Re: [OE-core] [PATCH] rust-llvm: Compile llvm to use dynamic libraries

[Richard Purdie <richard.purdie@linuxfoundation.org>]

[-- Attachment #1: Type: text/plain, Size: 1633 bytes --]

On Mon, 2025-03-31 at 15:08 -0400, Randy MacLeod wrote:
>  
> On 2025-03-31 12:13 p.m., Khem Raj via lists.openembedded.org wrote:
> > On Mon, Mar 31, 2025 at 6:30 AM Richard Purdie via
> > lists.openembedded.org
> > <richard.purdie=linuxfoundation.org@lists.openembedded.org> wrote:
> > > Our main llvm recipe uses dynamic linking already but rust-llvm
> > > does not.
> > > Enabling this significanly reduces the size of llvm-rust to about
> > > a third
> > > of what it was, which is a bettter configuration for us leading
> > > to smaller
> > > TMPDIR and sstate objects
> > > 
> >  
> > 
> >  
> >  
> > It will slow down the compiler execution and sometimes its could be
> > significant as well we have seen this with clang so it would be
> > good to have some idea around that least we provide a slow compiler
> > compared to other distro infrastructures 
> >  
> >  
> >  
>  
> We'll get some performance info from the YP AB perf builds.

https://valkyrie.yocto.io/pub/non-release/20250331-105/testresults/buildperf-debian11/perf-debian12-vk_master-next_20250331181527_9ba5b4f4e4.html
https://valkyrie.yocto.io/pub/non-release/20250331-104/testresults/buildperf-alma8/perf-alma8-vk_master-next_20250331181513_9ba5b4f4e4.html

The build time is fractionally faster (1%?) but hard to say within
noise.

The diskspace drop is convincing, 2.3GB less TMPDIR size (2.3%).

The rm_work TMPDIR size also drops by 1GB (6%) which is particularly
significant and nice to have.

In builds with rust-llvm as well as rust-llvm-native, this will double
up for a double win.

Cheers,

Richard

[-- Attachment #2: Type: text/html, Size: 3125 bytes --]