Re: Enabling ftrace on ARM MMU-less system

From: Steven Rostedt
Date: Tue Sep 30 2014 - 09:03:44 EST


On Tue, 30 Sep 2014 16:26:49 +0530
Amit Virdi <amitvi128@xxxxxxxxx> wrote:

> Hi,
>
> I'm trying to enable Ftrace on my ARM based MMU-less system.
> Unexpectedly, I don't see tracing directory under /sys/kernel/debug
> I have done the following so far but no success:
> 1. Verified that I have enabled these flags in my .config
> CONFIG_FUNCTION_TRACER
> CONFIG_FUNCTION_GRAPH_TRACER
> CONFIG_STACK_TRACER
> CONFIG_DYNAMIC_FTRACE
>
> 2. Enabled Ftrace startup steps. The startup log output is
> ----
>

> Can anyone help what I'm missing or if ftrace is supported on MMU-less
> platforms?

Well it's obviously supported if you see the tests running.

Is there anything else under /sys/kernel/debug? If not you need to
mount the debugfs filesytem there. It wont do it itself.

# mount -t debugfs nodev /sys/kernel/debug

-- Steve
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