how to measure IRQ service latency

[miloody@gmail.com (loody)]

hi :
thanks for your help :)

2011/1/13 loody <miloody@gmail.com>:
> Hi
>
> 2011/1/13 neependra.khare at gmail.com <neependra.khare@gmail.com>:
>>
>>
>> On Thu, Jan 13, 2011 at 10:23 AM, loody <miloody@gmail.com> wrote:
>>>
>>> hi:
>>>
>>> 2010/12/22 neependra.khare at gmail.com <neependra.khare@gmail.com>:
>>> >
>>> >
>>> > On Wed, Dec 22, 2010 at 5:30 PM, Pradeep Kumar <pradeepkernel@gmail.com>
>>> > wrote:
>>> >>
>>> >> hi,
>>> >> ?? ?can any one suggest a way to measure IRQ service latency? .
>>> >
>>> > I believe you can measure it with Ftrace. You might need to use irqsoff
>>> > tracer.
>>> > For reference:-
>>> > http://people.redhat.com/srostedt/
>>> I go into the website and see a lot of files with suffix odp.
>>
>>
>> These are presentations which you can open with Open Office.
>> Those contain the examples as well.
>>
>>>
>>> is there any document which can tell us how to use it?
>>
>> http://lwn.net/Articles/365835/
>> http://lwn.net/Articles/366796/
>> http://lwn.net/Articles/370423/
>>
>> You can look at my presentation which I gave at FOSS.in?and see it is
>> useful.
>> http://neependra.net/?p=148
I have some questions about the document you mention:
1. I tried lttv recently and it seems different than the ftrace.
Is there any document or setting can help me to tell them apart?

2. there is a column called "TRACE" in kernel menuconfig, is it used
for ftrace or lttv?
appreciate your help,
miloody