[cap-talk] Cap type safe OS questions

[Sam Mason]

On Sun, Aug 02, 2009 at 07:21:34PM +0100, Sam Mason wrote:
> On Mon, Aug 03, 2009 at 01:38:03AM +0800, Ben Kloosterman wrote:
> > I think this is mainly due to the high Context switch costs of the common
> > separate user address space , multiple privilege levels OS. The Singularity
> > paper " Singularity - Rethinking the Software Stack " shows good performance
> > with an Asych  IPC with an unoptomized kernel compared to L4.  
> 
> I was under the impression so far that you had two address spaces, one
> for the kernel and one for everything else.  The way you've been talking
> about the kernel fiddling with message queues would suggest that you
> have five address space switches per invocation:
> 
>   user -> kernel -> user -> kernel -> user

Sorry, that would be *four*.  Not sure what I was thinking there!

-- 
  Sam  http://samason.me.uk/