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

[Eric Blake]

On 2/13/20 9:27 PM, Keqian Zhu 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.
>
> This doesn't conflict with cpu_throttle_increment.
>
> This may make migration time longer, and is disabled
> by default.
>
> Signed-off-by: Keqian Zhu <address@hidden>
> ---
> Cc: Juan Quintela <address@hidden>
> Cc: "Dr. David Alan Gilbert" <address@hidden>
> Cc: Eric Blake <address@hidden>
> Cc: Markus Armbruster <address@hidden>

> +++ b/qapi/migration.json
> @@ -532,6 +532,12 @@
>   #                          auto-converge detects that migration is not making
>   #                          progress. The default value is 10. (Since 2.7)
>   #
> +# @cpu-throttle-tailslow: Make throttle slower at tail stage
> +#                         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. The default
> +#                         value is false. (Since 4.1)

The next release is 5.0, not 4.1.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org