Re: [PATCH 2 of 4] Introduce i386 fibril scheduling

[Davide Libenzi <davidel@xmailserver.org>]

On Mon, 5 Feb 2007, Zach Brown wrote:

> > The normal and most optimal workflow should be a user-space ring-buffer
> > of these constant-size struct async_syscall entries:
> > 
> >  struct async_syscall ringbuffer[1024];
> > 
> >  LIST_HEAD(submitted);
> >  LIST_HEAD(pending);
> >  LIST_HEAD(completed);
> 
> I strongly disagree here, and I'm hoping you're not as keen on this now --
> your reply to Matt gives me hope.
> 
> As mentioned, that they complete out-of-order leads, at least, to having
> separate submission and completion rings.  I'm not sure a submission ring
> makes any sense given the goal of processing the calls in submission and only
> creating threads if it blocks.  A simple copy of an array of these input
> structs sounds fine to me.

The "result" of one async operation is basically a cookie and a result 
code. Eight or sixteen bytes at most. IMO, before going wacko designing 
complex shared userspace-kernel result buffers, I think it'd be better 
measuring the worth-value of the thing ;)



- Davide