一、配置打开Ftrace功能
打开ftrace的配置宏
diff --git a/arch/arm64/configs/j5_dvb_bringup_defconfig b/arch/arm64/configs/j5_dvb_bringup_defconfig
index 5928570672f6..675469ed8079 100644
--- a/arch/arm64/configs/j5_dvb_bringup_defconfig
+++ b/arch/arm64/configs/j5_dvb_bringup_defconfig
@@ -558,3 +558,8 @@ CONFIG_MEMTEST=y
# CONFIG_ARCH_RANDOM is not set
# CONFIG_ARM64_AS_HAS_MTE is not set
# CONFIG_ARM64_MTE is not set
+CONFIG_FTRACE=y
+CONFIG_FUNCTION_TRACER=y
+CONFIG_FUNCTION_GRAPH_TRACER=y
+CONFIG_STACK_TRACER=y
+CONFIG_DYNAMIC_FTRACE=y二、Tracing文件系统介绍
内容来自：https://www.kernel.org/doc/Documentation/trace/ftrace.txt
current_tracer，设置和查看当前的tracer。
available_tracers，查看所支持的tracer。
tracing_on，开关trace。
trace，cat trace的信息。
trace_pipe，
trace_options，
options
annotate
set_ftrace_filter，查看和设置要跟踪的函数。
set_ftrace_notrace，查看和设置不跟踪的函数。
set_ftrace_pid，查看和设置需要跟踪的pid。
set_event_pid，
二、使用示例
只查看hobot_mipihost函数的调用情况
命令：
root@j5dvb:/sys/kernel/debug/tracing# echo 0 > tracing_on
root@j5dvb:/sys/kernel/debug/tracing# cat available_tracers
function_graph function nop
root@j5dvb:/sys/kernel/debug/tracing# echo function_graph > current_tracer
root@j5dvb:/sys/kernel/debug/tracing# cat current_tracer
function_graph
root@j5dvb:/sys/kernel/debug/tracing# echo ":mod:hobot_mipihost" > set_ftrace_filter
root@j5dvb:/sys/kernel/debug/tracing# echo > trace
root@j5dvb:/sys/kernel/debug/tracing# echo 1 > tracing_on
root@j5dvb:/sys/kernel/debug/tracing#
root@j5dvb:/sys/kernel/debug/tracing# cat traceecho ":mod:hobot_mipihost" > set_ftrace_filter只跟踪hobot_mipihost module的函数echo "*open*:mod:hobot_mipihost" > set_ftrace_filter只跟踪hobot_mipihost module的*open*函数echo "!*open*:mod:hobot_mipihost" >> set_ftrace_filter删除对hobot_mipihost module*open*函数的跟踪echo "!*:mod:hobot_mipihost" >> set_ftrace_filter禁止对hobot_mipihost module之外的函数跟踪echo "!*:mod:*" >> set_ftrace_filter禁用所有模块的跟踪，但仍跟踪内核：
演示：
.png)
跟踪mipihost和cim_dma的调用情况
命令：
root@j5dvb:/sys/kernel/debug/tracing# echo 0 > tracing_on
root@j5dvb:/sys/kernel/debug/tracing# cat available_tracers
function_graph function nop
root@j5dvb:/sys/kernel/debug/tracing# echo function_graph > current_tracer
root@j5dvb:/sys/kernel/debug/tracing# cat current_tracer
function_graph
root@j5dvb:/sys/kernel/debug/tracing# echo ":mod:hobot_mipihost" > set_ftrace_filter
root@j5dvb:/sys/kernel/debug/tracing# echo ":mod:hobot_cim_dma" >> set_ftrace_filter
root@j5dvb:/sys/kernel/debug/tracing# echo > trace
root@j5dvb:/sys/kernel/debug/tracing# echo 1 > tracing_on
root@j5dvb:/sys/kernel/debug/tracing#
root@j5dvb:/sys/kernel/debug/tracing# cat traceecho ":mod:hobot_mipihost" > set_ftrace_filter设置hobot_mipihost module跟踪echo ":mod:hobot_cim_dma" >> set_ftrace_filter追加设置hobot_cim_dma module跟踪
演示：
.png)
Ftrace vps
trace/app/bin/vps/vpm/vio_test_case.sh cicd_sen_cimdma_ddr_isp0_pym0_4k_ar0820程序对vps相关模块函数的调用关系。
echo 0 > tracing_on
cat available_tracers
function_graph function nop
echo function_graph > current_tracer
cat current_tracer
function_graph
echo 102400 > buffer_size_kb
echo ":mod:hobot_mipihost" > set_ftrace_filter
echo ":mod:hobot_mipidev" >> set_ftrace_filter
echo ":mod:hobot_mipidphy" >> set_ftrace_filter
echo ":mod:hobot_cim_dma" >> set_ftrace_filter
echo ":mod:hobot_cim" >> set_ftrace_filter
echo ":mod:hobot_videostitch" >> set_ftrace_filter
echo ":mod:hobot_gdc" >> set_ftrace_filter
echo ":mod:hobot_pym_jplus" >> set_ftrace_filter
echo ":mod:hobot_sensor" >> set_ftrace_filter
echo ":mod:hobot_camsys" >> set_ftrace_filter
echo ":mod:hobot_vio_common" >> set_ftrace_filter
echo > trace
echo 1 > tracing_on
/app/bin/vps/vpm/vio_test_case.sh cicd_sen_cimdma_ddr_isp0_pym0_4k_ar0820
cat trace > /userdata/trace.txt三、trace文件分析工具
Google trace viewer
Google perfetto
