted by JSWolf

You could get a Micro-PC that has a good processor, 32GB Ram, and a 1TB SSD. They are a lot less expensive then a full size desktop. I bought one with a 12th gen 17 and it was less then $500. It came with Windows 11 Pro.

I've actually been looking. But anything I would consider a significant upgrade from what I have would be considerably more than $500. I'm not going to waste money on anything less than 128Gb and I9. Plus I'm not convinced the bus speeds on those minis is apples to apples when it comes to the same maxed-out ram/processors on full-size motherboards. I'd also want PCIe M.2 disk speeds.

There's no doubt those minis are great replacements for even high-end general-use PCs. I'm just not convinced they'd be the answer for intensive compilation duties.

[kovidgoyal]

@DiapDealer: FYI, You can build Qt, including web engine just fine using a hardware accelerated qemu Windows VM running under Linux, that's how I do it. Indeed I have mine running in a VM that is actually running on a remote server so that I dont have to bother keeping a powerful machine in house just for this.

[DiapDealer]

Thanks for the idea! I've experimented with qemu in the past, but it's been a while. I've got cores and ram to spare on my main Linux machine. I run plenty of VirtualBox Windows VMs on it, but VBox doesn't do nearly a good enough job of leveraging the underlying hardware for a Qt/WebEngine build (in a reasonable amount of time).

Something really seemed change with Qt6.9 on Windows though. It's taking ridiculously longer to build QtWebEngine than Qt6.8 did on the same hardware.

[kovidgoyal]

Haven't tried building 6.9 yet, it's too buggy to bother. qemu with kvm runs windows with very low overhead. You have to get your qemu parameters right though. It's not the most user friendly of experiences to setup, but once you do it is solid.