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ocaml-multicore
domainslib
OCaml2020–2022
ocaml-multicore / domainslib

domainslib

Parallel Programming over Domains

Explore on GitHubRead Hacker News discussions
3Distinct people
5Mentions
0Explicit recommenders
187GitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

Parallel Programming over Domains

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

Mentioned in the same Hacker News threads. That is not proof they are substitutes.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by month5 dated mentions

Observed mentions: 2020-03-31 05:40:47 UTC to 2022-06-15 14:55:14 UTC.

0122020-03-01 00:00:00 UTC to 2020-04-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 commentsMar 20202020-04-01 00:00:00 UTC to 2020-05-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-05-01 00:00:00 UTC to 2020-06-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-06-01 00:00:00 UTC to 2020-07-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-07-01 00:00:00 UTC to 2020-08-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-08-01 00:00:00 UTC to 2020-09-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-09-01 00:00:00 UTC to 2020-10-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-10-01 00:00:00 UTC to 2020-11-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-11-01 00:00:00 UTC to 2020-12-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2020-12-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-01-01 00:00:00 UTC to 2021-02-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-02-01 00:00:00 UTC to 2021-03-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-03-01 00:00:00 UTC to 2021-04-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2021-04-01 00:00:00 UTC to 2021-05-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 commentsApr 20212021-05-01 00:00:00 UTC to 2021-06-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-06-01 00:00:00 UTC to 2021-07-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-07-01 00:00:00 UTC to 2021-08-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-08-01 00:00:00 UTC to 2021-09-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-09-01 00:00:00 UTC to 2021-10-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-10-01 00:00:00 UTC to 2021-11-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-11-01 00:00:00 UTC to 2021-12-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2021-12-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments2022-01-01 00:00:00 UTC to 2022-02-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-02-01 00:00:00 UTC to 2022-03-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-03-01 00:00:00 UTC to 2022-04-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-04-01 00:00:00 UTC to 2022-05-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-05-01 00:00:00 UTC to 2022-06-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2022-06-01 00:00:00 UTC to 2022-07-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 commentsJun 2022

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
Mar 20202020-03-01 00:00:00 UTC2020-04-01 00:00:00 UTC101
Apr 20202020-04-01 00:00:00 UTC2020-05-01 00:00:00 UTC000
May 20202020-05-01 00:00:00 UTC2020-06-01 00:00:00 UTC000
Jun 20202020-06-01 00:00:00 UTC2020-07-01 00:00:00 UTC000
Jul 20202020-07-01 00:00:00 UTC2020-08-01 00:00:00 UTC000
Aug 20202020-08-01 00:00:00 UTC2020-09-01 00:00:00 UTC000
Sep 20202020-09-01 00:00:00 UTC2020-10-01 00:00:00 UTC000
Oct 20202020-10-01 00:00:00 UTC2020-11-01 00:00:00 UTC000
Nov 20202020-11-01 00:00:00 UTC2020-12-01 00:00:00 UTC000
Dec 20202020-12-01 00:00:00 UTC2021-01-01 00:00:00 UTC000
Jan 20212021-01-01 00:00:00 UTC2021-02-01 00:00:00 UTC000
Feb 20212021-02-01 00:00:00 UTC2021-03-01 00:00:00 UTC000
Mar 20212021-03-01 00:00:00 UTC2021-04-01 00:00:00 UTC101
Apr 20212021-04-01 00:00:00 UTC2021-05-01 00:00:00 UTC000
May 20212021-05-01 00:00:00 UTC2021-06-01 00:00:00 UTC000
Jun 20212021-06-01 00:00:00 UTC2021-07-01 00:00:00 UTC000
Jul 20212021-07-01 00:00:00 UTC2021-08-01 00:00:00 UTC000
Aug 20212021-08-01 00:00:00 UTC2021-09-01 00:00:00 UTC000
Sep 20212021-09-01 00:00:00 UTC2021-10-01 00:00:00 UTC000
Oct 20212021-10-01 00:00:00 UTC2021-11-01 00:00:00 UTC000
Nov 20212021-11-01 00:00:00 UTC2021-12-01 00:00:00 UTC000
Dec 20212021-12-01 00:00:00 UTC2022-01-01 00:00:00 UTC202
Jan 20222022-01-01 00:00:00 UTC2022-02-01 00:00:00 UTC000
Feb 20222022-02-01 00:00:00 UTC2022-03-01 00:00:00 UTC000
Mar 20222022-03-01 00:00:00 UTC2022-04-01 00:00:00 UTC000
Apr 20222022-04-01 00:00:00 UTC2022-05-01 00:00:00 UTC000
May 20222022-05-01 00:00:00 UTC2022-06-01 00:00:00 UTC000
Jun 20222022-06-01 00:00:00 UTC2022-07-01 00:00:00 UTC101

