Re: [PATCH net-next] trace: tcp: Add tracepoint for tcp_sendmsg()

On Wed, Feb 26, 2025 at 7:18 PM Breno Leitao [off-list ref] wrote:

Hello David,

On Wed, Feb 26, 2025 at 10:12:08AM -0700, David Ahern wrote:

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On 2/26/25 9:10 AM, Breno Leitao wrote:

quoted

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Also, if a tracepoint is added, inside of tcp_sendmsg_locked would cover
more use cases (see kernel references to it).

Agree, this seems to provide more useful information

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We have a patch for a couple years now with a tracepoint inside the

Sorry, where do you have this patch? is it downstream?

company tree. Attached. Where to put tracepoints and what arguments to
supply so that it is beneficial to multiple users is always a touchy
subject :-)

Thanks. I would like to state that this would be useful for Meta as
well.

Right now, we (Meta) are using nasty `noinline` attribute in
tcp_sendmsg() in order to make the API stable, and this tracepoint would
solve this problem avoiding the `noinline` hack. So, at least two type
of users would benefit from it.

quoted

so I have not tried to push the patch out. sock arg should
be added to it for example.

True, if it becomes a tracepoint instead of a rawtracepoint, the sock
arg might be useful.

How would you recommend me proceeding in this case?

In 2022, Menglong Dong added __fix_address

Then later , Yafang Shao  added noinline_for_tracing .

Would one of them be sufficient ?