Probe point 'bch_journal' not found. Error: Failed to add events.

[root@kevin ~]# perf probe bch_journal
Probe point 'bch_journal' not found.
  Error: Failed to add events.

[root@kevin ~]# perf probe -m /lib/modules/3.10.0-514.16.1.el7.4.x86_64/kernel/drivers/md/bcache/bcache.ko -a bch_journal

Added new event:

  probe:bch_journal    (on bch_journal in bcache)

You can now use it in all perf tools, such as:

        perf record -e probe:bch_journal -aR sleep 1

ref: http://oliveryang.net/2016/07/linux-perf-tools-tips/#311-perf-cannot-find-external-module-symbols

ftrace / trace-cmd usage, perf

trace-cmd record -p function -l generic_make_request --func-stack
trace-cmd report |less

trace-cmd record -p function -l submit_bio

trace-cmd record -p function_graph -g submit_bio

perf probe -a