Re: [PATCHv2] arm: perf: Add event descriptions

[Will Deacon]

On Wed, Oct 07, 2015 at 11:28:18AM -0700, Drew Richardson wrote:
> Add additional information about the ARM architected hardware events
> to make counters self describing. This makes the hardware PMUs easier
> to use as perf list contains possible events instead of users having
> to refer to documentation like the ARM TRMs.
> 
> Signed-off-by: Drew Richardson <drew.richardson@xxxxxxx>
> ---
>  arch/arm/kernel/perf_event_v7.c | 96 +++++++++++++++++++++++++++++++++++++++++
>  drivers/perf/arm_pmu.c          |  1 +
>  2 files changed, 97 insertions(+)
> 
> diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c
> index 126dc679b230..6623bd0d8a1d 100644
> --- a/arch/arm/kernel/perf_event_v7.c
> +++ b/arch/arm/kernel/perf_event_v7.c
> @@ -547,6 +547,95 @@ static const unsigned scorpion_perf_cache_map[PERF_COUNT_HW_CACHE_MAX]
>  	[C(BPU)][C(OP_WRITE)][C(RESULT_MISS)] = ARMV7_PERFCTR_PC_BRANCH_MIS_PRED,
>  };
>  
> +static ssize_t armv7_event_sysfs_show(struct device *dev,
> +				      struct device_attribute *attr, char *page)
> +{
> +	struct perf_pmu_events_attr *pmu_attr;
> +
> +	pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
> +
> +	return sprintf(page, "event=0x%02llx\n", pmu_attr->id);
> +}

Can we not do this with a couple of macros, stringification of the event
code and PMU_EVENT_ATTR_STRING, therefore avoiding this function entirely?

