From 39fccd2fc33c95de8358451f58c52b9e4b828ddd Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Thu, 23 Mar 2017 14:13:25 +0800 Subject: [PATCH] stm class: Document the stm_ftrace 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 Signed-off-by: Alexander Shishkin --- 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 11cff47eecce..03765750104b 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