Re: [Qemu-devel] [RFC 6/6] docs: Document QMP event rate limiting

[Eric Blake]

On 09/28/2015 02:38 AM, Markus Armbruster wrote:

>>> +++ b/docs/qmp/qmp-spec.txt
>>> @@ -175,6 +175,11 @@ The format of asynchronous events is:
>>>  For a listing of supported asynchronous events, please, refer to the
>>>  qmp-events.txt file.
>>>  
>>> +Some events are rate-limited to at most one per second.  If more
>>> +events arrive within one second, all but the last one are dropped, and
>>> +the last one is delayed.  Rate-limiting applies to each kind of event
>>> +separately.
>>
>> Do we also want to document that limits might be further tuned according
>> to other elements of the event, with VSERPORT_CHANGE "id" as the example?
> 
> You need to interpret "each kind of event" in a sufficiently fuzzy
> manner :)
> 
> Seriously, I'm open to suggestions for better language here.

Maybe:

Some events are rate-limited to at most one per second. If more events
of the same type (along with any other fields that an event documents as
being significant) arrive within one second, ...

or:

Some events are rate-limited to at most one per second, either for the
event type in general, or additionally considering other significant
fields as documented by a specific event.  If more equivalent events
arrive within one second, ...

But since you did point out that VSERPORT_CHANGE mentions the filtering
on "id", I guess I won't try too much harder to paint the bikeshed any
further.

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

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