Re: [RFC PATCH 2/3] Implement sysfs based cpuinfo for x86 cpus.

[Thomas Renninger]

On Thursday, June 08, 2017 08:24:01 PM Greg KH wrote:
> On Thu, Jun 08, 2017 at 06:56:14PM +0200, Felix Schnizlein wrote:
> > ---
> >  arch/x86/kernel/Makefile        |   1 +
> >  arch/x86/kernel/cpuinfo_sysfs.c | 166 
++++++++++++++++++++++++++++++++++++++++
> >  drivers/base/cpuinfo.c          |   4 -
> >  3 files changed, 167 insertions(+), 4 deletions(-)
> >  create mode 100644 arch/x86/kernel/cpuinfo_sysfs.c
> > 
> 
> When you add new sysfs entries, you have to also add new
> Documentation/ABI/ entries.

This one seem to be rather unmaintained?
There even is:
Documentation/ABI/stable/sysfs-devices-system-cpu
this patchset would have to add:
Documentation/ABI/stable/sysfs-devices-system-cpu-cpuinfo
then.

But:
Documentation/ABI/stable/sysfs-devices-system-cpu
describes
/sys/devices/system/cpu/dscr_default
and
/sys/devices/system/cpu/cpu[0-9]+/dscr

which I have never seen.

Much more important values in there like:
/sys/devices/system/cpu/topology
/sys/devices/system/cpu/microcode
/sys/devices/system/cpu/cpuidle
/sys/devices/system/cpu/cpufreq
/sys/devices/system/cpu/{online,offline}

are not described there at all.

I wonder whether .../cpu/dscr_default still exists in the
kernel, a quick grep did not reveal anything.
A
Source:
tag would be a nice non-optional addition in the README.

We can also send definitions for topology/microcode/cache/..
to catch up a bit there again, not sure that makes much sense.

Be aware that the output of /proc/cpuinfo is rather arbitrary
depending on architecure and some build options.

      Thomas