Re: [9fans] critique of sockets API

[erik quanstrom <quanstro@quanstro.net>]

On Tue Jun  9 14:50:58 EDT 2009, bpisupat@cs.indiana.edu wrote:
> Interesting read:
> http://cacm.acm.org/magazines/2009/6/28495-whither-sockets/fulltext
>
> If I am right, the filesystem based networking interface offered by Plan 9
> has the three limitations discussed here:
> * performance overhead: app requesting data from a socket typically needs
> to perform 2 system calls (select/read or alt/read)

alt — which is not required — is not a system call.  only a read or write is
required.

> * lack of an "kernel up-call API": which allows the kernel to inform an
> app each time network data is available

plan 9 uses synchronous i/o, so this statement doesn't make sense
in plan 9.  you can use threads to do i/o asynch w.r.t. your application,
but the i/o itself is still synchronous w.r.t. the kernel.

> * hard to implement "multi homing" with support for multiple network
> interfaces

i have no idea how this relates to the use of a fs in implementing the
network stack.  why would using a filsystem (or not) make any difference
in the ability to multihome?

by the way, plan 9 beats the pants off anything else i've used for multiple
network / interface support.  it's support for mulitple ip stacks is quite
neat.

- erik