Messages in this thread | | | Date | Wed, 27 May 2020 14:40:40 +0900 | From | Masami Hiramatsu <> | Subject | Re: [RFC] perf/core: allow ftrace for functions in kernel/event/core.c |
| |
On Tue, 26 May 2020 21:46:29 +0000 Song Liu <songliubraving@fb.com> wrote:
> > > > On May 26, 2020, at 2:39 PM, Peter Zijlstra <peterz@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 <mhiramat@kernel.org>
| |