Re: [Qemu-devel] [PATCH v4 2/6] add basic backup support to block driver

[Dietmar Maurer]

> I just reread the code and noticed the delay is 1 microsecond, not 1 
> millisecond.

Yes, It does not really add a delay.

> The problem is that this is a magic value.  It worked on your machine with 
> your
> workload, but there's no guarantee it works on anyone else's machine or
> workload.  We can't depend on magic values like this.
> 
> If you want to implement an alternative to rate-limiting, please do it in a
> separate patch series and make it work for all block job types.

Well, I hoped you can see how to fix that. I guess the same applies for other 
types of block
jobs, and I simply found no other solution.

Adding and IO queue and implement a scheduler is likely not what we want to do.