[9fans] Why is the tcp/ip stack of plan9 implemented in kernel?

[9fans] Why is the tcp/ip stack of plan9 implemented in kernel?

[lchg]

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 In plan9, many os components are moved to user space, even disk file
system. But the tcp/ip stack is an exception, what's the consideration for
this? Just for performance, or some other reasons?
And is there a relatively easy solution to move the stack to user space?

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Re: [9fans] Why is the tcp/ip stack of plan9 implemented in kernel?

[FJ Ballesteros]

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VSTa had a design heavily inspired by 9 and had the net stack at user level. 
It was fun to play with it, long ago. 

> El 27 ene 2018, a las 8:04, lchg <lchg567@gmail.com> escribió:
> 
> In plan9, many os components are moved to user space, even disk file system. But the tcp/ip stack is an exception, what's the consideration for this? Just for performance, or some other reasons?
> And is there a relatively easy solution to move the stack to user space?
> 

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Re: [9fans] Why is the tcp/ip stack of plan9 implemented in kernel?

[Steve Simon]

in early versions of plan9 the tcp/ip stack in Streams, inherited (I assume) from V10.

This turned out not to be as clean nor as efficent as hoped and this was dropped
for a more traditional implementation in later releases. Maybe the bad experiences
of poor performance informed the decision for an in-kernel implementation?

-Steve

[9fans] Why is the tcp/ip stack of plan9 implemented in kernel?

[Nick Owens]

it used to be in userspace, but i believe it was moved to the kernel
for performance reasons.

the remaining evidence of the ip stack in the kernel lives on in (at
least) 9front's sysproc.c, where sysexec raises the process priority
if the program is "/ip", which i assume would be the tcp/ip stack
binary embedded in the kernel image's devroot (not the paqfs):

/*
*  '/' processes are higher priority (hack to make /ip more responsive).
*/
if(devtab[tc->type]->dc == L'/')
up->basepri = PriRoot;

On Sat, Jan 27, 2018 at 1:45 AM, Steve Simon <steve at quintile.net> wrote:
> in early versions of plan9 the tcp/ip stack in Streams, inherited (I assume) from V10.
>
> This turned out not to be as clean nor as efficent as hoped and this was dropped
> for a more traditional implementation in later releases. Maybe the bad experiences
> of poor performance informed the decision for an in-kernel implementation?
>
> -Steve
>