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On Fri Mar 13, 2026 at 7:02 AM CET, Sundeep KOKKONDA via lists.openembedded.org wrote:

From: Sundeep KOKKONDA <sundeep.kokkonda@windriver.com>

Enabled the parallel-frontend-threads for faster compilation of rust code.

Test Results:
A few tests (bitbake rust) ran by with and without enabling this option.
- Machine config: Intel(R) Xeon(R) CPU E5-4669 v3 @ 2.10GHz with 144 CPUs.
- Avg. default build time (w/o this option) - 56m 50.104s
- Avg. build time with this option - 49m 17.224s
- Performance Difference - 7m 32.880s faster builds (≈ 13.3%)

parallel-frontend-threads is limited to a max of 8 for best results.
More info - https://blog.rust-lang.org/2023/11/09/parallel-rustc/

Signed-off-by: Sundeep KOKKONDA <sundeep.kokkonda@windriver.com>
---

Hi Sundeep,

It looks like this is causing some reproducibility issues:

AssertionError: The following deb packages are different and not in exclusion list:
/srv/pokybuild/yocto-worker/reproducible/build/build-st/reproducibleB-extended/tmp/deploy/deb/./x86-64-v3/rust-dbg_1.94.0-r0_amd64.deb
/srv/pokybuild/yocto-worker/reproducible/build/build-st/reproducibleB-extended/tmp/deploy/deb/./x86-64-v3/rust_1.94.0-r0_amd64.deb
The following ipk packages are different and not in exclusion list:
/srv/pokybuild/yocto-worker/reproducible/build/build-st/reproducibleB-extended/tmp/deploy/ipk/./x86-64-v3/rust-dbg_1.94.0-r0_x86-64-v3.ipk
/srv/pokybuild/yocto-worker/reproducible/build/build-st/reproducibleB-extended/tmp/deploy/ipk/./x86-64-v3/rust_1.94.0-r0_x86-64-v3.ipk
The following rpm packages are different and not in exclusion list:
/srv/pokybuild/yocto-worker/reproducible/build/build-st/reproducibleB-extended/tmp/deploy/rpm/./x86_64_v3/rust-1.94.0-r0.x86_64_v3.rpm
/srv/pokybuild/yocto-worker/reproducible/build/build-st/reproducibleB-extended/tmp/deploy/rpm/./x86_64_v3/rust-dbg-1.94.0-r0.x86_64_v3.rpm

Diffoscope output is here:
https://valkyrie.yocto.io/pub/repro-fail/oe-reproducible-20260313-gl43mwtc/packages/diff-html/

Can you have a look at it?

Hello,

I am able to reproduce the issue. I see the librustc_driver-3a7e57d3c38387b5.so has changed between the builds. The 'BuildID' is different in both .so files which is happening due to a difference in .gnu_debuglink section.

I am further analyzing how this option is affecting this section.

Thanks,

Sundeep K.

Thanks,
Mathieu

--
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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