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

[Namhyung Kim <namhyung@xxxxxxxxxx>]

On Thu, Oct 12, 2023 at 11:33 AM Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
>
> * 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.

Ok, maybe overhead is not a concern.  But users need to pass the
filter expression to the kernel.

Thanks,
Namhyung