Re: [PATCH v2] perf symbol: Remove psw_idle() from list of idle symbols

Arnaldo Carvalho de Melo
2026-03-02T18:43:48Z

On Mon, Feb 23, 2026 at 01:46:21PM -0800, Namhyung Kim wrote:
> On Thu, Feb 19, 2026 at 12:38:50PM +0100, Thomas Richter wrote:
> > Commit fa2ae4a377c0 ("s390/idle: Rewrite psw_idle() in C")
> >
> > removes symbols psw_idle() and psw_idle_exit() from the linux
> > kernel for s390. Remove them in perf tool's list of idle
> > functions. They can not be detected anymore.
>
> But I think old kernels may still run somewhere. It seems the above
> commit was merged to v6.10. Maybe we should wait some more time before
> removing it in the tool.

Agreed, using a new perf tool, say built from the tarballs made
available at:

https://www.kernel.org/pub/linux/kernel/tools/perf/v7.0.0/perf-7.0.0-rc1.tar.xz

(I will not make a rc2 available since there are no changes to the
tools/perf codebase in this rc).

On older kernels should still ignore those functions.

A suggestion for work in this area instead is to get those samples into
a special bucket, the "idle" one, and show it at some place in the
screen.

Thanks,

- Arnaldo