Date:	Thu, 7 Feb 2013 11:57:03 -0600
From:	Jacob Shin <jacob.shin@....com>
To:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, <x86@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC:	Paul Mackerras <paulus@...ba.org>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	Stephane Eranian <eranian@...gle.com>,
	Jiri Olsa <jolsa@...hat.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/6] perf, amd: Enable northbridge performance counters
 on AMD family 15h

On Wed, Feb 06, 2013 at 11:26:29AM -0600, Jacob Shin wrote:
> On AMD family 15h processors, there are 4 new performance counters
> (in addition to 6 core performance counters) that can be used for
> counting northbridge events (i.e. DRAM accesses). Their bit fields are
> almost identical to the core performance counters. However, unlike the
> core performance counters, these MSRs are shared between multiple
> cores (that share the same northbridge). We will reuse the same code
> path as existing family 10h northbridge event constraints handler
> logic to enforce this sharing.
> 
> Signed-off-by: Jacob Shin <jacob.shin@....com>

Hi Ingo, could you please apply this one to tip as well? I recieved
tip-bot emails for all other patches in this series except for this
last one 6/6.

Or was that intentional? If so, what other changes are required/
recommended?

Thanks!

-Jacob

> ---
>  arch/x86/include/asm/cpufeature.h     |    2 +
>  arch/x86/include/asm/perf_event.h     |    9 ++
>  arch/x86/include/uapi/asm/msr-index.h |    2 +
>  arch/x86/kernel/cpu/perf_event_amd.c  |  171 +++++++++++++++++++++++++++++----
>  4 files changed, 164 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
> index 2d9075e..93fe929 100644
> --- a/arch/x86/include/asm/cpufeature.h
> +++ b/arch/x86/include/asm/cpufeature.h
> @@ -167,6 +167,7 @@
>  #define X86_FEATURE_TBM		(6*32+21) /* trailing bit manipulations */
>  #define X86_FEATURE_TOPOEXT	(6*32+22) /* topology extensions CPUID leafs */
>  #define X86_FEATURE_PERFCTR_CORE (6*32+23) /* core performance counter extensions */
> +#define X86_FEATURE_PERFCTR_NB  (6*32+24) /* NB performance counter extensions */
>  
>  /*
>   * Auxiliary flags: Linux defined - For features scattered in various
> @@ -309,6 +310,7 @@ extern const char * const x86_power_flags[32];
>  #define cpu_has_hypervisor	boot_cpu_has(X86_FEATURE_HYPERVISOR)
>  #define cpu_has_pclmulqdq	boot_cpu_has(X86_FEATURE_PCLMULQDQ)
>  #define cpu_has_perfctr_core	boot_cpu_has(X86_FEATURE_PERFCTR_CORE)
> +#define cpu_has_perfctr_nb	boot_cpu_has(X86_FEATURE_PERFCTR_NB)
>  #define cpu_has_cx8		boot_cpu_has(X86_FEATURE_CX8)
>  #define cpu_has_cx16		boot_cpu_has(X86_FEATURE_CX16)
>  #define cpu_has_eager_fpu	boot_cpu_has(X86_FEATURE_EAGER_FPU)
> diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
> index 2234eaaec..57cb634 100644
> --- a/arch/x86/include/asm/perf_event.h
> +++ b/arch/x86/include/asm/perf_event.h
> @@ -29,9 +29,14 @@
>  #define ARCH_PERFMON_EVENTSEL_INV			(1ULL << 23)
>  #define ARCH_PERFMON_EVENTSEL_CMASK			0xFF000000ULL
>  
> +#define AMD64_EVENTSEL_INT_CORE_ENABLE			(1ULL << 36)
>  #define AMD64_EVENTSEL_GUESTONLY			(1ULL << 40)
>  #define AMD64_EVENTSEL_HOSTONLY				(1ULL << 41)
>  
> +#define AMD64_EVENTSEL_INT_CORE_SEL_SHIFT		37
> +#define AMD64_EVENTSEL_INT_CORE_SEL_MASK		\
> +	(0xFULL << AMD64_EVENTSEL_INT_CORE_SEL_SHIFT)
> +
>  #define AMD64_EVENTSEL_EVENT	\
>  	(ARCH_PERFMON_EVENTSEL_EVENT | (0x0FULL << 32))
