Re: [PATCH] stm class: Document the stm_ftrace

[Alexander Shishkin]

Hi Chunyan,

A couple of clarifications: iirc this applies to the function tracer
of ftrace, right? Does it make sense to mention that? Also, are you
planning to support other ftrace payloads like trace_printk()s?

Thanks,
--
Alex

On 20 March 2017 at 08:47, Chunyan Zhang <chunyan.zhang@xxxxxxxxxxxxxx> wrote:
> This patch adds a description of the stm_ftrace device source, an
> interface for collecting Function trace information via STM devices.
>
> Signed-off-by: Chunyan Zhang <chunyan.zhang@xxxxxxxxxxxxxx>
> ---
>  Documentation/trace/stm.txt | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/trace/stm.txt b/Documentation/trace/stm.txt
> index 11cff47..7ec1c0e 100644
> --- a/Documentation/trace/stm.txt
> +++ b/Documentation/trace/stm.txt
> @@ -83,7 +83,7 @@ by writing the name of the desired stm device there, for example:
>  $ echo dummy_stm.0 > /sys/class/stm_source/console/stm_source_link
>
>  For examples on how to use stm_source interface in the kernel, refer
> -to stm_console or stm_heartbeat drivers.
> +to stm_console, stm_heartbeat or stm_ftrace drivers.
>
>  Each stm_source device will need to assume a master and a range of
>  channels, depending on how many channels it requires. These are
> @@ -107,5 +107,13 @@ console in the STP stream, create a "console" policy entry (see the
>  beginning of this text on how to do that). When initialized, it will
>  consume one channel.
>
> +stm_ftrace
> +==========
> +
> +This is another "stm_source" device, once the stm_ftrace is linked with
> +an stm device, function address and parent function address which
> +Ftrace subsystem would store into ring buffer will be exported via the
> +stm device at the same time.
> +
>  [1] https://software.intel.com/sites/default/files/managed/d3/3c/intel-th-developer-manual.pdf
>  [2] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0444b/index.html
> --
> 2.7.4
>