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Message-ID: <1b3cb8a6-1eb0-120a-3382-55abe7918612@linux.intel.com>
Date: Fri, 13 Mar 2020 11:25:31 -0400
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: roman.sudarikov@...ux.intel.com, peterz@...radead.org,
mingo@...hat.com, acme@...nel.org, mark.rutland@....com,
alexander.shishkin@...ux.intel.com, jolsa@...hat.com,
namhyung@...nel.org, linux-kernel@...r.kernel.org,
eranian@...gle.com, bgregg@...flix.com, ak@...ux.intel.com
Cc: alexander.antonov@...el.com
Subject: Re: [PATCH v7 3/3] perf x86: Exposing an Uncore unit to PMON for Intel Xeon® server platform
On 3/3/2020 8:54 AM, roman.sudarikov@...ux.intel.com wrote:
> From: Roman Sudarikov <roman.sudarikov@...ux.intel.com>
>
> Current version supports a server line starting Intel® Xeon® Processor
> Scalable Family and introduces mapping for IIO Uncore units only.
> Other units can be added on demand.
>
> IIO stack to PMON mapping is exposed through:
> /sys/devices/uncore_iio_<pmu_idx>/dieX
> where dieX is file which holds "Segment:Root Bus" for PCIe root port,
> which can be monitored by that IIO PMON block.
>
> Details are explained in Documentation/ABI/testing/sysfs-devices-mapping
>
> Co-developed-by: Alexander Antonov <alexander.antonov@...el.com>
> Signed-off-by: Alexander Antonov <alexander.antonov@...el.com>
> Signed-off-by: Roman Sudarikov <roman.sudarikov@...ux.intel.com>
> ---
> .../ABI/testing/sysfs-devices-mapping | 33 +++
> arch/x86/events/intel/uncore.h | 9 +
> arch/x86/events/intel/uncore_snbep.c | 193 ++++++++++++++++++
> 3 files changed, 235 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-devices-mapping
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-mapping b/Documentation/ABI/testing/sysfs-devices-mapping
> new file mode 100644
> index 000000000000..16f4e900be7b
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-mapping
> @@ -0,0 +1,33 @@
> +What: /sys/devices/uncore_iio_x/dieX
> +Date: February 2020
> +Contact: Roman Sudarikov <roman.sudarikov@...ux.intel.com>
> +Description:
> + Each IIO stack (PCIe root port) has its own IIO PMON block, so
> + each dieX file (where X is die number) holds "Segment:Root Bus"
> + for PCIe root port, which can be monitored by that IIO PMON
> + block.
> + For example, on 4-die Xeon platform with up to 6 IIO stacks per
> + die and, therefore, 6 IIO PMON blocks per die, the mapping of
> + IIO PMON block 0 exposes as the following:
> +
> + $ ls /sys/devices/uncore_iio_0/die*
> + -r--r--r-- /sys/devices/uncore_iio_0/die0
> + -r--r--r-- /sys/devices/uncore_iio_0/die1
> + -r--r--r-- /sys/devices/uncore_iio_0/die2
> + -r--r--r-- /sys/devices/uncore_iio_0/die3
> +
> + $ tail /sys/devices/uncore_iio_0/die*
> + ==> /sys/devices/uncore_iio_0/die0 <==
> + 0000:00
> + ==> /sys/devices/uncore_iio_0/die1 <==
> + 0000:40
> + ==> /sys/devices/uncore_iio_0/die2 <==
> + 0000:80
> + ==> /sys/devices/uncore_iio_0/die3 <==
> + 0000:c0
> +
> + Which means:
> + IIO PMU 0 on die 0 belongs to PCI RP on bus 0x00, domain 0x0000
> + IIO PMU 0 on die 1 belongs to PCI RP on bus 0x40, domain 0x0000
> + IIO PMU 0 on die 2 belongs to PCI RP on bus 0x80, domain 0x0000
> + IIO PMU 0 on die 3 belongs to PCI RP on bus 0xc0, domain 0x0000
> \ No newline at end of file
> diff --git a/arch/x86/events/intel/uncore.h b/arch/x86/events/intel/uncore.h
> index c1da2b8218cd..eb93b8676f34 100644
> --- a/arch/x86/events/intel/uncore.h
> +++ b/arch/x86/events/intel/uncore.h
> @@ -174,6 +174,15 @@ int uncore_pcibus_to_physid(struct pci_bus *bus);
> ssize_t uncore_event_show(struct kobject *kobj,
> struct kobj_attribute *attr, char *buf);
>
> +static inline struct intel_uncore_pmu *dev_to_uncore_pmu(struct device *dev)
> +{
> + return container_of(dev_get_drvdata(dev), struct intel_uncore_pmu, pmu);
> +}
> +
> +#define to_device_attribute(n) container_of(n, struct device_attribute, attr)
> +#define to_dev_ext_attribute(n) container_of(n, struct dev_ext_attribute, attr)
> +#define attr_to_ext_attr(n) to_dev_ext_attribute(to_device_attribute(n))
> +
> extern int __uncore_max_dies;
> #define uncore_max_dies() (__uncore_max_dies)
>
> diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
> index ad20220af303..5e15425c5133 100644
> --- a/arch/x86/events/intel/uncore_snbep.c
> +++ b/arch/x86/events/intel/uncore_snbep.c
> @@ -273,6 +273,30 @@
> #define SKX_CPUNODEID 0xc0
> #define SKX_GIDNIDMAP 0xd4
>
> +/*
> + * The CPU_BUS_NUMBER MSR returns the values of the respective CPUBUSNO CSR
> + * that BIOS programmed. MSR has package scope.
