Re: [Qemu-devel] [PATCH 07/10] monitor: Expose pvrdma device statistics counters

[Eric Blake]

On 1/31/19 2:08 PM, Yuval Shaia wrote:
> On Thu, Jan 31, 2019 at 07:17:16AM -0600, Eric Blake wrote:
>> On 1/31/19 7:08 AM, Yuval Shaia wrote:
>>> Signed-off-by: Yuval Shaia <address@hidden>
>>> ---
>>>  hmp-commands-info.hx | 14 ++++++++++++++
>>>  monitor.c            |  6 ++++++
>>>  2 files changed, 20 insertions(+)
> 
> Hi Eric,
> 
>>
>> Commit message should state WHY this is being added as an HMP-only
>> command, and does not have a QMP counterpart.  It may be okay if the
>> interface is only designed to be useful to developers, but having that
>> justification in the git log is important.
> 
> Thanks for your review.
> 
> See, i need this interface mainly for development/debug purposes, to help
> troubleshot problems and to give insights to what device "is doing".
> 
> Trace points are great but not effective in high load.
> QMP as i see it, and correct me if i'm wrong, is used to report management
> events etc and also here, is not effective in high load.
> 
> I choose this interface as it is interactive, i.e. whenever i need the info
> i trigger 'info pvrdmastats' command from the monitor console.
> 
> During my research i notice that some devices (or families) have nice user
> interface via virsh (blkstat, ifstat, memstat etc). Is it the preferred way
> for non-devel/debug purposes?

Using existing HMP-only debug interfaces as the design you copied is
indeed acceptable justification for making yours HMP-only as well.  So
now you just need to copy the rationale from this email into your commit
message, so it doesn't get lost.

> 
> If this is the correct method for this purpose then let me know and i'll
> update the git log message accordingly.
> 


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

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