Re: [Xen-devel] Re: [PATCH] add long interrupt measurement capability

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

I applied it earlier today.


On 18/05/2009 21:41, "Dulloor" <dulloor@xxxxxxxxx> wrote:

> Hi Keir,
> 
> Can you consider this for check-in.
> 
> -dulloor
> 
> 2009/5/11 Dulloor <dulloor@xxxxxxxxx>
>> - Changed the name to trace_irq :)
>> 
>> - trace_irq dumps just tsc_in and tsc_out values in a single record. I guess
>> there is no need to write two records (wasting trace-buf mem, more
>> processing, additional logic in xentrace and/or xentrace_format).
>> 
>> - xentrace_format does what Dan wanted.
>> 
>> -dulloor
>> 
>> 2009/5/11 Tian, Kevin <kevin.tian@xxxxxxxxx>
>> 
>>> I guess you can handle it much simpler by stamping a record in both
>>> irq_enter and irq_exit. All the statistics jobs are left for xentrace script
>>> to digest.
>>>  
>>> Also I'd call it as trace_irq instead of trace_guest_irq. :-)
>>>  
>>> Thanks,
>>> Kevin
>>> 
>>>>  
>>>>  
>>>> 
>>>>  From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>>> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of  Dulloor
>>>> Sent: 2009年5月9日 17:12
>>>> To: Keir  Fraser
>>>> Cc: Ian Pratt; Xen-Devel (E-mail); Dan  Magenheimer
>>>> 
>>>> Subject: Re: [Xen-devel] Re: [PATCH] add long interrupt  measurement
>>>> capability
>>>> 
>>>>  
>>>> Here is a xentrace patch.
>>>> 
>>>> - Should irq_desc_measure_t move  to some .h file ?
>>>> - I have defined the new trace event in general class. Is  it fine ?
>>>> 
>>>> - I have defined tsc_in as volatile to avoid initializing it  in the main
>>>> code path.
>>>> 
>>>> thanks
>>>> dulloor
>>>> 
>>>>  
>>>> On Sat, May 9, 2009 at 3:56 AM, Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
>>>> wrote:
>>>>  
>>>>>  
>>>>> On 08/05/2009 22:53, "Ian Pratt" <Ian.Pratt@xxxxxxxxxxxxx> wrote:
>>>>> 
>>>>>>>  Perhaps.  However measuring cycles is important and, more
>>>>>>>  specifically, measuring MAX cycles spent across a set of
>>>>>>>  interrupts.  As a result, I suspect any code that measures
>>>>>>>  this (regardless of whether the result is reported by
>>>>>>> xentrace  or debug-key) would likely encounter the
>>>>>>> same objection from  Keir.
>>>>>> 
>>>>>> I can't imagine there'd be any objection to adding  trace macros to
>>>>>> record
>>>>>> this. The xentrace log processing tool can  then be updated to generate
>>>>>> max or
>>>>>> histogram  values.
>>>>> 
>>>>> Yes, xentrace records would be okay. It's adding  another debug key and
>>>>> printing to Xen console for this purpose which I do  not think is
>>>>> worthwhile.
>>>>> 
>>>>>  --  Keir
>>>>> 
>>>>> 
>>>> 
>> 
> 
> 



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