Yet another question. Associated with "Re: Shared library"

[Christian Helmuth]

Hi Peter,

On Sun, Mar 07, 2010 at 01:02:55PM +1030, Peter Nguyen wrote:
> This makes sense. In reference to my responses above, I'm thinking there would
> be a profiling session interface that defines the memory that can be shared,
> have the server write data to this memory, and the clients can declare a
> dataspace capability (via attaching the dataspace as you mentioned) to this
> memory so as to read the contents of this memory. Am I on the right track?

Sounds good, though I expected the clients to write sampling data into
the memory that is processed by the profiling server. More precisely,
the server allocates the shared dataspace from its RAM session and
provides the associated RAM-dataspace capability to its clients. Both
- client and server - attach the dataspace to their virtual memory
and, thereafter, share access to the same RAM pages.

Regarding the mentioned "static variables" in Java... these only work
for sharing data within one Java VM. A multi-tasking system like our
microkernel-based multi-server OS is more like running an VM per
process. Any process then has to explicitly share data via external
(non-language) mechanisms (e.g., files or sockets).

Regards
-- 
Christian Helmuth
Genode Labs

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