Boot-time Tracing support

modulename: trace_boot.ko

configname: CONFIG_BOOTTIME_TRACING

Linux Kernel Configuration
└─>Kernel hacking
└─>Tracers
└─>Boot-time Tracing support
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Enable developer to setup ftrace subsystem via supplemental
kernel cmdline at boot time for debugging (tracing) driver
initialization and boot process.

source code:
kernel/trace/trace_boot.c
selects
CONFIG_BOOT_CONFIG