Is there a lowlatency kernel available for Raspberry Pi3 running ubuntu

I had a few doubts :
1) Can we use the official Raspberry Pi source available at https://github.com/raspberrypi/linux to compile a kernel for Ubuntu as there are some device-specific patches already incorporated in this kernel repo ( officially handled by Pi foundation).

2) Is there a way we can use the upstream kernel on a raspberry pi running Ubuntu Mate.

3) Is there a low-latency kernel available for armhf architecture (for raspberry pi 3 and above).If not then how can we compile a low-latency kernel for armhf ( can we use the ubuntu downstream source with preempt_rt patch and compile it using the config file of the raspberry pi running ubuntu mate )? Can we compile the ubuntu kernel ( although it is a Linux kernel but has few ubuntu specific changes in the downstream so i am referring to it as a ubuntu kernel ) for the Raspberry Pi . If yes, then which configuration file of raspberry pi will we have to use to compile it successfully ( the official config file i.e. bcm2709_defconfig and similar ones already present in the official raspberry pi kernel source at https://github.com/raspberrypi/linux or is there some other way.