Building Qt5.15.2 on Ubuntu 18.04 takes too long

Fantastic Mr. Fox

I'm trying to build Qt5 from the source code, but it takes ages on my 32-bit Ubuntu - more then a week and it's still not completed?!

All I can see is the ninja command w/ parameter -v .../qtwebengine/src/core/release QtWebEngineCode
ninja: Entering directory .../release

Is there any option, so I can see what's compiling at the moment?? Ta

mrjj

Hi
A week is too long. even on a very low-end pc.
It sounds like its went into some sort of loop.

what are your pc specs ? CPU / cores and amount of ram.

Fantastic Mr. Fox

It's prety old notebook Asus X51R: Intel 1.86GHz, 2 cores, 1.5GB RAM.
Configure log
Make output

mrjj

Hi
Ok that is a pretty old one :)
I would have thought 1.5GB would be too little but maybe virtual mem is
helping it.
Reading over the logs a few times. I don't really see anything repeating.
However, I think it would never have been completed anyway as even on small boards it
"just" took 1.5 days to compile so over a week still seems unreasonable.

Is there a reason you compile on this "not so much a workstation" pc ?

Fantastic Mr. Fox

Well, it's definitely memory issue - ninja file is too large (28 MB) plus all subninja files..

Now I have different problem : I can't find files in chromium folder. Why?

ninja: error: '../../../../../qtwebengine/src/3rdparty/chromium/v8/test/fuzzer/fuzzer.cc', needed by 'obj/v8/v8_simple_json_fuzzer/fuzzer.o', missing and no known rule to make it

The folder chromium/v8/test/fuzzer is empty. There is no source file except BUILD.gn. Any idea??

@mrjj said in Building Qt5.15.2 on Ubuntu 18.04 takes too long:

Is there a reason you compile on this "not so much a workstation" pc ?

I just want to avoid dependency hell, so I think that it's better when I compile Qt from source on this Abacus.

Fantastic Mr. Fox

Note however the build process will launch a ninja build-system nested, you can override the ninja flags with the environment variable NINJAFLAGS before configuring or append to them with NINJAJOBS after configuring. This is for instance useful if you use icecc, or your machine does not have enough memory to run the default number of ninja threads with the often very memory intensive chromium sources (2-3Gbyte per thread).

source

JKSH

@Fantastic-Mr-Fox said in Building Qt5.15.2 on Ubuntu 18.04 takes too long:

I just want to avoid dependency hell, so I think that it's better when I compile Qt from source on this Abacus.

It's better to create a virtual machine on a powerful PC and install a fresh OS which has no Qt in it. It can be an old OS, but you need decent hardware to finish the job, espicially if you're compiling Qt WebEngine (Chromium).

You can get away with a weaker PC if you skip Qt WebEngine.

From the official Chromium docs (emphasis added): https://chromium.googlesource.com/chromium/src/+/refs/heads/main/docs/linux/build_instructions.md#System-requirements

System requirements

A 64-bit Intel machine with at least 8GB of RAM. More than 16GB is highly recommended.

At least 100GB of free disk space.

Fantastic Mr. Fox

You're right. I installed Debian 11 OS (which offers 32 bit version of Qt5.15.2) on different machine (1TB HDD etc). Thanks for the answers..