From: Masami Hiramatsu <mhiramat@kernel.org>
To: Jiri Olsa <jolsa@redhat.com>
Cc: 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 00/13] kprobe/bpf: Add support to attach multiple kprobes
Date: Thu, 6 Jan 2022 00:24:35 +0900 [thread overview]
Message-ID: <20220106002435.d73e4010c93462fbee9ef074@kernel.org> (raw)
In-Reply-To: <20220104080943.113249-1-jolsa@kernel.org>
On Tue, 4 Jan 2022 09:09:30 +0100
Jiri Olsa <jolsa@redhat.com> wrote:
> hi,
> adding support to attach multiple kprobes within single syscall
> and speed up attachment of many kprobes.
>
> The previous attempt [1] wasn't fast enough, so coming with new
> approach that adds new kprobe interface.
Yes, since register_kprobes() just registers multiple kprobes on
array. This is designed for dozens of kprobes.
> The attachment speed of of this approach (tested in bpftrace)
> is now comparable to ftrace tracer attachment speed.. fast ;-)
Yes, because that if ftrace, not kprobes.
> The limit of this approach is forced by using ftrace as attach
> layer, so it allows only kprobes on function's entry (plus
> return probes).
Note that you also need to multiply the number of instances.
>
> This patchset contains:
> - kprobes support to register multiple kprobes with current
> kprobe API (patches 1 - 8)
> - bpf support ot create new kprobe link allowing to attach
> multiple addresses (patches 9 - 14)
>
> We don't need to care about multiple probes on same functions
> because it's taken care on the ftrace_ops layer.
Hmm, I think there may be a time to split the "kprobe as an
interface for the software breakpoint" and "kprobe as a wrapper
interface for the callbacks of various instrumentations", like
'raw_kprobe'(or kswbp) and 'kprobes'.
And this may be called as 'fprobe' as ftrace_ops wrapper.
(But if the bpf is enough flexible, this kind of intermediate layer
may not be needed, it can use ftrace_ops directly, eventually)
Jiri, have you already considered to use ftrace_ops from the
bpf directly? Are there any issues?
(bpf depends on 'kprobe' widely?)
Thank you,
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2022-01-05 15:24 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 [this message]
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
2022-01-12 11:08 ` Masami Hiramatsu
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