Driver with hard RT requiremnets

[Greg KH]

On Mon, Dec 05, 2016 at 04:24:05PM +0200, Ran Shalit wrote:
> Hello,
> 
> We need to support serial driver with real time requirements (towards specific
> device with RT demands):
> Every 5.3msec receive 100 bytes and 1.3msec afterwards send 100 bytes.
> 
> 1. Does kernel support real-time of such hard requirements ?

It depends on the hardware you are using, does your hardware provide
enough processing power and lack of harware interruptions (i.e. SMI) to
allow this to work properly?

> 2. Is it matter if we do the exact bytes send/receive from kernel or userspace,
> i.e. is kernel more real-time than userspace ?

It depends on your userspace code, people write real-time Java code in
userspace just fine.

> 3. Is mainline kernel unable to support such requirements and we better use RT
> patch such as xemonai ?

Why not try it out yourself and see?  You have the code and the hardware
to test, you don't need us to tell you if this works or not :)

good luck!

greg k-h