Re: When and how to use ftrace?

[Ryan Wang]

2010/6/9 wu zhangjin <wuzhangjin@xxxxxxxxx>:
> Hi,
>
> On Wed, Jun 9, 2010 at 4:14 PM, Ryan Wang <openspace.wang@xxxxxxxxx> wrote:
> [...]
>>>>
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>>
>> Seems ftrace is helpful to study the activities inside the kernel to me.
>> I wonder whether it can be useful to debug kernel bugs. And if so, will
>> you please give me some examples?
>
> Yeah, did you read this paper written by Steven: "Finding Origins of
> Latencies Using Ftrace" (please google to download it).
> If not, please read it. that paper will tell you what Ftrace really is
> and will show the demos how to play with it.
>
>> Or so far it's mainly used for
>> observing the running status of kernel?
>
> Ftrace is originally created for debugging and optimizing the
> preempt-rt, but of course, it becomes a tracing framework currently.
>
> It not only show you what the kernel space does when you do something
> in user space,
> but will show you the calling tree of kernel functions, time consuming
> of  every function and
> even allow you to filter the parts you care about.
>
> If you need more info about it, please refer to:
>
> [1] Debugging the kernel using Ftrace
> http://lwn.net/Articles/365835/
> http://lwn.net/Articles/366796/
> [2] Ftrace usage ....
> Documentation/trace/ftrace.txt
> Documentation/trace/ftrace-desgin.txt
> [3] Tools for Ftrace
> trace-cmd from readhat...
>
> Regards,
>
> --
> Studying engineer. Wu Zhangjin
> Lanzhou University      http://www.lzu.edu.cn
> Distributed & Embedded System Lab      http://dslab.lzu.edu.cn
> School of Information Science and Engeneering         http://xxxy.lzu.edu.cn
> wuzhangjin@xxxxxxxxx         http://falcon.oss.lzu.edu.cn
> Address:Tianshui South Road 222,Lanzhou,P.R.China    Zip Code:730000
> Tel:+86-931-8912025
>

Thanks all!
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