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RE: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL client uncore

From "Liang, Kan" <kan.liang@intel.com>
Newsgroups linux.kernel
Subject RE: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL client uncore
Date 2016-04-20 16:00 +0200
Message-ID <rq0PD-jH-1@gated-at.bofh.it> (permalink)
References <roeal-5jh-1@gated-at.bofh.it> <rq0wi-aJ-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

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> On Fri, 15 Apr 2016, kan.liang@intel.com wrote:
> > +static void skl_uncore_msr_init_box(struct intel_uncore_box *box) {
> > +	if (box->pmu->pmu_idx == 0) {
> > +		wrmsrl(SKL_UNC_PERF_GLOBAL_CTL,
> > +			SNB_UNC_GLOBAL_CTL_EN |
> SKL_UNC_GLOBAL_CTL_CORE_ALL);
> > +	}
> > +}
> > +
> > +static void skl_uncore_msr_enable_box(struct intel_uncore_box *box) {
> > +	wrmsrl(SKL_UNC_PERF_GLOBAL_CTL,
> > +		SNB_UNC_GLOBAL_CTL_EN |
> SKL_UNC_GLOBAL_CTL_CORE_ALL); }
> > +
> > +static void skl_uncore_msr_disable_box(struct intel_uncore_box *box)
> > +{
> > +	wrmsrl(SKL_UNC_PERF_GLOBAL_CTL, 0);
> > +}
> > +
> > +static void skl_uncore_msr_exit_box(struct intel_uncore_box *box) {
> > +	if (box->pmu->pmu_idx == 0)
> > +		wrmsrl(SKL_UNC_PERF_GLOBAL_CTL, 0); }
> 
> The above looks broken.
> 
> init() enables the uncore machinery on the node it is running on.
> 
> start() enables the uncore machinery on the node it is running on.
> 
> stop() disables the uncore machinery on the node it is running on.
> 
> So what happens in the following case:
> 
>    start(event(box0), node0)
> 
>    start(event(box1), node0)
> 
>    stop(event(box1), node0)
> 
> The stop of the box1 events disables the whole machinery on that node and
> therefor the box0 event is wreckaged as well. Hmm?
> 

Right. How about check the SKL_UNC_PERF_GLOBAL_CTL in enable_event?
If it's cleared, we can reset it there. The drawback is that there will be an extra
rdmsrl and a possible wrmsrl. 

Thanks,
Kan

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Re: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL  client uncore Thomas Gleixner <tglx@linutronix.de> - 2016-04-20 15:40 +0200
  RE: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL  client uncore "Liang, Kan" <kan.liang@intel.com> - 2016-04-20 16:00 +0200
    RE: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL  client uncore Thomas Gleixner <tglx@linutronix.de> - 2016-04-20 17:00 +0200
      RE: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL  client uncore "Liang, Kan" <kan.liang@intel.com> - 2016-04-20 17:30 +0200
        RE: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL  client uncore Thomas Gleixner <tglx@linutronix.de> - 2016-04-21 10:10 +0200
          RE: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL  client uncore "Liang, Kan" <kan.liang@intel.com> - 2016-04-21 14:00 +0200
    Re: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL  client uncore Andi Kleen <ak@linux.intel.com> - 2016-04-20 18:40 +0200

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