From: Masami Hiramatsu <mhiramat@kernel.org>
To: Song Liu <songliubraving@fb.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Kernel Team <Kernel-team@fb.com>, Ingo Molnar <mingo@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"Jiri Olsa" <jolsa@redhat.com>,
Namhyung Kim <namhyung@kernel.org>,
Alexey Budankov <alexey.budankov@linux.intel.com>
Subject: Re: [RFC] perf/core: allow ftrace for functions in kernel/event/core.c
Date: Wed, 27 May 2020 14:40:40 +0900 [thread overview]
Message-ID: <20200527144040.3f12026f31b20b2011fbbcee@kernel.org> (raw)
In-Reply-To: <A9B20D93-748B-4789-801E-91720E2D4F28@fb.com>
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>
next prev parent reply other threads:[~2020-05-27 5:40 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200526212826.4097888-1-songliubraving@fb.com>
2020-05-26 21:39 ` [RFC] perf/core: allow ftrace for functions in kernel/event/core.c Peter Zijlstra
2020-05-26 21:46 ` Song Liu
2020-05-26 21:54 ` Peter Zijlstra
2020-05-26 22:04 ` Steven Rostedt
2020-05-26 22:05 ` Steven Rostedt
2020-05-26 22:09 ` Song Liu
2020-06-05 21:58 ` Song Liu
2020-06-05 22:02 ` Steven Rostedt
2020-06-15 18:27 ` Song Liu
2021-09-24 17:15 ` Song Liu
2020-05-26 22:08 ` Song Liu
2020-05-27 5:40 ` Masami Hiramatsu [this message]
2020-05-27 18:40 ` Song Liu
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