shameless plug: lld 23.x is significantly faster than 22.x! I wrote about the optimizations in https://maskray.me/blog/2026-04-12-recent-lld-elf-performanc...
As a side note, parallel input file parsing and symbol resolution aren't a silver bullet. I have an experimental branch (net ~800 lines of code) adding this to lld/ELF, but it actually loses performance when restricted to --threads={1,2}
I read how mold implements parallel input file parsing a while ago. It is overly complicated. wild's model seems superior.
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"Table 4." in the paper feels misleading to me. I have never measured such high speedups. In addition, on debug builds (especially --gdb-index builds), mold's edge over lld is smaller.
On ICF, some unknown fraction of mold's speedup is due to "doesn't do the symbol bootkeeping". The symbol tables are different in mold but identical in lld.
Here's a lwn.net link to Ian Lance Taylor's blog posts about his gold linker (his blog doesn't seem to have any table of contents or group the linker-related blog posts in one area/tag).
But back in the late 2000s, the blog posts were a combination of algorithm optimization class and software history since no one seemed to step up to cleanup the technical debt that GNU ld had accumulated over the decades.
> my strategy is to increase the value of commons by, say, 100 and get 1 as a return, so bear with me. If you want to use mold for free, you can just do that. This is my open-source business strategy.
> so do most of the servers except the most popular 2
Are you sure? All three servers I regularly use, as well as all of the mirrors that I found with a quick search, are down. If there are other servers still working then can you please give a hint about how I could find them?
This is a wonderful paper that includes many optimization tricks that are generally applicable, including various optimizations that they retrofitted into lld. But I thought there was one meta optimization that was especially interesting (from page 2):
> A new linker's early adopters knowingly accept such differences, which is one reason why drastic improvements tend to come from new linkers rather than existing ones
This is true of many things, not just linkers. I think this is encouraging for people to (re)try things that have already been done, because newcomers are allowed to take risks that established things can't take.
I use mold a lot for code embedding in my lisp. I needed extra null PHT entries in the ELF so I could easily patch in custom segments into the interpreter after the link was done.
GNU pretty much ignored the feature request and LLVM probably never even saw the issue, but Rui shipped the --spare-program-headers feature pretty much immediately after I requested it and it immediately restored my sanity.
Current version of my patcher supports ld and lld, but it has to move the PHT to the end of the file in order to append the new segments. Mold is still the only way to avoid the ugly hole where the PHT used to be.
I'm keen to follow along with Wild as their intent is to be incremental, and Zig recently announced incremental linking support. I'm also a fan as its cool to seen an Australian working full time on open source (I'm also Australian)
Edit to add: I think David's talk on Wild [0] is an interesting summary of what a linker is and why its hard to make incremental
I read how mold implements parallel input file parsing a while ago. It is overly complicated. wild's model seems superior.
---
"Table 4." in the paper feels misleading to me. I have never measured such high speedups. In addition, on debug builds (especially --gdb-index builds), mold's edge over lld is smaller.
On ICF, some unknown fraction of mold's speedup is due to "doesn't do the symbol bootkeeping". The symbol tables are different in mold but identical in lld.
see https://lwn.net/Articles/276782/
GNU gold is deprecated and will probably be removed soon. ( https://www.phoronix.com/news/GNU-Gold-Linker-Deprecated )
But back in the late 2000s, the blog posts were a combination of algorithm optimization class and software history since no one seemed to step up to cleanup the technical debt that GNU ld had accumulated over the decades.
(https://x.com/rui314/status/1560277403787997185)
> my strategy is to increase the value of commons by, say, 100 and get 1 as a return, so bear with me. If you want to use mold for free, you can just do that. This is my open-source business strategy.
Wishing the best for Mold and Rui
Are you sure? All three servers I regularly use, as well as all of the mirrors that I found with a quick search, are down. If there are other servers still working then can you please give a hint about how I could find them?
> A new linker's early adopters knowingly accept such differences, which is one reason why drastic improvements tend to come from new linkers rather than existing ones
This is true of many things, not just linkers. I think this is encouraging for people to (re)try things that have already been done, because newcomers are allowed to take risks that established things can't take.
I use mold a lot for code embedding in my lisp. I needed extra null PHT entries in the ELF so I could easily patch in custom segments into the interpreter after the link was done.
GNU pretty much ignored the feature request and LLVM probably never even saw the issue, but Rui shipped the --spare-program-headers feature pretty much immediately after I requested it and it immediately restored my sanity.
https://www.matheusmoreira.com/articles/self-contained-lone-...
Current version of my patcher supports ld and lld, but it has to move the PHT to the end of the file in order to append the new segments. Mold is still the only way to avoid the ugly hole where the PHT used to be.
https://github.com/wild-linker/wild
(Benchmarks in the README.)
Edit to add: I think David's talk on Wild [0] is an interesting summary of what a linker is and why its hard to make incremental
[0] https://www.youtube.com/watch?v=WSHt3-gwVxc
Seems that some optimizations went to mold 2.42 and others are not yet released. Wild benchmarked mold 2.40 or 2.41