Re: [PATCH net-next 0/2] net: snmp: tracepoint support for snmp

[Menglong Dong]

Hello,

On Fri, Nov 12, 2021 at 9:50 AM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
>
> On Fri, 12 Nov 2021 09:40:47 +0800 Menglong Dong wrote:
> > > I feel like I have seen this idea before. Is this your first posting?
> > >
> > > Would you mind including links to previous discussion if you're aware
> > > of any?
> >
> > This is the first time that I post this patch. Do you mean that someone
> > else has done this before? Sorry, I didn't find it~
>
> I see. Yes, I believe very similar changes were proposed in the past.
>
> I believe that concerns about the performance impact had prevented them
> from being merged.

I have found a similar post:
https://lore.kernel.org/netdev/20090303165747.GA1480@xxxxxxxxxxxxxxxxxxxxxxxxxxx/

And this is the tracepoint for kfree_skb().

I also concerns about the performance. However, with the tracepoints disabled,
they don't have any impact; with enabled, their impact is no more than the
tracepoint in kfree_skb() and consume_skb().

What's more, I have also realized another version: create tracepoint for every
statistics type, such as snmp_udp_incsumerrors, snmp_udp_rcvbuferrors, etc.
This can solve performance issue, as users can enable part of them, which
may be triggered not frequently. However, too many tracepoint are created, and
I think it may be not applicable.

Thanks!
Menglong Dong