Show HN: uThreads – Concurrent User Threads in C and C++
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Show HN: uThreads – Concurrent User Threads in C and C++
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Re: Show HN: uThreads – Concurrent User Threads in C and C++
#2Interesting, I've recently been looking for a user level threading package in C/C++. I ended up settling on lthreads: http://lthread.readthedocs.io/en/latest/intro.html
Does anyone know how it compares?
Re: Show HN: uThreads – Concurrent User Threads in C and C++
#3Interesting, I've recently been looking for a user level threading package in C/C++. I ended up settling on lthreads: http://lthread.readthedocs.io/en/latest/intro.html Does anyone know how it compares?
I haven't tried either but I've been meaning to take a look at https://github.com/Amanieu/asyncplusplus.
Re: Show HN: uThreads – Concurrent User Threads in C and C++
#4Interesting, I've recently been looking for a user level threading package in C/C++. I ended up settling on lthreads: http://lthread.readthedocs.io/en/latest/intro.html Does anyone know how it compares?
Hi, I developed uThreads. I looked at lthreads quickly, and it seems lthreads only maps multiple coroutines onto a single pthread (N:1). Although, it adds the possibility of running multiple pthreads, but each pthread can only run their local lthreads (using M threads that do N:1 mapping). However, in uThreads, uThreads can be multiplexed over multiple pthreads (thus M:N mapping).
Also lthreads scheduler is based on epoll/kqueue per pthread, and uThreads is using run Queues to manage uThreads which has less overhead. Per pthread epoll/kqueue can mean better scalability for large number of threads in comparison with uThreads that is relying on a single poller thread. But since the poller thread and synchronization is very low overhead in uThreads, the scalability is not an issue (Experiments to up to 16 threads show that uThreads scale very well).
Although lthreads provide compute boundaries and async IO to move lthreads over other pthreads, but this process seems to be very expensive. uThreads does not provide these features, but it provides more flexibility and control to the developer by providing migrations. Developers can use migration at any point to move the uThread to another set of kThreads to execute tasks asynchronously (By defining Clusters of kThreads, e.g., IO cluster or Compute Cluster).
Re: Show HN: uThreads – Concurrent User Threads in C and C++
#5[deleted]
Re: Show HN: uThreads – Concurrent User Threads in C and C++
#6This looks super interesting! I've been working on a Raytracer in C++ and I was recently looking into a threading library which I can use to parallelize the rendering. Surely going to try this out in the coming weekend.
Unsolicited suggestion - while benchmarks and the motivation are important for a threading library, a code snippet of a simple parallel program on the home page would be something that I'd love to see.
Great job, though!
Re: Show HN: uThreads – Concurrent User Threads in C and C++
#7This looks super interesting! I've been working on a Raytracer in C++ and I was recently looking into a threading library which I can use to parallelize the rendering. Surely going to try this out in the coming weekend. Unsolicited suggestion - while benchmarks and the motivation are important for a threading library, a code snippet of a simple parallel program on the home page would be something that I'd love to see…
Thanks! good point; now that I look at the page, there is not a single sample code in there. I'll update it soon.
Re: Show HN: uThreads – Concurrent User Threads in C and C++
#8This looks super interesting! I've been working on a Raytracer in C++ and I was recently looking into a threading library which I can use to parallelize the rendering. Surely going to try this out in the coming weekend. Unsolicited suggestion - while benchmarks and the motivation are important for a threading library, a code snippet of a simple parallel program on the home page would be something that I'd love to see…
Thanks! good point; now that I look at the page, there is not a single sample code in there. I'll update it soon.
Awesome! As an example, Rayon[0] does a very good job (IMHO) at this.
Re: Show HN: uThreads – Concurrent User Threads in C and C++
#9Impressive.
8KiB stacks are a bit on the small side though for production usage. Go gets away with this because they're stacks act more like Vectors then flat arrays.
Why did you decided to roll your own stack swapping software instead of using say using `boost::context`?
Re: Show HN: uThreads – Concurrent User Threads in C and C++
#10Impressive. 8KiB stacks are a bit on the small side though for production usage. Go gets away with this because they're stacks act more like Vectors then flat arrays. Why did you decided to roll your own stack swapping software instead of using say using `boost::context`?
Right, however segmented stacks are have high overhead and stack copying is not very easy in C/C++. Thus, for now uThreads only support fixed size stacks, I know it makes it harder to be used in production, and in the future I might provide optional segmented stacks.
As for why not using `boost::context`, I am implementing uThreads as part of my research in uwaterloo, I wanted to have full control over the code and be able to optimize for performance as much as I can. Thus, tried to avoid relying on any third party code when I started :)