[zeromq-dev] Non-contiguous message thoughts

[Martin Sustrik]

Michael Santy wrote:
> 
>> At Fri, 05 Mar 2010 09:10:19 +0100, Martin Sustrik wrote:
>>
>> This is possible, if language runtime supports callbacks from foreign
>> thread (to call language code from C). However, handwritten memory
>> management wrapper kills performance. Unless you have to deal with
>> very large messages, it's usually faster just to copy data.
> 
> Thanks -- that definitely makes sense.  I agree that this would not be
> appropriate for small messages.  The messages that I'm considering creating
> are on the order of 200MB and are scattered across a handful of contiguous
> regions of memory.

In that case zero-copy makes sense IMO. As far as I understand the point 
where copying becomes problematic is when CPU cache size - which is 
couple of MB in most cases - is exceeded.

Martin