Copy small payloads - less header more efficiency

[jeising]

Brief feature description

Currently there is no copy in iceoryx communication. To enable this, there is a header to every message send around. This header has a considerable size.

The proposal would be to - like for functions, where you can copy the parameters or call them by reference/pointer - enable the possibility of copying small payloads (maybe half the size of the header) to foster the incentive to use iceoryx also for small messages.

This way the user does not need to consider, whether it would be smarter to copy or to use shared memory.

Detailed information

Cons:

• It is work to implement this
• There needs to be a way to make this somewhat transparent
• All tools and interfaces need to work with this

Pros:

• Broader field of usage
• Better memory efficiency for smaller payloads
• No need to work around this communication channel

[budrus]

@jeising I currently see no other way than introducing another IPC mechanism like UDS or message queue. In fact we already use them for the communication with the RouDi daemon. From what I saw, iceoryx was still faster than those built-in OS IPC mechanisms also for messages with a size of some bytes. An optimization for intra-process could make sense. What was your problem? Or did you just think it could be more memory efficient?