Re: [PATCH] KVM: Create debugfs statistics for each VM

[Janosch Frank <frankja@linux.vnet.ibm.com>]

On 02/04/2016 02:10 PM, Christian Borntraeger wrote:
> On 02/04/2016 02:05 PM, Paolo Bonzini wrote:
>>
>>
>> On 02/02/2016 15:14, Christian Borntraeger wrote:
>>> FWIW, the newly created subfolders,
>>>
>>> require QEMU commit 6590045e5dd2fb0b1d7cdc047ae0c52fd4bb5276
>>>     scripts/kvm/kvm_stat: Replaced os.listdir with os.walk
>>>
>>> Otherwise you might get errors like 
>>>
>>> Traceback (most recent call last):
>>>   File "scripts/kvm/kvm_stat", line 640, in <module>
>>>     curses.wrapper(tui, stats)
>>>   File "/usr/lib64/python2.7/curses/wrapper.py", line 43, in wrapper
>>>     return func(stdscr, *args, **kwds)
>>>   File "scripts/kvm/kvm_stat", line 547, in tui
>>>     refresh(sleeptime)
>>>   File "scripts/kvm/kvm_stat", line 523, in refresh
>>>     s = stats.get()
>>>   File "scripts/kvm/kvm_stat", line 483, in get
>>>     new = d.read()
>>>   File "scripts/kvm/kvm_stat", line 37, in read
>>>     return dict([(key, val(key)) for key in self._fields])
>>>   File "scripts/kvm/kvm_stat", line 36, in val
>>>     return int(file(self.base + '/' + key).read())
>>> IOError: [Errno 21] Is a directory: '/sys/kernel/debug/kvm/13123-31'
>>>
>>> when using the "-d" option.
>>>
>>>
>>> Paolo, I still think that this a valuable addon for debugging. Any guidance?
>>
>> Yeah, I agree...  Do we want to add a module parameter for this, and/or
>> a kernel configuration that for now defaults to N?
>>
> 
> 
>> An alternative is to move kvm_stat from QEMU to tools/.
> 
> Hmm, that is probably the best solution, given that it has no dependency
> on QEMU but heavily depends on the kernel module.

So, what's the plan then?

Give me some pointers and I'm happy to do the work, but I currently
don't have enough experience to know/guess what is wanted.

I still have about 3 or 4 patches for kvm_stat in my queue that will add
the filtering support for debugfs AND tracefs. One of them also adds
documentation to the script, as well as to the man page and I might add
one that brings py3 support.
Most of them are ready, but before finishing the filtering support I
wanted to wait until the kernel patch was in next.

Do you (Paolo) want to move this patch through kvm-next and the
corresponding python patches through qemu and later on move the script
to the kernel?

Cheers
Janosch