Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20221102160236.11696-1-iecedge@gmail.com> <20221114122255.72588f45@gandalf.local.home>
In-Reply-To: <20221114122255.72588f45@gandalf.local.home>
From:   Jianlin Lv <iecedge@gmail.com>
Date:   Tue, 15 Nov 2022 10:38:34 +0800
Message-ID: <CAFA-uR8TakkW=KoA_9RXcyw00Zj8+nNn2erSZ4Y9ULNM8ne11g@mail.gmail.com>
Subject: Re: [PATCH] tracepoint: Allow livepatch module add trace event
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     alison.schofield@intel.com, davidgow@google.com,
        thunder.leizhen@huawei.com, jianlv@ebay.com,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Tue, Nov 15, 2022 at 1:22 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Wed,  2 Nov 2022 16:02:36 +0000
> Jianlin Lv <iecedge@gmail.com> wrote:
>
> > In the case of keeping the system running, the preferred method for
> > tracing the kernel is dynamic tracing (kprobe), but the drawback of
> > this method is that events are lost, especially when tracing packages
> > in the network stack.
>
> I'm not against this change, but the above is where I'm a bit confused. H=
ow
> are events more likely to be lost with kprobes over a static event?

We have encountered a case of kprobes missing event, detailed
information can refer to the following link:
https://github.com/iovisor/bcc/issues/4198

Replacing kprobe with =E2=80=99bpf + raw tracepoint=E2=80=98,  no missing e=
vents occur.

> -- Steve