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I'm building an LFS 10.1 system on a virtual machine with CPU Intel(R) Core(TM) i5-10210U CPU @ 1.60Hz(yes, it's a laptop) with 2 cores and 4GB of RAM. I'd like to know how long will the build process take. I've finished building gcc and currently running testsuites. I started building gcc from about 2 hours ago. I couldn't use SBUs because it was not accurate in every build. When will the tests finish?

  • just finished gcc tests, and began g++ tests.
mswgen
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1 Answers1

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This question is impossible to answer because:

  • You have not specified how many jobs you're using to build GCC, e.g. just one or -j 8 (a very bad idea considering you're low on RAM, -j 8 requires well over 8GiB of RAM)
  • You have an ultra low power CPU which is unable to actually run at its designated speed when all the cores/threads are busy
  • There's a world of different between building GCC with e.g. -O1 vs -O3 -flto=auto
  • It's not known whether you're building the entire GCC source tree or just C, C++ and LTO backends
  • It's not known whether you're using --disable-stage1-checking or not which could cut the build time by two
  • It's not known whether you're building tests or not

Even for a known CPU which doesn't throttle all the options above could result in compilation times which differ by an order of magnitude or even more.

The i5-10210U CPU has four, not two cores, and eight threads.

I would highly not recommend building GCC on your laptop if you have an SSD disk because its compilation involves writing literally tens of gigabytes of data in terms of temporary files. Nowadays most automated build systems build in tmpfs to speed up compilation and reduce the storage wear and tear.

Artem S. Tashkinov
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  • Well I plan to mainly do it on desktop, which has i5-10400 and 16GB of ram. And I'm building Linux from scratch on a VMware Virtual Machine, which has only 2 cores allocated. The build procrss is run with -j1 and every options are the same as the ones from LFS and all the test suites are run. (I can use desktop only on Saturdays becaude of my mother...) – mswgen Mar 30 '21 at 01:00