Hi Josh,
thanks for your reply. I am aware of this feature for synchronous communications, which is really useful. But I have
to use asynchronous communications. Is there a possibility to do the same thing for asynch/notify? If not, I guess
the main thread of the cell has to multiplex messages to the other threads of the cell.
-H
On Wed, Oct 14, 2009 at 11:33 PM, Josh Matthews
<[hidden email]> wrote:
Hi Hannes,
What you're looking for are "Reply Capabilities". These are temporary (one-shot) capabilities that are created on receipt of a synchronous IPC - intended exactly for client-server type interactions such that the server does not need to possess a capability to every possible client (and can instead trust that as long as a client possesses a capability to the server, that client is valid and can be replied to).
Check out section B-18.4 of the OKL4 3.0 Library reference manual - you can see the reply_cap that you receive as an output parameter to okl4_message_wait.
Note that this is only for synchronous communications - you appear to be using asynch/notify. Is it possible for you to use synchronous comms?
Josh
On Fri, Oct 2, 2009 at 5:15 AM, Hannes Payer
<[hidden email]> wrote:
Well, this question seems to be somehow related to the question asked in
"Capability Passing in OKL4 3.0"
http://wiki.ok-labs.com/forum#nabble-td2241729. Can I dynamically create
these capabilities in the server cell at runtime? A client thread would have
to pass some information(?) to the server cell. The server would then have
to create the necessary capability and send the result back to the given
client thread. Is this possible in OKL4?
-H
Hannes Payer wrote:
>
> Hi,
>
> how can multiple threads running in one cell communicate with another
> cell? I looked at the available OKL4 documentation and played around with
> the API, but I am not sure how to get this done.
>
> The following program works for me:
> There are 2 cells running in the system. One is a server cell performing a
> calculation based on client input and returning the result to the client.
> The server cell waits for a notification (okl4_notify_wait) from the
> client cell. Whenever the client cell wants to communicate with the server
> it writes data to a known shared memory location and sends the server cell
> a notification (okl4_notify_send) and waits for a notification from the
> server for the result. The server cell looks-up the input in shared
> memory, computes the result, writes the result to shared memory and sends
> the client a notification. This example is very similar to the decrypt
> demo of the OKL4 examples and on a cell-to-cell communication basis this
> system works.
>
> My question:
> Can I implement this example also with multiple threads running in the
> client cell where each single thread communicates with the server cell?
> How does the server cell get the capability to send a given thread from
> the client cell a notification? Do I have to stick to cell-to-cell
> communication and multiplex the messages from the server cell on the
> client cell side?
>
> I hope my problem description is precise enough. Thank you very much for
> your help.
>
> -H
>
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