use ftrace during boot phase
use ftrace during boot phase
trace_buf_size [KMG]
比如trace_buf_size=1M,这将会把每个cpu的trace buffer设置为1M
trace_event
trace_event=sched:*,timer:*,irq:*
trace_options
用逗号隔开的option list,比如trace_options=stacktrace(trace里的结果将包含stacktrace)
trace option有如下这些:
/sys/kernel/debug/tracing # cat trace_options print-parent nosym-offset nosym-addr noverbose noraw nohex nobin noblock trace_printk annotate nouserstacktrace nosym-userobj noprintk-msg-only context-info nolatency-format record-cmd norecord-tgid overwrite nodisable_on_free irq-info markers noevent-fork stacktrace notest_nop_accept notest_nop_refuse
ftrace
比如ftrace=function_graph,tracer设置为function_graph,开机过程中会自动开启tracing,tracing_on的值将为1。如果没有设置ftrace cmdline arg,尽管你有设置trace event,开机过程中不会自动enable trace(tracing_on的值还是0)
reference: https://cloud.tencent.com/developer/article/1797239