* Prarit Bhargava <pra...@redhat.com> wrote:
> Customers write system monitoring software for single systems as well as
> clusters. In load-balancing software it is useful to know how "busy" a
> core is. Unfortunately the only way to get this data is to run as root,
> or use setcap to allow userspace access for particular programs. Both of
> these options are clunky at best.
>
> This patch allows read access to the msr dev files which should be okay.
> No damage can be done by reading the MSR values and it allows non-root
> users to run system monitoring software.
>
> The turbostat code specifically checks for CAP_SYS_RAWIO, which it
> shouldn't have to and I've removed that code. Additionally I've modified
> the turbostat man page to remove documentation about configuring
> CAP_SYS_RAW_IO.
>
> Note: Write access to msr is still restricted with this patch.
>
> Cc: "H. Peter Anvin" <h...@zytor.com>
> Cc: Thomas Gleixner <t...@linutronix.de>
> Cc: Ingo Molnar <mi...@redhat.com>
> Cc: x...@kernel.org
> Cc: Len Brown <len.br...@intel.com>
> Cc: Prarit Bhargava <pra...@redhat.com>
> Cc: Dasaratharaman Chandramouli <dasaratharaman.chandramo...@intel.com>
> Signed-off-by: Prarit Bhargava <pra...@redhat.com>
> ---
> arch/x86/kernel/msr.c | 11 ++++++++---
> tools/power/x86/turbostat/turbostat.8 | 8 --------
> tools/power/x86/turbostat/turbostat.c | 17 -----------------
> 3 files changed, 8 insertions(+), 28 deletions(-)
So what's wrong with exposing them as a simplified PMU driver?
That way we only expose the ones we want to - plus tooling can use all the rich
perf features that can be used around this. (sampling, counting, call chains,
etc.)
Thanks,
Ingo
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