> + * | Bit | Default | Description
> + * | [63] | 00h | VALID - When set, indicates the CPU bus
> + * numbers have been initialized. (RO)
> + * |[62:48]| --- | Reserved
> + * |[47:40]| 00h | BUS_NUM_5 — Return the bus number BIOS assigned
> + * CPUBUSNO(5). (RO)
> + * |[39:32]| 00h | BUS_NUM_4 — Return the bus number BIOS assigned
> + * CPUBUSNO(4). (RO)
> + * |[31:24]| 00h | BUS_NUM_3 — Return the bus number BIOS assigned
> + * CPUBUSNO(3). (RO)
> + * |[23:16]| 00h | BUS_NUM_2 — Return the bus number BIOS assigned
> + * CPUBUSNO(2). (RO)
> + * |[15:8] | 00h | BUS_NUM_1 — Return the bus number BIOS assigned
> + * CPUBUSNO(1). (RO)
> + * | [7:0] | 00h | BUS_NUM_0 — Return the bus number BIOS assigned
> + * CPUBUSNO(0). (RO)
> + */
> +#define SKX_MSR_CPU_BUS_NUMBER 0x300
> +#define SKX_MSR_CPU_BUS_VALID_BIT (1ULL << 63)
> +#define BUS_NUM_STRIDE 8
> +
> /* SKX CHA */
> #define SKX_CHA_MSR_PMON_BOX_FILTER_TID (0x1ffULL << 0)
> #define SKX_CHA_MSR_PMON_BOX_FILTER_LINK (0xfULL << 9)
> @@ -3575,6 +3599,172 @@ static struct intel_uncore_ops skx_uncore_iio_ops = {
> .read_counter = uncore_msr_read_counter,
> };
>
> +static inline u8 skx_iio_stack(struct intel_uncore_pmu *pmu, int die)
> +{
> + return pmu->type->topology[die] >> (pmu->pmu_idx * BUS_NUM_STRIDE);
> +}
> +
> +static umode_t
> +skx_iio_mapping_visible(struct kobject *kobj, struct attribute *attr, int die)
> +{
> + struct intel_uncore_pmu *pmu = dev_to_uncore_pmu(kobj_to_dev(kobj));
> +
> + // Root bus 0x00 is valid only for die 0 AND pmu_idx = 0.
Could you please use /**/ for the comments?
> + return (!skx_iio_stack(pmu, die) && pmu->pmu_idx) ? 0 : attr->mode;
> +}
> +
> +static ssize_t skx_iio_mapping_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct pci_bus *bus = pci_find_next_bus(NULL);
> + struct intel_uncore_pmu *uncore_pmu = dev_to_uncore_pmu(dev);
> + struct dev_ext_attribute *ea = to_dev_ext_attribute(attr);
> + long die = (long)ea->var;
> +
> + /*
> + * Current implementation is for single segment configuration hence it's
> + * safe to take the segment value from the first available root bus.
> + */
> + return sprintf(buf, "%04x:%02x\n", pci_domain_nr(bus),
> + skx_iio_stack(uncore_pmu, die));
> +}
> +
> +static int skx_msr_cpu_bus_read(int cpu, u64 *topology)
> +{
> + u64 msr_value;
> +
> + if (rdmsrl_on_cpu(cpu, SKX_MSR_CPU_BUS_NUMBER, &msr_value) ||
> + !(msr_value & SKX_MSR_CPU_BUS_VALID_BIT))
> + return -ENXIO;
> +
> + *topology = msr_value;
> +
> + return 0;
> +}
> +
> +static int die_to_cpu(int die)
> +{
> + int res = 0, cpu, current_die;
> + /*
> + * Using cpus_read_lock() to ensure cpu is not going down between
> + * looking at cpu_online_mask.
