Re: Data transfer mechanisms
Lluís Vilanova <[email protected]>
| Newsgroups | gmane.comp.micro-kernel.l4.devel |
|---|---|
| Message-ID | <[email protected]> |
Adam Lackorzynski writes: > Hi, > On Sun Aug 11, 2013 at 20:10:29 +0300, Lluís Vilanova wrote: >> I'd like to compare the performance of two different synchronous data transfer >> mechanisms: >> >> * Copies >> * Page maps / unmaps >> >> For the second one, it looks like I can use the streammap example >> (pkg/examples/libs/l4re/streammap), although I'm lacking a mechanism to unmap >> the page before returning control to the client. > There's an unmap syscall: > l4_task_unmap(L4RE_THIS_TASK_CAP, l4_fpage(page_to_map, 12, L4_FPAGE_RWX), > L4_FP_OTHER_SPACES); >> It would also be nice to be >> able to pass the server a read-only region. > The server? Anyway, there are rights parameters. >> For the first one, I've only found the use of multiple send/recv operations >> through the limited amount of data available on the message registers. There is >> a "Gen_string" class in the "ipc_stream" header, which looks like it could >> support offline string transfers, but it's disabled at compile time and I could >> not find the actual code in fiasco that handles these transfers. > That's gone. The kernel only copies what's in the MRs. Thanks a lot for your help. In the end, I got the remapping working following the example in "examples/libs/l4re/c++/shared_ds". BTW, there's a file in the fiasco directory regarding benchmarking results. What kind of information is to be sent? Thanks, Lluis -- "And it's much the same thing with knowledge, for whenever you learn something new, the whole world becomes that much richer." -- The Princess of Pure Reason, as told by Norton Juster in The Phantom Tollbooth _______________________________________________ l4-hackers mailing list [email protected] http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers