Messages in this thread | | | Date | Mon, 30 Nov 2009 10:11:52 -0500 | From | Steven Rostedt <> | Subject | Re: ftrace not showing stack trace data during boot processes |
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Note, please Cc maintainers directly if you want a response. This mailing list has a traffic of 600 emails a day, and things sent here can easily be lost.
On Sun, Nov 29, 2009 at 06:20:35PM -0800, Subodh Nijsure wrote: > I am trying to debug some boot sequences during kernel bootup and > trying to use ftrace to discover function flow. > > I am booting kernel with following options. > > stacktrace trace_buf_size=30M ftrace=function
Note, the stacktrace is the stack tracer, not the tracing option of "stacktrace" or the function trace option "func_stack_trace".
The output of the stack tracer just shows the max stack trace and is listed in
debugfs/tracing/stack_trace
> ftrace_filter=do_sync_write,usbfs*,ext2_*,vfs_write,blkdev_*,vfs_write,sys_write > ftrace_notrace=ext2_permission > > I have compiled kernel with following options > > CONFIG_NOP_TRACER=y > CONFIG_HAVE_FUNCTION_TRACER=y > CONFIG_HAVE_DYNAMIC_FTRACE=y > CONFIG_HAVE_FTRACE_MCOUNT_RECORD=y > CONFIG_RING_BUFFER=y > CONFIG_TRACING=y > CONFIG_FUNCTION_TRACER=y > CONFIG_SYSPROF_TRACER=y > CONFIG_CONTEXT_SWITCH_TRACER=y > CONFIG_BOOT_TRACER=y > CONFIG_STACK_TRACER=y > CONFIG_DYNAMIC_FTRACE=y > CONFIG_FTRACE_MCOUNT_RECORD=y > > However when I look at /sys/kernel/debug/tracing/trace > > I see output similar to this and I don't see the "stack trace" > init-1 [000] 65.317499: sys_write <-sysenter_do_call > init-1 [000] 65.317504: vfs_write <-sys_write > init-1 [000] 65.317617: sys_write <-sysenter_do_call > init-1 [000] 65.317619: vfs_write <-sys_write > > Is there option I am missing while compiling kernel or some part of > kernel parameters is missing? Is there way to explicitly specify > iter_ctrl on kernel boot cmdline?
Currently there is no way to enable an option from the kernel command line. I could write something up though.
-- Steve
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