Re: Efficient IPC mechanism on Linux

[Chris Friesen]

Martin Konold wrote:
> Am Wednesday 10 September 2003 08:01 pm schrieb Andrea Arcangeli:

> > with the shm/futex approch you can also have a ring buffer to handle
> > parallelism better while it's at the same time zerocopy
>
> How fast will you get? I think you will get the bandwidth of a memcpy for 
> large chunks?!
>
> This is imho not really zerocopy. The data has to travel over the memory bus 
> involving the CPU so I would call this single copy ;-)

Even with zerocopy, you have to build the message somehow.  If process A 
builds a message and passes it to process B, then then isn't that as 
efficient as you can get with message passing?  How does MPI do any better?

However, if both processes directly map the same memory and use it 
directly (without "messages" as such), then I would see *that* as zerocopy.

Chris

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