Re: [PATCH v2] stm class: Document the stm_ftrace

From: Chunyan Zhang
Date: Thu Apr 27 2017 - 01:33:54 EST


Hi Alex,

Could you take this patch please if there's no further comments?

Thanks,
Chunyan

On 23 March 2017 at 14:13, Chunyan Zhang <chunyan.zhang@xxxxxxxxxxxxxx> wrote:
> This patch adds a description to the stm_ftrace device source, an
> interface for collecting Ftrace's function trace information via
> STM devices.
>
> Signed-off-by: Chunyan Zhang <chunyan.zhang@xxxxxxxxxxxxxx>
> ---
> Documentation/trace/stm.txt | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/trace/stm.txt b/Documentation/trace/stm.txt
> index 11cff47..0376575 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 +107,16 @@ 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 has been
> +linked with an stm device, and if "function" tracer is enabled,
> +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.
> +
> +Currently only Ftrace "function" tracer is supported.
> +
> [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
>