Re: [Qemu-devel] [PATCH v2 3/3] qmp/hmp: Add throttle ratio to query-migrate and info migrate

[Eric Blake]

On 06/02/2015 11:46 AM, Jason J. Herne wrote:
> Report throttle ratio in info migrate and query-migrate responses when cpu
> throttling is active.
> 
> Signed-off-by: Jason J. Herne <address@hidden>
> ---
>  hmp.c                 | 5 +++++
>  migration/migration.c | 5 +++++
>  qapi-schema.json      | 3 ++-
>  3 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/hmp.c b/hmp.c
> index e17852d..cb3c137 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -229,6 +229,11 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
>                         info->xbzrle_cache->overflow);
>      }
>  
> +    if (info->has_x_cpu_throttle_ratio) {
> +        monitor_printf(mon, "cpu throttle ratio : %0.2f\n",

s/ :/:/

How big or small can the ratio get? Is %g going to be nicer than %f if
the ratio goes through a large range of possibilities?

> +++ b/qapi-schema.json
> @@ -483,7 +483,8 @@
>             '*total-time': 'int',
>             '*expected-downtime': 'int',
>             '*downtime': 'int',
> -           '*setup-time': 'int'} }
> +           '*setup-time': 'int',
> +           '*x-cpu-throttle-ratio': 'number'} }

Even though it is marked experimental, it is still worth documenting
this parameter, and include mention of how to interpret it (0.0 means no
throttling, 1.0 means 50% duty cycle, 2.0 means 33% duty cycle, right?).
Documentation should mention '(since 2.4)'

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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