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From:   =?UTF-8?B?6L+Q6L6J5bSU?= <cuiyunhui@bytedance.com>
Date:   Fri, 6 Jan 2023 10:57:26 +0800
Message-ID: <CAEEQ3wkD5bX34J36-OJ7WdHX=Y9hwFuoCtZ6_zyngKYrz3y1wQ@mail.gmail.com>
Subject: Re: [External] Re: [PATCH v2] sock: add tracepoint for send recv length
To:     Paolo Abeni <pabeni@redhat.com>
Cc:     rostedt@goodmis.org, mhiramat@kernel.org, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, duanxiongchun@bytedance.com,
        kuniyu@amazon.com, linux-kernel@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org
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On Thu, Jan 5, 2023 at 8:03 PM Paolo Abeni <pabeni@redhat.com> wrote:

> > We can obtain the information with kretprobe, but as we know, kprobe ge=
ts
> > the result by trappig in an exception, which loses performance compared
> > to tracepoint. We did a test for performance comparison. The results ar=
e
> > as follows. Time per request, sock_sendmsg(k,kr):  12.382ms,
> > tcp_send_length(tracepoint): 11.887ms=EF=BC=8Cwithout hook=EF=BC=9A11.2=
22ms
>
> 12 ms per packet? I hope there is a an error in the unit of
> measurement.
>
> I'm unsure the delta wrt kreprobe justifies this change.
>
> In any case you need to include the netdev ML into the recipients list,
> and even Cong Wang, as he provided feedback on v1.
>
> Thanks,
>
> Paolo
>

I will add the record of testing with the tool to the commit log of
v3, and then send the email to netdev ML and CongWang, thank you.