What Hacker News says

5 sources
kcsrk·Jun 15, 2022
For nested parallel computations (think Scientific Programming, where one would use OpenMP, Rust Rayon, etc), we have domainslib [1]. Eio, a direct-style, effect-based IO library is pretty competitive against Rust Tokio [2]. The performance will only get better as we get closer to the 5.0 release. [1] https://github.com/ocaml-multicore/domainslib [2] See the http server performance graphs at https://tarides.com/blog/2022-03-01-segfault-systems-joins-t...
In OCaml 5.0 Alpha Release
sadiq·Dec 21, 2021
1. Domains are the unit of parallelism. A domain is essentially an OS thread with a bunch of extra runtime book-keeping data. You can use Domain.spawn (https://github.com/ocaml-multicore/ocaml-multicore/blob/5.00...) to spawn off a new domain which will run the supplied function and terminate when it finishes. This is heavyweight though, domains are expected to be long-running. 2. Domainslib is the library developed alongside multicore to aid users in exploiting parallelism. It supports nested parallelism and is pretty highly optimised (https://github.com/ocaml-multicore/domainslib/pull/29 for some graphs/numbers). The domainslib repo has some good examples: https://github.com/ocaml-multicore/domainslib/tree/master/te... 3. We've not tested against other forms of parallelism. There isn't anything stopping you exploiting SIMD in addition t
Read the rest
o parallelism from domains. 4. No, we've not compared performance by OS. 5. No plans for the multicore team to look at accelerator integration at the moment.
In PR to Merge Multicore OCaml
Zababa·Dec 21, 2021
I've searched a bit for this and haven't been able to find a good answer. Let's say that I have m tasks that I want to run concurrently on n cores, for example handling HTTP requests or searching for something in files. I'd also like to not have to manage manually how the tasks are going to be distributed. Basically, have the same experience as when writing Go code. Is there a way to do this in multicore OCaml? I've found the task pool in domainslib [1] but I'm not sure if it's what I'm looking for. [1]: https://github.com/ocaml-multicore/domainslib/blob/master/li...
In PR to Merge Multicore OCaml
sadiq·Mar 11, 2021
I'm not aware of large standalone projects that depend solely on it. Multicore is backwards compatible with stock OCaml though and 4.12 ships with some stub Atomics (https://github.com/ocaml/ocaml/blob/4.12/stdlib/atomic.mli) which makes writing programs that can work on both easier. We also maintain some projects on top of Multicore that are pretty interesting: * Domainslib - channels and task queue that makes using parallelism via Domains much easier: https://github.com/ocaml-multicore/domainslib * eioio - very much a work in progress but enables high performance direct-style IO with fibers and effects. Backs on to io_uring on Linux and is designed to also work with IOCP on Windows: https://github.com/ocaml-multicore/eioio
In Multicore OCaml: Feb 2021 with new preprint on Effect Handlers
kcsrk·Mar 31, 2020
(I work on Multicore OCaml) Multicore OCaml separates the notion of concurrency (overlapped execution) and parallelism (simultaneous execution). You can have one without the other but also have both. The main principle that we're going for is that the compiler should expose just enough support for concurrency and parallelism such that interesting features can live outside the compiler as libraries. This permits the library evolution not to be tied with the language evolution but also permits diversity of libraries beyond what the language developers can aim to achieve. That said, we will build and maintain a few core libraries for concurrency and parallelism. For concurrency, Multicore OCaml exposes effect handlers [1,2,3] which allows you to build generators, async/await, coroutines, etc as library functions (as opposed to primitives nat
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ively supported by the compiler). For example, have a look at aeio [4] which permits the construction of scalable asynchronous I/O in direct-style (no callbacks). aeio is also discussed in [1]. We also plan to extend Lwt to support parallelism. For parallelism, the compiler exposes Domains, which are a wrapper over OS-threads [5]. Domains expose a low-level API that is not suitable for end user consumption. On top of domains, we support channels with bounded buffers [6] (similar to channels in Go, Mvars in GHC Haskell) as well as software transactional memory (STM) that supports shared memory and message passing concurrency and which can take advantage of hardware transactional memory [7]. [1] Concurrent System Programming with Effect Handlers: http://kcsrk.info/papers/system_effects_feb_18.pdf [2] CUFP effects tutorial: https://github.com/ocamllabs/ocaml-effects-tutorial [3] Effects Examples: https://github.com/kayceesrk/effects-examples [4] Aeio: Asynchronous Effect-based IO https://github.com/kayceesrk/ocaml-aeio [5] Domains: https://github.com/ocaml-multicore/ocaml-multicore/blob/para... [6] domainslib: https://github.com/ocaml-multicore/domainslib [7] Reagents: https://github.com/ocaml-multicore/reagents
In Multicore OCaml: March 2020 update

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