Re: [RFC PATCH 0/5] perf: Intel uncore pmu counting support

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Wed, 2012-03-28 at 08:49 +0200, Ingo Molnar wrote:
> * Yan, Zheng <zheng.z.yan@intel.com> wrote:
> 
> > Hi, all
> > 
> > Here is the RFC patches to add uncore counting support for Nehalem,
> > Sandy Bridge and Sandy Bridge-EP, applied on top of current tip.
> > The code is based on Lin Ming's old patches.
> > 
> > You can use 'perf stat' to access to the uncore pmu. For example:
> > perf stat -a -C 0 -e 'uncore_nhm/config=0xffff/' sleep 1
> 
> My main complaint is that that's not user friendly *AT ALL*.
> 
> You need to make this useful to mere mortals: go through the 
> SDM, categorize interesting looking events, look at how it can 
> be expressed via tooling, add a generic event where appropriate, 
> provide examples, actually *USE* it to improve the kernel or an 
> app and see the workflow as it happens and improve the tooling, 
> etc.

Easiest way out here is add a /sys/bus/event_source/devices/*/events/
directory which contains files who's name we can use as events and who's
contents are of the form we would use given the format/ stuff.

Example, suppose a westmere,

$ cat /sys/bus/event_source/devices/cpu/events/frontend_stalled_cycles
event=0x0e,umask=0x01,inv,cmask=1

I'll review the uncore patches later this week, but I suspect the whole
cpu->node mapping stuff is still not done properly.

Also, quick question, did Intel fix the SNB uncore PMI?