>  #define INTEL_ARCH_EVENT_MASK	\
> @@ -46,8 +51,12 @@
>  #define AMD64_RAW_EVENT_MASK		\
>  	(X86_RAW_EVENT_MASK          |  \
>  	 AMD64_EVENTSEL_EVENT)
> +#define AMD64_RAW_EVENT_MASK_NB		\
> +	(AMD64_EVENTSEL_EVENT        |  \
> +	 ARCH_PERFMON_EVENTSEL_UMASK)
>  #define AMD64_NUM_COUNTERS				4
>  #define AMD64_NUM_COUNTERS_CORE				6
> +#define AMD64_NUM_COUNTERS_NB				4
>  
>  #define ARCH_PERFMON_UNHALTED_CORE_CYCLES_SEL		0x3c
>  #define ARCH_PERFMON_UNHALTED_CORE_CYCLES_UMASK		(0x00 << 8)
> diff --git a/arch/x86/include/uapi/asm/msr-index.h b/arch/x86/include/uapi/asm/msr-index.h
> index 1031604..27c05d2 100644
> --- a/arch/x86/include/uapi/asm/msr-index.h
> +++ b/arch/x86/include/uapi/asm/msr-index.h
> @@ -195,6 +195,8 @@
>  /* Fam 15h MSRs */
>  #define MSR_F15H_PERF_CTL		0xc0010200
>  #define MSR_F15H_PERF_CTR		0xc0010201
> +#define MSR_F15H_NB_PERF_CTL		0xc0010240
> +#define MSR_F15H_NB_PERF_CTR		0xc0010241
>  
>  /* Fam 10h MSRs */
>  #define MSR_FAM10H_MMIO_CONF_BASE	0xc0010058
> diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c
> index 05462f0..dfdab42 100644
> --- a/arch/x86/kernel/cpu/perf_event_amd.c
> +++ b/arch/x86/kernel/cpu/perf_event_amd.c
> @@ -132,11 +132,14 @@ static u64 amd_pmu_event_map(int hw_event)
>  	return amd_perfmon_event_map[hw_event];
>  }
>  
> +static struct event_constraint *amd_nb_event_constraint;
> +
>  /*
>   * Previously calculated offsets
>   */
>  static unsigned int event_offsets[X86_PMC_IDX_MAX] __read_mostly;
>  static unsigned int count_offsets[X86_PMC_IDX_MAX] __read_mostly;
> +static unsigned int rdpmc_indexes[X86_PMC_IDX_MAX] __read_mostly;
>  
>  /*
>   * Legacy CPUs:
> @@ -144,10 +147,14 @@ static unsigned int count_offsets[X86_PMC_IDX_MAX] __read_mostly;
>   *
>   * CPUs with core performance counter extensions:
>   *   6 counters starting at 0xc0010200 each offset by 2
> + *
> + * CPUs with north bridge performance counter extensions:
> + *   4 additional counters starting at 0xc0010240 each offset by 2
> + *   (indexed right above either one of the above core counters)
>   */
>  static inline int amd_pmu_addr_offset(int index, bool eventsel)
>  {
> -	int offset;
> +	int offset, first, base;
>  
>  	if (!index)
>  		return index;
> @@ -160,7 +167,23 @@ static inline int amd_pmu_addr_offset(int index, bool eventsel)
>  	if (offset)
>  		return offset;
>  
> -	if (!cpu_has_perfctr_core)
> +	if (amd_nb_event_constraint &&
> +	    test_bit(index, amd_nb_event_constraint->idxmsk)) {
> +		/*
> +		 * calculate the offset of NB counters with respect to
> +		 * base eventsel or perfctr
> +		 */
> +
> +		first = find_first_bit(amd_nb_event_constraint->idxmsk,
> +				       X86_PMC_IDX_MAX);
> +
> +		if (eventsel)
> +			base = MSR_F15H_NB_PERF_CTL - x86_pmu.eventsel;
> +		else
> +			base = MSR_F15H_NB_PERF_CTR - x86_pmu.perfctr;
> +
> +		offset = base + ((index - first) << 1);
> +	} else if (!cpu_has_perfctr_core)
>  		offset = index;
>  	else
>  		offset = index << 1;
> @@ -175,24 +198,36 @@ static inline int amd_pmu_addr_offset(int index, bool eventsel)
>  
>  static inline int amd_pmu_rdpmc_index(int index)
>  {
> -	return index;
> -}
> +	int ret, first;
>  
> -static int amd_pmu_hw_config(struct perf_event *event)
> -{
> -	int ret;
> +	if (!index)
> +		return index;
>  
> -	/* pass precise event sampling to ibs: */
> -	if (event->attr.precise_ip && get_ibs_caps())
> -		return -ENOENT;
> +	ret = rdpmc_indexes[index];
