Re: [RFC PATCH 0/6] fprobe: Introduce fprobe function entry/exit probe

Alexei Starovoitov
2022-01-11T22:39:53Z

On Wed, Jan 12, 2022 at 12:00:17AM +0900, Masami Hiramatsu wrote:
> Hi Jiri,
>
> Here is a short series of patches, which shows what I replied
> to your series.
>
> This introduces the fprobe, the function entry/exit probe with
> multiple probe point support. This also introduces the rethook
> for hooking function return, which I cloned from kretprobe.
>
> I also rewrite your [08/13] bpf patch to use this fprobe instead
> of kprobes. I didn't tested that one, but the sample module seems
> to work. Please test bpf part with your libbpf updates.
>
> BTW, while implementing the fprobe, I introduced the per-probe
> point private data, but I'm not sure why you need it. It seems
> that data is not used from bpf...
>
> If this is good for you, I would like to proceed this with
> the rethook and rewrite the kretprobe to use the rethook to
> hook the functions. That should be much cleaner (and easy to
> prepare for the fgraph tracer integration)

What is the speed of attach/detach of thousands fprobes?