Re: wortel syscall wrappers

[Marcus Brinkmann]

On Tue, Jan 20, 2004 at 03:37:12PM +0100, Niels M?ller wrote:
> > Is there really a need for this type of sanity tests?  First the 
> > message must pass the wortel control cap test.  And if it passes
> > that, and the message is still not correct, then something is 
> > really wrong, and the system deserve to crash and burn.
> 
> Well, I think it's good style to not move the responsibility for
> protocol syntax and safety from the server onto the client.

We are not talking about a client-server protocol here, but about a kernel
interface, which as the primary design concern has performance.  Secondary
concern is performance.  Third one is performance, too.  There are no other
concerns ;) except compatibility, maybe.


We might want to have one thread per CPU here, to avoid X-CPU IPC.  We will
also likely want to either write or let the IDL compiler write special
optimized versions for these.

However, in the abstract sense, the wrappers should be as lean as possible. 
No argument checks, etc, just plain pass-through.

> [1] Perhaps we'll pay a few cycles if the switch on label alone is
>     compiled to a jump table, and the above construction is not. But
>     it's much too early to worry about that ;-) Hopefully we'll use
>     some tools too automatically generate good code for this dispatch.

We'll need IDL compilers.  If we can/should use them for the stubs I am not
sure, nor is it a primary concern.  The number of such stubs is small and
they don't change frequently.

Thanks,
Marcus

-- 
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Marcus Brinkmann              The Hurd http://www.gnu.org/software/hurd/
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