>  
> -	ret = x86_pmu_hw_config(event);
>  	if (ret)
>  		return ret;
>  
> -	if (has_branch_stack(event))
> -		return -EOPNOTSUPP;
> +	if (amd_nb_event_constraint &&
> +	    test_bit(index, amd_nb_event_constraint->idxmsk)) {
> +		/*
> +		 * according to the mnual, ECX value of the NB counters is
> +		 * the index of the NB counter (0, 1, 2 or 3) plus 6
> +		 */
> +
> +		first = find_first_bit(amd_nb_event_constraint->idxmsk,
> +				       X86_PMC_IDX_MAX);
> +		ret = index - first + 6;
> +	} else
> +		ret = index;
> +
> +	rdpmc_indexes[index] = ret;
>  
> +	return ret;
> +}
> +
> +static int amd_core_hw_config(struct perf_event *event)
> +{
>  	if (event->attr.exclude_host && event->attr.exclude_guest)
>  		/*
>  		 * When HO == GO == 1 the hardware treats that as GO == HO == 0
> @@ -206,10 +241,33 @@ static int amd_pmu_hw_config(struct perf_event *event)
>  	else if (event->attr.exclude_guest)
>  		event->hw.config |= AMD64_EVENTSEL_HOSTONLY;
>  
> -	if (event->attr.type != PERF_TYPE_RAW)
> -		return 0;
> +	return 0;
> +}
>  
> -	event->hw.config |= event->attr.config & AMD64_RAW_EVENT_MASK;
> +/*
> + * NB counters do not support the following event select bits:
> + *   Host/Guest only
> + *   Counter mask
> + *   Invert counter mask
> + *   Edge detect
> + *   OS/User mode
> + */
> +static int amd_nb_hw_config(struct perf_event *event)
> +{
> +	/* for NB, we only allow system wide counting mode */
> +	if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
> +		return -EINVAL;
> +
> +	if (event->attr.exclude_user || event->attr.exclude_kernel ||
> +	    event->attr.exclude_host || event->attr.exclude_guest)
> +		return -EINVAL;
> +
> +	event->hw.config &= ~(ARCH_PERFMON_EVENTSEL_USR |
> +			      ARCH_PERFMON_EVENTSEL_OS);
> +
> +	if (event->hw.config & ~(AMD64_RAW_EVENT_MASK_NB |
> +				 ARCH_PERFMON_EVENTSEL_INT))
> +		return -EINVAL;
>  
>  	return 0;
>  }
> @@ -227,6 +285,11 @@ static inline int amd_is_nb_event(struct hw_perf_event *hwc)
>  	return (hwc->config & 0xe0) == 0xe0;
>  }
>  
> +static inline int amd_is_perfctr_nb_event(struct hw_perf_event *hwc)
> +{
> +	return amd_nb_event_constraint && amd_is_nb_event(hwc);
> +}
> +
>  static inline int amd_has_nb(struct cpu_hw_events *cpuc)
>  {
>  	struct amd_nb *nb = cpuc->amd_nb;
> @@ -234,6 +297,30 @@ static inline int amd_has_nb(struct cpu_hw_events *cpuc)
>  	return nb && nb->nb_id != -1;
>  }
>  
> +static int amd_pmu_hw_config(struct perf_event *event)
> +{
> +	int ret;
> +
> +	/* pass precise event sampling to ibs: */
> +	if (event->attr.precise_ip && get_ibs_caps())
> +		return -ENOENT;
> +
> +	if (has_branch_stack(event))
> +		return -EOPNOTSUPP;
> +
> +	ret = x86_pmu_hw_config(event);
> +	if (ret)
> +		return ret;
> +
> +	if (event->attr.type == PERF_TYPE_RAW)
> +		event->hw.config |= event->attr.config & AMD64_RAW_EVENT_MASK;
> +
> +	if (amd_is_perfctr_nb_event(&event->hw))
> +		return amd_nb_hw_config(event);
> +
> +	return amd_core_hw_config(event);
> +}
> +
>  static void __amd_put_nb_event_constraints(struct cpu_hw_events *cpuc,
>  					   struct perf_event *event)
>  {
> @@ -254,6 +341,19 @@ static void __amd_put_nb_event_constraints(struct cpu_hw_events *cpuc,
>  	}
>  }
>  
> +static void amd_nb_interrupt_hw_config(struct hw_perf_event *hwc)
> +{
> +	int core_id = cpu_data(smp_processor_id()).cpu_core_id;
> +
> +	/* deliver interrupts only to this core */
