Re: [libvirt] [PATCH v3 0/4] Introduce new cputune event
On 09/15/2014 05:16 PM, Daniel P. Berrange wrote:
On Mon, Sep 15, 2014 at 05:12:12PM +0200, Pavel Hrdina wrote:
> This patch series introduce new cputune event to inform
> management applications about every change of cputune values
> for running domains.
>
> There is missing documentation for all events so the documentation
> for this event will be part of the patches to document all events.
Do you have any background on the motivation for this feature ?
This feature is request from oVirt and they would also like to have
event for blkdeviotune.
It would help to understand the use case better in order to decide
whether this is the right approach for the events. Specifically I
am wondering whether returning all the values in the event is the
best way. The alternative would be to have a generic "resource
tunable changed" event where we just specify the type of data that
changed, and allow the app to then fetch the new values if they
actually want them. This would let us deal with all the resource
tunables in a single event, isntead of having to add more events
for memory tunables, numa tunables, disk I/O, net I/O etc.
This event will return only the values that has been changed, not all
values that we have for cputune.
Having one "big" event for all tunables is a good idea and with the
typedParameters it should be easy. Let's say that the event would be
generic, then the typedParameter's field could be for cputune evetns:
"cpu.shares"
"cpu.emulatorpin"
"cpu.vcpu0"
or for example the blkiodevtune:
"blkdevio.total_bytes_sec"
etc...
Pavel
Regards,
Daniel