> + */
> + cpus_read_lock();
> + for_each_online_cpu(cpu) {
> + current_die = topology_logical_die_id(cpu);
> + if (current_die == die) {
> + res = cpu;
> + break;
> + }
> + }
> + cpus_read_unlock();
> + return res;
> +}
> +
> +static int skx_iio_get_topology(struct intel_uncore_type *type)
> +{
> + int i, ret;
> + struct pci_bus *bus = NULL;
> +
> + /*
> + * Verified single-segment environments only; disabled for multiple
> + * segment topologies for now except VMD domains.
> + * VMD domains start at 0x10000 to not clash with ACPI _SEG domains.
> + */
> + while ((bus = pci_find_next_bus(bus))
> + && (!pci_domain_nr(bus) || pci_domain_nr(bus) > 0xffff))
> + ;
> + if (bus)
> + return -EPERM;
> +
> + type->topology = kcalloc(uncore_max_dies(), sizeof(u64), GFP_KERNEL);
> + if (!type->topology)
> + return -ENOMEM;
> +
> + for (i = 0; i < uncore_max_dies(); i++) {
> + ret = skx_msr_cpu_bus_read(die_to_cpu(i), &type->topology[i]);
> + if (ret) {
> + kfree(type->topology);
> + type->topology = NULL;
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static struct attribute_group skx_iio_mapping_group = {
> + .is_visible = skx_iio_mapping_visible,
> +};
> +
> +const static struct attribute_group *skx_iio_attr_update[] = {
> + &skx_iio_mapping_group,
> + NULL,
> +};
> +
> +static int skx_iio_set_mapping(struct intel_uncore_type *type)
> +{
> + char buf[64];
> + int ret;
> + long die = -1;
> + struct attribute **attrs = NULL;
> + struct dev_ext_attribute *eas = NULL;
> +
> + ret = skx_iio_get_topology(type);
> + if (ret)
> + return ret;
> +
> + // One more for NULL.
> + attrs = kzalloc((uncore_max_dies() + 1) * sizeof(*attrs), GFP_KERNEL);
> + if (!attrs) {
> + kfree(type->topology);
> + return -ENOMEM;
Please use goto here as well to avoid the duplicate kfree.
Only some minor comments. The rest of codes look good to me.
Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
Thanks,
Kan
> + }
> +
> + eas = kzalloc(sizeof(*eas) * uncore_max_dies(), GFP_KERNEL);
> + if (!eas)
> + goto err;
> +
> + for (die = 0; die < uncore_max_dies(); die++) {
> + sprintf(buf, "die%ld", die);
> + sysfs_attr_init(&eas[die].attr.attr);
> + eas[die].attr.attr.name = kstrdup(buf, GFP_KERNEL);
> + if (!eas[die].attr.attr.name)
> + goto err;
> + eas[die].attr.attr.mode = 0444;
> + eas[die].attr.show = skx_iio_mapping_show;
> + eas[die].attr.store = NULL;
> + eas[die].var = (void *)die;
> + attrs[die] = &eas[die].attr.attr;
> + }
> + skx_iio_mapping_group.attrs = attrs;
> +
> + return 0;
> +err:
> + for (; die >= 0; die--)
> + kfree(eas[die].attr.attr.name);
> + kfree(eas);
> + kfree(attrs);
> + kfree(type->topology);
> + type->attr_update = NULL;
> + return -ENOMEM;
> +}
> +
> +static void skx_iio_cleanup_mapping(struct intel_uncore_type *type)
> +{
> + struct attribute **attr = skx_iio_mapping_group.attrs;
> +
> + if (!attr)
> + return;
> +
> + for (; *attr; attr++)
> + kfree((*attr)->name);
> + kfree(attr_to_ext_attr(*skx_iio_mapping_group.attrs));
> + kfree(skx_iio_mapping_group.attrs);
> + skx_iio_mapping_group.attrs = NULL;
> + kfree(type->topology);
> +}
> +
> static struct intel_uncore_type skx_uncore_iio = {
> .name = "iio",
> .num_counters = 4,
> @@ -3589,6 +3779,9 @@ static struct intel_uncore_type skx_uncore_iio = {
> .constraints = skx_uncore_iio_constraints,
> .ops = &skx_uncore_iio_ops,
> .format_group = &skx_uncore_iio_format_group,
> + .attr_update = skx_iio_attr_update,
> + .set_mapping = skx_iio_set_mapping,
> + .cleanup_mapping = skx_iio_cleanup_mapping,
> };
>
> enum perf_uncore_iio_freerunning_type_id {
>
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