Re: [Qemu-devel] [PATCH 08/11] QMP: Asynchronous messages enable/disable support

[Anthony Liguori <anthony@codemonkey.ws>]

On 01/24/2010 08:17 AM, Avi Kivity wrote:
> On 01/24/2010 04:04 PM, Anthony Liguori wrote:
>>> I agree with that, but we can look at async messages as a baseline 
>>> protocol capability (thus no negotiation required), and the new 
>>> command only enabled individual messages.
>>
>>
>> To be honest, I don't think there's really a need to mask individual 
>> messages.  A client can always ignore messages it doesn't care 
>> about.  There is no side effect of receiving a message so there is no 
>> functional implication of receiving messages you don't care about.
>>
>> The only time it would matter is if we had a really high volume of 
>> messages.  I'd suggest waiting until a message is introduced that 
>> could potentially have a high rate and then implement a mechanism to 
>> mask it.  For now, it just adds unnecessary complexity.
>
> Fair enough.  But then, why can't all clients do that?  Dropping an 
> async notification is maybe one line of code.

I agree.  The only argument I can imagine for masking is if we had a 
really, really high volume event that caused bandwidth issues.  I don't 
think that's an appropriate use of async messages though so I don't 
think this will ever happen.

Regards,

Anthony Liguori