libthread 1:1 threads

Julian Elischer julian at
Fri Apr 22 12:43:02 PDT 2005

David Leimbach wrote:

>Perhaps David Xu could clue me in a bit more :)
>I just got around to reading the status report for FreeBSD and the 1:1
>threading caught my eye.
>I'm not terribly familiar with FreeBSD's KSE based threading but
>rather than adding a new system call [which may be ok... though I've
>worked on systems where a minimal set of system calls is the desired
>approach.. usually microkernels] would it be possible to add KSEs to a
>task using rfork()?

KSE and 1:1 threading are different things.
One creatres kernel threads on demand and the other keeps the kernel
threads all the time the user thread exists.

rfork is not the same.. it creates a new process context. that is what 
Linux does.
it is also what we did before when running the the linuxthreads package.

KSE and 1:1 use a lot of the same kernel changes and entities.
Which one survives will be  judged in time.

>Maybe I've just been playing around with Plan 9 too much lately :)
>Anyway, I like that there will be a 1:1 threading library and if I had
>more free time and wasn't working on other projects I'd be more than
>willing to help test and work on/with this.

there has been a 1:1 and an M:N library since 5.2

>Still, very very cool :)
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