On Thu, Jun 09, 2016 at 05:23:30PM -0500, Jeremy Linton wrote:
> On systems with multiple PMU types the PMU to CPU affinity
> needs to be detected and set. The CPU to interrupt affinity
> should also be set.
>
> Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
> ---
> drivers/perf/arm_pmu.c | 52 ++++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 42 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
> index fee4be0e8..865a9db 100644
> --- a/drivers/perf/arm_pmu.c
> +++ b/drivers/perf/arm_pmu.c
> @@ -11,6 +11,7 @@
> */
> #define pr_fmt(fmt) "hw perfevents: " fmt
>
> +#include <linux/acpi.h>
> #include <linux/bitmap.h>
> #include <linux/cpumask.h>
> #include <linux/cpu_pm.h>
> @@ -24,6 +25,7 @@
> #include <linux/irq.h>
> #include <linux/irqdesc.h>
>
> +#include <asm/cpu.h>
> #include <asm/cputype.h>
> #include <asm/irq_regs.h>
>
> @@ -872,25 +874,56 @@ static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
> }
>
> /*
> - * CPU PMU identification and probing.
> + * CPU PMU identification and probing. Its possible to have
> + * multiple CPU types in an ARM machine. Assure that we are
> + * picking the right PMU types based on the CPU in question
> */
> -static int probe_current_pmu(struct arm_pmu *pmu,
> - const struct pmu_probe_info *info)
> +static int probe_plat_pmu(struct arm_pmu *pmu,
> + const struct pmu_probe_info *info,
> + unsigned int pmuid)
> {
> - int cpu = get_cpu();
> - unsigned int cpuid = read_cpuid_id();
> int ret = -ENODEV;
> + int cpu;
> + int aff_ctr = 0;
> + struct platform_device *pdev = pmu->plat_device;
> + int irq = platform_get_irq(pdev, 0);
>
> - pr_info("probing PMU on CPU %d\n", cpu);
> + if (irq >= 0 && !irq_is_percpu(irq)) {
> + pmu->irq_affinity = kcalloc(pdev->num_resources, sizeof(int),
> + GFP_KERNEL);
> + if (!pmu->irq_affinity)
> + return -ENOMEM;
> + }
> +
> + for_each_possible_cpu(cpu) {
> + unsigned int cpuid = read_specific_cpuid(cpu);
> +
> + if (cpuid == pmuid) {
> + cpumask_set_cpu(cpu, &pmu->supported_cpus);
> + pr_devel("enable pmu on cpu %d\n", cpu);
Please remove the pr_devels that you've added (similarly elsewhere in
the patch).
> + if (pmu->irq_affinity) {
> + pmu->irq_affinity[aff_ctr] = cpu;
> + aff_ctr++;
> + }
> + }
> + }
>
> + pr_debug("probing PMU %X\n", pmuid);
You can also kill this now -- I don't think it's much use.
> + /* find the type of PMU given the CPU */
> for (; info->init != NULL; info++) {
> - if ((cpuid & info->mask) != info->cpuid)
> + if ((pmuid & info->mask) != info->cpuid)
> continue;
> + pr_devel("Found PMU\n");
> ret = info->init(pmu);
> + if (!info->cpuid) {
> + pmu->name = kasprintf(GFP_KERNEL, "%s_0x%x",
> + pmu->name, ARM_PARTNUM(pmuid));
Hmm, I'm not so keen on this. I think we should name the first PMU
"armv8_pmuv3" (i.e. pmu->name) and then any subsequent PMUs should inherit
an index, e.g. "armv8_pmuv3_1". That follows a similar style to uncore
PMUs and also keeps this backwards compatible with what's currently done
with devicetree.
You can create a 'cpumask' file in the sysfs directory that identifies
the cores for the PMU (again, there is precedent for this elsewhere).
Will
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