Re: [bpf-next 1/2] tcp: replace SOCK_DEBUG() with tcp_stats()

From: Yafang Shao
Date: Tue Feb 12 2019 - 22:05:04 EST

On Wed, Feb 13, 2019 at 10:49 AM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
> On Tue, Feb 12, 2019 at 6:15 PM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:
> >
> > Do not add more debugging stuff unless you can demonstrate
> > they actually allowed you to find a real bug and that you sent a
> > public fix for it.
> >
> > Just adding "cool stuff" in TCP stack does not please me, it is only
> > more complexity for unproven gain.
> I agree.
> I don't see why this debugging of 'abnormal TCP' cannot be done
> with kprobes and tracepoints.

kprobe is not suitable, because we have to use the line number, that's
a trouble cross all kernel versions.
Regarding tracepoints, I don't think it is a good idea to introduce
more and more tcp tracepoints and make them crowed as well.

> Instrumenting every tcp counter increment is overkill.