[llvm-dev] Concurrent Hashmap?

[Neil Henning via llvm-dev]

Just because it wasn't totally clear to me - is this about having a single
LLD process have better parallelism?

What we'd love is that we could use LLD as a library (to save on process
launch cost) multithreaded, but last I checked there was still lots of
globals used all over the place.

Cheers,
-Neil.

On Thu, Apr 8, 2021 at 2:05 PM Alexandre Ganea via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> When you say you'd like to parallelize LLD, which driver do you mean?
> COFF, ELF, wasm...? They all have separate codebases.
>
> There's already a specialized lock-free hashtable for the Debug Types
> merging the COFF driver:
> https://github.com/llvm/llvm-project/blob/e7a371f9fd0076c187f4cd1a9c7546867faeb19b/lld/COFF/DebugTypes.cpp#L992
>
>
> I'd be really interested to hear what kind of design you had in mind for
> the concurrent hashmap?
>
> If you contribute any concurrent container into ADT, I'd like to see an
> application along (that is, a patch that uses the container in LLD for
> example). If the container is used in a tight loop, it needs to be
> lock-free if we want it to scale on many-core machines. And in that case
> we're pretty much limited to a 64-bit key/value pair if we don't want to
> make things complicated. We could also have a sharded container that would
> fit more cases, but tweaking it really depends on its usage.
>
> -----Message d'origine-----
> De : llvm-dev <llvm-dev-bounces at lists.llvm.org> De la part de Jez via
> llvm-dev
> Envoyé : April 7, 2021 5:16 PM
> À : llvm-dev at lists.llvm.org
> Objet : [llvm-dev] Concurrent Hashmap?
>
> I'm looking into parallelizing LLD, and one of the things that would
> probably help is a concurrent hashmap. I was unable to find an existing
> implementation under ADT/, which was somewhat surprising.
> Should I contribute an implementation?
>
> Jez
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>


-- 
Neil Henning
Senior Software Engineer Compiler
unity.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20210408/3c3d4070/attachment.html>