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From: Masami Hiramatsu <mhiramat@kernel.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	lkml <linux-kernel@vger.kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
	"David S . Miller" <davem@davemloft.net>
Subject: Re: [RFC PATCH 0/6] fprobe: Introduce fprobe function entry/exit probe
Date: Wed, 12 Jan 2022 16:33:53 +0900	[thread overview]
Message-ID: <20220112163353.4da6a6b9c6eef69dbda50324@kernel.org> (raw)
In-Reply-To: <20220111223944.jbi3mxedwifxwyz5@ast-mbp.lan>

Hi Alexei,

On Tue, 11 Jan 2022 14:39:44 -0800
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:

> On Wed, Jan 12, 2022 at 12:00:17AM +0900, Masami Hiramatsu wrote:
> > Hi Jiri,
> > 
> > Here is a short series of patches, which shows what I replied
> > to your series.
> > 
> > This introduces the fprobe, the function entry/exit probe with
> > multiple probe point support. This also introduces the rethook
> > for hooking function return, which I cloned from kretprobe.
> > 
> > I also rewrite your [08/13] bpf patch to use this fprobe instead
> > of kprobes. I didn't tested that one, but the sample module seems
> > to work. Please test bpf part with your libbpf updates.
> > 
> > BTW, while implementing the fprobe, I introduced the per-probe
> > point private data, but I'm not sure why you need it. It seems
> > that data is not used from bpf...
> > 
> > If this is good for you, I would like to proceed this with
> > the rethook and rewrite the kretprobe to use the rethook to
> > hook the functions. That should be much cleaner (and easy to
> > prepare for the fgraph tracer integration)
> 
> What is the speed of attach/detach of thousands fprobes?

I've treaked my example module and it shows below result;

/lib/modules/5.16.0-rc4+/kernel/samples/fprobe # time insmod ./fprobe_example.ko
 symbol='btrfs_*'
[  187.095925] fprobe_init: 1028 symbols found
[  188.521694] fprobe_init: Planted fprobe at btrfs_*
real	0m 1.47s
user	0m 0.00s
sys	0m 1.36s

I think using ftrace_set_filter_ips() can make it faster.
(maybe it needs to drop per-probe point private data, that
prevents fprobe to use that interface)

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>

  reply	other threads:[~2022-01-12  7:34 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-04  8:09 [RFC 00/13] kprobe/bpf: Add support to attach multiple kprobes Jiri Olsa
2022-01-04  8:09 ` [PATCH 01/13] ftrace: Add ftrace_set_filter_ips function Jiri Olsa
2022-01-04  8:09 ` [PATCH 02/13] kprobe: Keep traced function address Jiri Olsa
2022-01-05 14:32   ` Masami Hiramatsu
2022-01-06  8:30     ` Jiri Olsa
2022-01-06  4:30   ` Andrii Nakryiko
2022-01-06  8:31     ` Jiri Olsa
2022-01-04  8:09 ` [PATCH 03/13] kprobe: Add support to register multiple ftrace kprobes Jiri Olsa
2022-01-05 15:00   ` Masami Hiramatsu
2022-01-04  8:09 ` [PATCH 04/13] kprobe: Add support to register multiple ftrace kretprobes Jiri Olsa
2022-01-04  8:09 ` [PATCH 05/13] kprobe: Allow to get traced function address for multi ftrace kprobes Jiri Olsa
2022-01-06  4:30   ` Andrii Nakryiko
2022-01-04  8:09 ` [PATCH 06/13] samples/kprobes: Add support for multi kprobe interface Jiri Olsa
2022-01-04  8:09 ` [PATCH 07/13] samples/kprobes: Add support for multi kretprobe interface Jiri Olsa
2022-01-04  8:09 ` [PATCH 08/13] bpf: Add kprobe link for attaching raw kprobes Jiri Olsa
2022-01-06  4:30   ` Andrii Nakryiko
2022-01-06  8:41     ` Jiri Olsa
2022-01-06 16:32       ` Alexei Starovoitov
2022-01-06 21:53         ` Andrii Nakryiko
2022-01-04  8:09 ` [PATCH 09/13] libbpf: Add libbpf__kallsyms_parse function Jiri Olsa
2022-01-04  8:09 ` [PATCH 10/13] libbpf: Add bpf_link_create support for multi kprobes Jiri Olsa
2022-01-04  8:09 ` [PATCH 11/13] libbpf: Add bpf_program__attach_kprobe_opts " Jiri Olsa
2022-01-04  8:09 ` [PATCH 12/13] selftest/bpf: Add raw kprobe attach test Jiri Olsa
2022-01-04  8:09 ` [PATCH 13/13] selftest/bpf: Add bpf_cookie test for raw_k[ret]probe Jiri Olsa
2022-01-04 18:53 ` [RFC 00/13] kprobe/bpf: Add support to attach multiple kprobes Alexei Starovoitov
2022-01-05  9:15   ` Jiri Olsa
2022-01-05 15:24 ` Masami Hiramatsu
2022-01-06  8:29   ` Jiri Olsa
2022-01-06 13:59     ` Masami Hiramatsu
2022-01-06 14:57       ` Jiri Olsa
2022-01-07  5:42         ` Masami Hiramatsu
2022-01-06 15:02       ` Steven Rostedt
2022-01-06 17:40       ` Alexei Starovoitov
2022-01-06 23:52         ` Masami Hiramatsu
2022-01-07  0:20           ` Alexei Starovoitov
2022-01-07 12:55             ` Masami Hiramatsu
2022-01-11 15:00 ` [RFC PATCH 0/6] fprobe: Introduce fprobe function entry/exit probe Masami Hiramatsu
2022-01-11 15:00   ` [RFC PATCH 1/6] fprobe: Add ftrace based probe APIs Masami Hiramatsu
2022-01-11 15:00   ` [RFC PATCH 2/6] rethook: Add a generic return hook Masami Hiramatsu
2022-01-11 15:00   ` [RFC PATCH 3/6] rethook: x86: Add rethook x86 implementation Masami Hiramatsu
2022-01-11 15:01   ` [RFC PATCH 4/6] fprobe: Add exit_handler support Masami Hiramatsu
2022-01-11 15:01   ` [RFC PATCH 5/6] fprobe: Add sample program for fprobe Masami Hiramatsu
2022-01-11 15:01   ` [RFC PATCH 6/6] bpf: Add kprobe link for attaching raw kprobes Masami Hiramatsu
2022-01-11 22:39   ` [RFC PATCH 0/6] fprobe: Introduce fprobe function entry/exit probe Alexei Starovoitov
2022-01-12  7:33     ` Masami Hiramatsu [this message]
2022-01-12 11:08       ` Masami Hiramatsu

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