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CadQuery / ocp-build-system

A system to build Python wheel PyPI packages for OCP.
Apache License 2.0
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Strip OCP.so for smaller installed footprint #33

Closed fischman closed 1 month ago

fischman commented 4 months ago

pip install build123d leads to an OCP.cpython-310-x86_64-linux-gnu.so sized 242MiB. Running strip on that .so reduces it to 143MiB, and all the cadquery and build123d tests still pass. See details on discord, as well as a motivation for this (service provider imposed limits on image size.

Could the OCP .so be stripped before inclusion in the wheel? (possibly here though I've just skimmed the repo)

jmwright commented 3 months ago

@fischman Is there log output from when you ran the strip command which shows what is being done to the .so file? I'm hesitant to do this in CI without a better understanding of what it is doing to the lib file.

fischman commented 3 months ago

@jmwright

Is there log output from when you ran the strip command which shows what is being done to the .so file?

No; strip is silent by default. When given -v it emits something like copy from/tmp/OCP.cpython-310-x86_64-linux-gnu.so' [elf64-x86-64] to /tmp/stGEw0qJ' [elf64-x86-64] but IDK that that's useful.

I'm hesitant to do this in CI

Possibly debian's guidance will increase confidence https://www.debian.org/doc/debian-policy/ch-files.html#shared-libraries:~:text=All%20installed%20shared%20libraries%20should%20be%20stripped%20with

a better understanding of what it is doing to the lib file.

In terms of ELF sections, this shows that the .comment, .strtab, and .symtab sections are removed:

$ for suffix in before after; do l="OCP.cpython-310-x86_64-linux-gnu.so.$suffix"; ls -l $l; readelf --sections $l | sed -ne 's/^ *\[[ 0-9]*\] *\([^ ]*\) .*/\1/p'|sort > sections.$suffix; done; diff sections.before sections.after
.rwxrwxr-x 249M ami 13 Aug 15:36 OCP.cpython-310-x86_64-linux-gnu.so.before
.rwxrwxr-x 144M ami 13 Aug 15:37 OCP.cpython-310-x86_64-linux-gnu.so.after
2d1
< .comment
26,27d24
< .strtab
< .symtab

(the above is using debian's recommended flags: strip --strip-unneeded --remove-section=.comment --remove-section=.note)

readelf --sections on the "before" lib shows the sections account for: .comments is 84 bytes, .symtab is 11,309,856 bytes, and .symtab is 90,439,979 bytes.

Happy to answer any other questions I can.

jmwright commented 2 months ago

We can discuss targeting 7.8.1 for this. A PR to add this to CI and the local build scripts would be welcome.

fischman commented 2 months ago

@jmwright https://github.com/CadQuery/ocp-build-system/pull/38 has a first crack at this. I was mostly guessing as to how this repo works :)

jmwright commented 1 month ago

Fixed by @fischman in #38