Re: [PATCH 0/5] BT scheduling class

[Peter Zijlstra]

On Fri, Jun 21, 2019 at 03:45:52PM +0800, xiaoggchen@xxxxxxxxxxx wrote:
> From: chen xiaoguang <xiaoggchen@xxxxxxxxxxx>
> 
> This patch set introduces a new scheduler, we name it BT scheduler
> for the moment.

> The BT scheduler is similar with the CFS scheduler. We also use the
> rb-tree as the run queue to save the runnable tasks. And the vruntime 
> concept is also used in the BT scheduler. And the priority of BT scheduler
> is from 140 to 179. So now the schedulers in the kernel are as follows:
> deadline, RT, CFS, BT and idle.

NAK; it has no forward progress guarantees. This is also the reason why
SCHED_IDLE is not a true idle time scheduler but a very low weight CFS
tasks.

It also has some very 'interesting' starvation cases, consider one of
your BT tasks owns a mutex, but then there are there are runnable CFS
tasks. The BT task will never get runtime and release the mutex.

Also; NAK at all the duplication.