Re: llvm10 build failure on Rpi3

From: Denis Ovsienko <>
Date: Wed, 23 Jun 2021 19:19:20 +0100
On Wed, 23 Jun 2021 10:43:38 -0700
bob prohaska <> wrote:

> A Pi4 doing a bulk build of chromium, lxqt and apache has gone far
> past that point building llvm10, suggesting the fault lies somewhere
> in my setup.

In case this information helps, I occasionally build Clang/LLVM on
NetBSD/AArch64. When trying to do that directly on the RPI3B, the main
difficulty was that cc1plus process typically grows 500-700MB big before
it produces an .o file, so instead of -j4 it had to run -j1 to avoid
swapping (1GB RAM). What's worse, for some files the process size
reached 1500MB anyway, and the incurred swapping was effectively
blocking any progress.

After waiting a week for the build to finish I spawned another NetBSD
in a Cortex-A53 QEMU VM. The emulated CPU core performance measured at
40% the RPI3 CPU core performance in my [rather crude] test, but this
way you can emulate as many cores and as much RAM as the host system
can provide. In my case 4 cores and 8GB of emulated RAM were enough to
build both LLVM and Clang in acceptable time. The resulting packages
install and work on RPI3B as expected.

As far as I understand, much of this logic should apply to FreeBSD as
well. Could you please confirm if any resources were maxing out during
the failed build on RPI3B?

    Denis Ovsienko
Received on Wed Jun 23 2021 - 18:19:20 UTC

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