linux-kernel - Re: When and how to use ftrace?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 9 Jun 2010 16:59:03 +0800
From:	wu zhangjin <wuzhangjin@...il.com>
To:	Ryan Wang <openspace.wang@...il.com>
Cc:	Neependra Khare <neependra.khare@...il.com>,
	Steven Rostedt <srostedt@...hat.com>,
	linux-kernel@...r.kernel.org, kernelnewbies@...linux.org
Subject: Re: When and how to use ftrace?

Hi,

On Wed, Jun 9, 2010 at 4:14 PM, Ryan Wang <openspace.wang@...il.com> wrote:
[...]
>>>
>>> --
>>> To unsubscribe from this list: send an email with
>>> "unsubscribe kernelnewbies" to ecartis@...linux.org
>>> Please read the FAQ at http://kernelnewbies.org/FAQ
>>>
>>
>>
>
> 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@...il.com         http://falcon.oss.lzu.edu.cn
Address:Tianshui South Road 222,Lanzhou,P.R.China    Zip Code:730000
Tel:+86-931-8912025
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/