> +#define ARMV7_EVENT_ATTR(name, config) \
> +	PMU_EVENT_ATTR(name, armv7_event_attr_##name, config, \
> +		       armv7_event_sysfs_show);
> +
> +ARMV7_EVENT_ATTR(sw_incr, ARMV7_PERFCTR_PMNC_SW_INCR);
> +ARMV7_EVENT_ATTR(l1i_cache_refill, ARMV7_PERFCTR_L1_ICACHE_REFILL);
> +ARMV7_EVENT_ATTR(l1i_tlb_refill, ARMV7_PERFCTR_ITLB_REFILL);
> +ARMV7_EVENT_ATTR(l1d_cache_refill, ARMV7_PERFCTR_L1_DCACHE_REFILL);
> +ARMV7_EVENT_ATTR(l1d_cache, ARMV7_PERFCTR_L1_DCACHE_ACCESS);
> +ARMV7_EVENT_ATTR(l1d_tlb_refill, ARMV7_PERFCTR_DTLB_REFILL);
> +ARMV7_EVENT_ATTR(ld_retired, ARMV7_PERFCTR_MEM_READ);
> +ARMV7_EVENT_ATTR(st_retired, ARMV7_PERFCTR_MEM_WRITE);
> +ARMV7_EVENT_ATTR(inst_retired, ARMV7_PERFCTR_INSTR_EXECUTED);
> +ARMV7_EVENT_ATTR(exc_taken, ARMV7_PERFCTR_EXC_TAKEN);
> +ARMV7_EVENT_ATTR(exc_return, ARMV7_PERFCTR_EXC_EXECUTED);
> +ARMV7_EVENT_ATTR(cid_write_retired, ARMV7_PERFCTR_CID_WRITE);
> +ARMV7_EVENT_ATTR(pc_write_retired, ARMV7_PERFCTR_PC_WRITE);
> +ARMV7_EVENT_ATTR(br_immed_retired, ARMV7_PERFCTR_PC_IMM_BRANCH);
> +ARMV7_EVENT_ATTR(br_return_retired, ARMV7_PERFCTR_PC_PROC_RETURN);
> +ARMV7_EVENT_ATTR(unaligned_ldst_retired, ARMV7_PERFCTR_MEM_UNALIGNED_ACCESS);
> +ARMV7_EVENT_ATTR(br_mis_pred, ARMV7_PERFCTR_PC_BRANCH_MIS_PRED);
> +ARMV7_EVENT_ATTR(cpu_cycles, ARMV7_PERFCTR_CLOCK_CYCLES);
> +ARMV7_EVENT_ATTR(br_pred, ARMV7_PERFCTR_PC_BRANCH_PRED);
> +ARMV7_EVENT_ATTR(mem_access, ARMV7_PERFCTR_MEM_ACCESS);
> +ARMV7_EVENT_ATTR(l1i_cache, ARMV7_PERFCTR_L1_ICACHE_ACCESS);
> +ARMV7_EVENT_ATTR(l1d_cache_wb, ARMV7_PERFCTR_L1_DCACHE_WB);
> +ARMV7_EVENT_ATTR(l2d_cache, ARMV7_PERFCTR_L2_CACHE_ACCESS);
> +ARMV7_EVENT_ATTR(l2d_cache_refill, ARMV7_PERFCTR_L2_CACHE_REFILL);
> +ARMV7_EVENT_ATTR(l2d_cache_wb, ARMV7_PERFCTR_L2_CACHE_WB);
> +ARMV7_EVENT_ATTR(bus_access, ARMV7_PERFCTR_BUS_ACCESS);
> +ARMV7_EVENT_ATTR(memory_error, ARMV7_PERFCTR_MEM_ERROR);
> +ARMV7_EVENT_ATTR(inst_spec, ARMV7_PERFCTR_INSTR_SPEC);
> +ARMV7_EVENT_ATTR(ttbr_write_retired, ARMV7_PERFCTR_TTBR_WRITE);
> +ARMV7_EVENT_ATTR(bus_cycles, ARMV7_PERFCTR_BUS_CYCLES);
> +
> +static struct attribute *armv7_pmuv2_event_attrs[] = {
> +	&armv7_event_attr_sw_incr.attr.attr,
> +	&armv7_event_attr_l1i_cache_refill.attr.attr,
> +	&armv7_event_attr_l1i_tlb_refill.attr.attr,
> +	&armv7_event_attr_l1d_cache_refill.attr.attr,
> +	&armv7_event_attr_l1d_cache.attr.attr,
> +	&armv7_event_attr_l1d_tlb_refill.attr.attr,
> +	&armv7_event_attr_ld_retired.attr.attr,
> +	&armv7_event_attr_st_retired.attr.attr,
> +	&armv7_event_attr_inst_retired.attr.attr,
> +	&armv7_event_attr_exc_taken.attr.attr,
> +	&armv7_event_attr_exc_return.attr.attr,
> +	&armv7_event_attr_cid_write_retired.attr.attr,
> +	&armv7_event_attr_pc_write_retired.attr.attr,
> +	&armv7_event_attr_br_immed_retired.attr.attr,
> +	&armv7_event_attr_br_return_retired.attr.attr,
> +	&armv7_event_attr_unaligned_ldst_retired.attr.attr,
> +	&armv7_event_attr_br_mis_pred.attr.attr,
> +	&armv7_event_attr_cpu_cycles.attr.attr,
> +	&armv7_event_attr_br_pred.attr.attr,
> +	&armv7_event_attr_mem_access.attr.attr,
> +	&armv7_event_attr_l1i_cache.attr.attr,
> +	&armv7_event_attr_l1d_cache_wb.attr.attr,
> +	&armv7_event_attr_l2d_cache.attr.attr,
> +	&armv7_event_attr_l2d_cache_refill.attr.attr,
> +	&armv7_event_attr_l2d_cache_wb.attr.attr,
> +	&armv7_event_attr_bus_access.attr.attr,
> +	&armv7_event_attr_memory_error.attr.attr,
> +	&armv7_event_attr_inst_spec.attr.attr,
> +	&armv7_event_attr_ttbr_write_retired.attr.attr,
> +	&armv7_event_attr_bus_cycles.attr.attr,
> +	NULL
> +};
> +
> +static struct attribute_group armv7_pmuv2_events_attr_group = {
> +	.name = "events",
> +	.attrs = armv7_pmuv2_event_attrs,
> +};
> +
> +static const struct attribute_group *armv7_pmuv2_attr_groups[] = {
> +	&armv7_pmuv2_events_attr_group,
> +	NULL
> +};
> +
>  /*
>   * Perf Events' indices
>   */
> @@ -1085,6 +1174,7 @@ static int armv7_a8_pmu_init(struct arm_pmu *cpu_pmu)
>  	armv7pmu_init(cpu_pmu);
>  	cpu_pmu->name		= "armv7_cortex_a8";
>  	cpu_pmu->map_event	= armv7_a8_map_event;
> +	cpu_pmu->pmu.attr_groups = armv7_pmuv2_attr_groups;
>  	return armv7_probe_num_events(cpu_pmu);
>  }
>  
> @@ -1093,6 +1183,7 @@ static int armv7_a9_pmu_init(struct arm_pmu *cpu_pmu)
>  	armv7pmu_init(cpu_pmu);
>  	cpu_pmu->name		= "armv7_cortex_a9";
>  	cpu_pmu->map_event	= armv7_a9_map_event;
> +	cpu_pmu->pmu.attr_groups = armv7_pmuv2_attr_groups;

I didn't think these guys supported PMUv2, or is that backwards compatible
with the older event definitions?

Also, would you be able to do something similar for AArch64 too, please?
(take a look at our for-next/core branch for the latest perf changes).

Thanks,

Will
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