[PATCH 5/8] arm: arm64: pmu: Assign platform PMU CPU affinity
From: Will Deacon <hidden>
Date: 2016-06-15 13:09:50
Also in:
linux-acpi
On Thu, Jun 09, 2016 at 05:23:30PM -0500, Jeremy Linton wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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