Re: [PATCH] migration/throttle: Add throttle-trig-thres migration parameter

[Eric Blake]

On 2/20/20 8:57 PM, Keqian Zhu wrote:
> Currently, if the bytes_dirty_period is more than the 50% of
> bytes_xfer_period, we start or increase throttling.
>
> If we make this percentage higher, then we can tolerate higher
> dirty rate during migration, which means less impact on guest.
> The side effect of higher percentage is longer migration time.
>
> We can configure this parameter to switch between migration time
> firt or guest performance first. The default value is 50.
>
> 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
> @@ -524,6 +524,10 @@
>   #                      compression, so set the decompress-threads to the 
> number about 1/4
>   #                      of compress-threads is adequate.
>   #
> +# @throttle-trig-thres: The ratio of bytes_dirty_period and bytes_xfer_period 
> to
> +#                       trigger throttling. It is expressed as percentage. The
> +#                       default value is 50. (Since 5.0)
> +#

Abbreviating feels odd; can you please spell this out as 
throttle-trigger-threshold?

Can the threshold exceed 100%?

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