user defined lto rust based build packages

[CaptainBlood]

Just succeeded lto-fat user defined built.
-10.92% binray shrink gui-apps/eww::guru

Build has big ram use though low on ressources here.
More tests required before publishing on how 2.

Thks 4 ur attention, interest & support.

[CaptainBlood]

Another one with -11.04 media-sound/helvum

Thks 4 ur attention, interest & support

[CaptainBlood]

Ouch +0.11 this time, building still app-shells/mcfly

Thks 4 ur attention, interest & support.

[CaptainBlood]

Okay,
It's all about adding the following to RUSTFLAGS:

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-Clto=fat
-Cembed-bitcode=yes

packages referencing proc-macro* crates also require

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-Zdylib-lto

here.
rust compiler requires it when needed.

Achieved with

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dev-lang/rust
     Installed versions:  1.77.1(stable/1.77)^t(08:53:51 15/04/2024)(clippy doc miri nightly profiler rust-analyzer rust-src rustfmt system-bootstrap verify-sig wasm -big-endian -debug -dist -llvm-libunwind -lto -parallel-compiler -system-llvm -test ABI_MIPS="-n32 -n64 -o32" ABI_S390="-32 -64" ABI_X86="64 -32 -x32" CPU_FLAGS_X86="sse2" LLVM_TARGETS="WebAssembly X86 -AArch64 -AMDGPU -ARC -ARM -AVR -BPF -CSKY -DirectX -Hexagon -Lanai -LoongArch -M68k -MSP430 -Mips -NVPTX -PowerPC -RISCV -SPIRV -Sparc -SystemZ -VE -XCore -Xtensa")

Plz note some packages already have lto directive; some will have their size increased when adding as described above (e.g. sys-apps/fd)

Thks 4 ur attention, interest & support

[CaptainBlood]

gui-wm/niri::guru gains 14.27% here.

Thks 4 ur attention, interest & support.

[CaptainBlood]

sys-apps/fd has tiny .1% size gain

Thks 4 ur attention, interest & support.

[CaptainBlood]

app-containers/aardvark-dns has a nice 18% shrink

Thks 4 ur attention, interest & support.

[Zucca]

Have you measured compilation time and ram usage with these optimizations on and off?

And say, for example helvum, how much in bytes you save on disk?

I guess performance gains vary greatly between programs? ... If it's even measurable.

[CaptainBlood]

Have you measured compilation time and ram usage with these optimizations on and off?

No I'm focusing on binary size only.

Time shouldn't be 2 difficult to get.
No idea how to deal with compilation ram usage.
Tips welcome.

And say, for example helvum, how much in bytes you save on disk?

About 12.51% size shrink.

I guess performance gains vary greatly between programs? ... If it's even measurable.

No idea. Focusing on ram/disk savings.

Side note: jcc bug compensation here, which adds bytes on both sizes, expected to be of comparable amounts.
This jcc lowers the %.

Thks 4 ur attention, interest & support.

[Zucca]

And say, for example helvum, how much in bytes you save on disk?

About 12.51% size shrink.

... and in bytes?

[CaptainBlood]

And say, for example helvum, how much in bytes you save on disk?

About 12.51% size shrink.

... and in bytes?

------------------
jcc mitigation:
lto no:
-rwxr-xr-x 1 root root 1104400 août 1 22:53 /usr/bin/helvum
lto:
-rwxr-xr-x 1 root root 981520 août 1 21:03 /usr/bin/helvum

size gain: (1104400-981520)*100/981520=12.51%
----------------------
jcc no mitigation:
lto no:
-rwxr-xr-x 1 root root 1092112 août 1 23:10 /usr/bin/helvum
lto:
-rwxr-xr-x 1 root root 961040 août 2 00:03 /usr/bin/helvum

size gain: (1092112-961040)*100/961040=13.63%

[Zucca]

Seems like not worth for me.

Maybe for some SBC or embedded system at some corner cases. Of if I'd want to shrink my initramfs, which does not contain any rust packages at the moment anyways.

[CaptainBlood]

Seems like not worth for me.

Maybe for some SBC or embedded system at some corner cases. Of if I'd want to shrink my initramfs, which does not contain any rust packages at the moment anyways.

Sounds like your mind was made already, i.e. before my last post.

Side note:
At least rust build packages resulting in standalone static binaries may be good candidates for app-arch/upx compression.
Here are the numbers for the package you seemed concerned about:

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acer /usr/bin # upx --ultra-brute helvum
                       Ultimate Packer for eXecutables
                          Copyright (C) 1996 - 2024
UPX 4.2.3       Markus Oberhumer, Laszlo Molnar & John Reiser   Mar 27th 2024

        File size         Ratio      Format      Name
   --------------------   ------   -----------   -----------
    961040 ->    324620   33.78%   linux/amd64   helvum

Thks 4 ur attention, interest & support.

[Zucca]

I'm not really interested in any particular package. I'm just gathering some info for the future.
I've been putting together some initramfs based live environments (for rescue, file copying, dignostics). Size matter there when you have only, say, 2GB of RAM.

Still at the planning stage.

[CaptainBlood]

Very out of topic:8)

initramfs...

Still at the planning stage here for more than decade...
The main purpose I feel its need would be disk encryption...
But still feel very uncomfortable about how to & recovery.

Thks 4 ur attention, interest & support.

[CaptainBlood]

First case where lto is bigger:

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lto-no: -rwxr-xr-x 1 root root 11650080 août   6 00:08 /usr/bin/broot
lto:    -rwxr-xr-x 1 root root 11699232 août   6 00:22 /usr/bin/broot

Thks 4 ur attention, interest & support.

[CaptainBlood]

-rwxr-xr-x 1 root root 961040 août 2 00:03 /usr/bin/helvum

rust 1.80.1 instead of 1.79.0 is improving:

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-rwxr-xr-x 1 root root 932080 août  15 14:57 /usr/bin/helvum

Thks 4 ur attention , interest & support.

[CaptainBlood]

app-shells/nushell is another one with 18.79% size decrease.

Thks 4 ur attention, interest & support.