On Tue, 26 May 2020 21:46:29 +0000 Song Liu <songliubrav...@fb.com> wrote:
> > > > On May 26, 2020, at 2:39 PM, Peter Zijlstra <pet...@infradead.org> wrote: > > > > On Tue, May 26, 2020 at 02:28:26PM -0700, Song Liu wrote: > >> It is useful to trace functions in kernel/event/core.c. Allow ftrace for > >> them by removing $(CC_FLAGS_FTRACE) from Makefile. > > > > Did you try using the ftrace event with perf with this on? > > I have tried a few things, like > > perf stat -e probe:perf_read -I 1000 > perf record -e probe:__x64_sys_perf_event_open -aR > > They all work fine. Did you try using perf with function-tracer or function-graph tracer? If you just want to trace those functions with kprobes, you can build your kernel with CONFIG_KPROBE_EVENTS_ON_NOTRACE=y, which allows you to probe perf_read etc. Thank you, -- Masami Hiramatsu <mhira...@kernel.org>
