Re: [PATCH] migration/throttle: Make throttle slower at tail stage

[Juan Quintela]

Keqian Zhu <address@hidden> wrote:
> At the tail stage of throttle, VM is very sensitive to
> CPU percentage. We just throttle 30% of remaining CPU
> when throttle is more than 80 percentage.

Why?

If we really think that this is better that current approarch, just do
this _always_.  And throothre 30% of remaining CPU.  So we go:

30%
30% + 0.3(70%)
...

Or anything else.

My experience is:
- you really need to go to very high throothle to make migration happens
  (more than 70% or so usually).
- The way that we throotle is not completely exact.

> This doesn't conflict with cpu_throttle_increment.
>
> This may make migration time longer, and is disabled
> by default.


What do you think?
I think that it is better to change method and improve documentation
that yet adding another parameter.

Later, Juan.