Re: [RFC 00/48] perf tools: Introduce data type profiling (v1)

From: Ingo Molnar
Date: Thu Oct 12 2023 - 14:33:13 EST



* Namhyung Kim <namhyung@xxxxxxxxxx> wrote:

> > Could we perhaps add an IP filter to perf events to get this built-in?
> > Perhaps attr->exclude_user would achieve something similar?
>
> Unfortunately IBS doesn't support privilege filters IIUC. Maybe
> we could add a general filtering logic in the NMI handler but I'm
> afraid it can complicate the code and maybe slow it down a bit.
> Probably it's ok to have only a simple privilege filter by IP range.

It will still be so much faster than moving it through the BPF machinery,
and bonus points if we merge this into the existing privilege-domain
filtering ABI, so no magic 0x800000000000 constants are needed.

'Overhead' to other usecases shouldn't be much more than a single branch
somewhere.

Thanks,

Ingo