[PATCH v3.1-rc9] ARM: populate processor tag in proc-cpuinfo for Uni-processor.

[Russell King - ARM Linux]

On Thu, Oct 13, 2011 at 01:52:34PM -0700, Andrew Morton wrote:
> On Thu, 13 Oct 2011 17:48:22 +0100
> Russell King - ARM Linux <linux at arm.linux.org.uk> wrote:
> 
> > On Thu, Oct 13, 2011 at 04:43:10PM +0100, Srinivas KANDAGATLA wrote:
> > > We recently encountered issue while running cyclesoak on ARM-uniprocessor
> > > system, What we have noticed it that /proc/cpuinfo does not have
> > > "processor" tag when its uniprocessor, which looked incorrect.
> > > All the processors code in kernel do populate this tag for both uni and
> > > multi processor systems.
> > > 
> > > This patch just add processor tag for cpuinfo for ARM uni-processor systems.
> > 
> > I wonder why cyclesoak doesn't use the sysconf(_SC_NPROCESSORS_ONLN)
> > rather than implementing this functionality itself.
> > 
> > akpm?
> 
> eep, cyclesoak will soon be celebrating its eleventh birthday. 
> sysconf(_SC_NPROCESSORS_ONLN) might have existed back in those days,
> but I sure didn't know about it!

Do you have any opinion on the related issue of whether uniprocessor
kernels should include a 'processor: 0' line in their /proc/cpuinfo
to satisfy programs such as cyclesoak ?

It's worth noting that glibc's implementation for
sysconf(_SC_NPROCESSORS_ONLN) prefers reading /proc/stat and counting
the lines matching '^cpu[0-9]' as its more consistent.