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Date: Wed, 20 Apr 2016 13:56:32 +0000 From: "Liang, Kan" <kan.liang@...el.com> To: Thomas Gleixner <tglx@...utronix.de> CC: "peterz@...radead.org" <peterz@...radead.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "ak@...ux.intel.com" <ak@...ux.intel.com>, "eranian@...gle.com" <eranian@...gle.com> Subject: RE: [PATCH 1/1] perf/x86/intel/uncore: Add support for Intel SKL client uncore > On Fri, 15 Apr 2016, kan.liang@...el.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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