> +	if (hwc->config & ARCH_PERFMON_EVENTSEL_INT) {
> +		hwc->config |= AMD64_EVENTSEL_INT_CORE_ENABLE;
> +		hwc->config &= ~AMD64_EVENTSEL_INT_CORE_SEL_MASK;
> +		hwc->config |= (u64)(core_id) <<
> +			AMD64_EVENTSEL_INT_CORE_SEL_SHIFT;
> +	}
> +}
> +
>   /*
>    * AMD64 NorthBridge events need special treatment because
>    * counter access needs to be synchronized across all cores
> @@ -299,6 +399,12 @@ __amd_get_nb_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *ev
>  	struct perf_event *old;
>  	int idx, new = -1;
>  
> +	if (!c)
> +		c = &unconstrained;
> +
> +	if (cpuc->is_fake)
> +		return c;
> +
>  	/*
>  	 * detect if already present, if so reuse
>  	 *
> @@ -335,6 +441,9 @@ __amd_get_nb_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *ev
>  	if (new == -1)
>  		return &emptyconstraint;
>  
> +	if (amd_is_perfctr_nb_event(hwc))
> +		amd_nb_interrupt_hw_config(hwc);
> +
>  	return &nb->event_constraints[new];
>  }
>  
> @@ -434,7 +543,8 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
>  	if (!(amd_has_nb(cpuc) && amd_is_nb_event(&event->hw)))
>  		return &unconstrained;
>  
> -	return __amd_get_nb_event_constraints(cpuc, event, &unconstrained);
> +	return __amd_get_nb_event_constraints(cpuc, event,
> +					      amd_nb_event_constraint);
>  }
>  
>  static void amd_put_event_constraints(struct cpu_hw_events *cpuc,
> @@ -533,6 +643,9 @@ static struct event_constraint amd_f15_PMC30 = EVENT_CONSTRAINT_OVERLAP(0, 0x09,
>  static struct event_constraint amd_f15_PMC50 = EVENT_CONSTRAINT(0, 0x3F, 0);
>  static struct event_constraint amd_f15_PMC53 = EVENT_CONSTRAINT(0, 0x38, 0);
>  
> +static struct event_constraint amd_NBPMC96 = EVENT_CONSTRAINT(0, 0x3C0, 0);
> +static struct event_constraint amd_NBPMC74 = EVENT_CONSTRAINT(0, 0xF0, 0);
> +
>  static struct event_constraint *
>  amd_get_event_constraints_f15h(struct cpu_hw_events *cpuc, struct perf_event *event)
>  {
> @@ -598,8 +711,8 @@ amd_get_event_constraints_f15h(struct cpu_hw_events *cpuc, struct perf_event *ev
>  			return &amd_f15_PMC20;
>  		}
>  	case AMD_EVENT_NB:
> -		/* not yet implemented */
> -		return &emptyconstraint;
> +		return __amd_get_nb_event_constraints(cpuc, event,
> +						      amd_nb_event_constraint);
>  	default:
>  		return &emptyconstraint;
>  	}
> @@ -647,7 +760,7 @@ static __initconst const struct x86_pmu amd_pmu = {
>  
>  static int setup_event_constraints(void)
>  {
> -	if (boot_cpu_data.x86 >= 0x15)
> +	if (boot_cpu_data.x86 == 0x15)
>  		x86_pmu.get_event_constraints = amd_get_event_constraints_f15h;
>  	return 0;
>  }
> @@ -677,6 +790,23 @@ static int setup_perfctr_core(void)
>  	return 0;
>  }
>  
> +static int setup_perfctr_nb(void)
> +{
> +	if (!cpu_has_perfctr_nb)
> +		return -ENODEV;
> +
> +	x86_pmu.num_counters += AMD64_NUM_COUNTERS_NB;
> +
> +	if (cpu_has_perfctr_core)
> +		amd_nb_event_constraint = &amd_NBPMC96;
> +	else
> +		amd_nb_event_constraint = &amd_NBPMC74;
> +
> +	printk(KERN_INFO "perf: AMD northbridge performance counters detected\n");
> +
> +	return 0;
> +}
> +
>  __init int amd_pmu_init(void)
>  {
>  	/* Performance-monitoring supported from K7 and later: */
> @@ -687,6 +817,7 @@ __init int amd_pmu_init(void)
>  
>  	setup_event_constraints();
>  	setup_perfctr_core();
> +	setup_perfctr_nb();
>  
>  	/* Events are common for all AMDs */
>  	memcpy(hw_cache_event_ids, amd_hw_cache_event_ids,
> -- 
> 1.7.9.5
> 

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