Re: [PATCH] block: BFQ default for single queue devices

Bart Van Assche
2018-10-04T20:09:06Z

On Thu, 2018-10-04 at 20:25 +0100, Alan Cox wrote:
> > I agree with Jens that it's best to leave it to the Linux distributors to
> > select a default I/O scheduler.
>
> That assumes such a thing exists. The kernel knows what devices it is
> dealing with. The kernel 'default' ought to be 'whatever is usually best
> for this device'. A distro cannot just pick a correct single default
> because NVME and USB sticks are both normal and rather different in needs.

Which I/O scheduler works best also depends which workload the user will run.
BFQ has significant advantages for interactive workloads like video replay
with concurrent background I/O but probably slows down kernel builds. That's
why I'm not sure whether the kernel should select the default I/O scheduler.

Bart.