Raspberry Pi4B 8GB EMERGE_DEFAULT_OPTS

Message

n1ese · Post by **n1ese** » Mon Jun 13, 2022 10:48 pm

What would be good --jobs and --load-average settings be for EMERGE_DEFAULT_OPS on a Raspberry Pi4B with 8GB of RAM.

Today, I emerged x11-base/xorg-server and x11-terms/xterm. Two of the dependices called for two different versions of sys-devel/llvm and it emerged them both at the same time:

Code: Select all

>>> Emerging (66 of 75) sys-devel/llvm-13.0.1::gentoo
>>> Emerging (67 of 75) sys-devel/llvm-14.0.4::gentoo

It took over 8 hours to emerge both at the same time and I was really surprised it took so long. The entire time, my system was running with a load average over 8. Is compiling LLVM really this taxing? I'm also surprised two different versions were requested/needed.

My make.conf:

Code: Select all

MAKEOPTS="-j4"
EMERGE_DEFAULT_OPTS="--jobs 4 --load-average 3.7"

Leonardo.b · Post by **Leonardo.b** » Mon Jun 13, 2022 11:13 pm

In my opinion, you should not compile more packages in parallel.

n1ese · Post by **n1ese** » Tue Jun 14, 2022 12:37 am

Leonardo.b wrote:In my opinion, you should not compile more packages in parallel.

yeah, thinking a couple guides I read lead me astray.

Post by Hu » Tue Jun 14, 2022 1:13 am

The typical advice I see is to allocate 2GB RAM per job. By that rule, you need 4 * 4 * 2GB = 32GB RAM on this device for your current settings.

To see why you need 2 versions of LLVM, we would need to see the output of emerge --tree --verbose before you installed them. You might be able to answer this now by checking emerge --pretend --verbose --depclean sys-devel/llvm. I would expect that emerge --ask --verbose x11-base/xorg-server x11-terms/xterm should have informed you that 2 LLVM versions were scheduled.

n1ese · Post by **n1ese** » Tue Jun 14, 2022 1:21 am

Hu wrote:To see why you need 2 versions of LLVM, we would need to see the output of emerge --tree --verbose before you installed them. You might be able to answer this now by checking emerge --pretend --verbose --depclean sys-devel/llvm. I would expect that emerge --ask --verbose x11-base/xorg-server x11-terms/xterm should have informed you that 2 LLVM versions were scheduled.

Code: Select all

ganymede ~ # emerge --pretend --verbose --depclean sys-devel/llvm

Calculating dependencies... done!
  sys-devel/llvm-13.0.1 pulled in by:
    media-libs/mesa-22.0.3 requires <sys-devel/llvm-14:=, <sys-devel/llvm-14:13/13=, sys-devel/llvm:13

  sys-devel/llvm-14.0.4 pulled in by:
    sys-devel/llvmgold-14 requires sys-devel/llvm:14[binutils-plugin]

Post by Hu » Tue Jun 14, 2022 2:40 pm

That provides the immediate answer. llvmgold brought in the newer version. mesa brought in the older one. You could optionally add those to the command if you want to dig deeper and understand why each of them are needed.

n1ese · Post by **n1ese** » Tue Jun 14, 2022 3:40 pm

Hu wrote:That provides the immediate answer. llvmgold brought in the newer version. mesa brought in the older one. You could optionally add those to the command if you want to dig deeper and understand why each of them are needed.

Yeah, I'm starting to become more confused.

Code: Select all

emerge --pretend --verbose --depclean sys-devel/llvmgold

Calculating dependencies... done!
  sys-devel/llvmgold-14 pulled in by:
    sys-devel/llvm-13.0.1 requires >=sys-devel/llvmgold-13
    sys-devel/llvm-14.0.4 requires >=sys-devel/llvmgold-14

Post by Hu » Tue Jun 14, 2022 4:15 pm

Mesa caused you to need llvm-13. llvm-13 needed any recent llvmgold. The most recent llvmgold is llvmgold-14, which is acceptable to llvm, so it was installed. Once you needed llvmgold-14, then you also needed llvm-14.

n1ese · Post by **n1ese** » Tue Jun 14, 2022 4:40 pm

Hu wrote:Mesa caused you to need llvm-13. llvm-13 needed any recent llvmgold. The most recent llvmgold is llvmgold-14, which is acceptable to llvm, so it was installed. Once you needed llvmgold-14, then you also needed llvm-14.

Gotcha, makes sense now, thanks.