Re: [PATCH 4/9] perf: Generic intel uncore support

Yan, Zheng
2012-05-04T07:33:07Z

On 05/04/2012 01:12 AM, Peter Zijlstra wrote:
> On Wed, 2012-05-02 at 10:07 +0800, Yan, Zheng wrote:
>> +static struct intel_uncore_box *
>> +__uncore_pmu_find_box(struct intel_uncore_pmu *pmu, int phyid)
>> +{
>> + struct intel_uncore_box *box;
>> + struct hlist_head *head;
>> + struct hlist_node *node;
>> +
>> + head = &pmu->box_hash[phyid % UNCORE_BOX_HASH_SIZE];
>> + hlist_for_each_entry_rcu(box, node, head, hlist) {
>> + if (box->phy_id == phyid)
>> + return box;
>> + }
>> +
>> + return NULL;
>> +}
>
> I still don't get why something like:
>
> static struct intel_uncore_box *
> pmu_to_box(struct intel_uncore_pmu *pmu, int cpu)
> {
> return per_cpu_ptr(pmu->box, cpu);
> }
>
> doesn't work.
>
> Last time you mumbled something about PCI devices, but afaict those are
> in all respects identical to MSR devices except you talk to them using
> PCI-mmio instead of MSR registers.
>
> In fact, since its all local to the generic code there's nothing
> different between pci/msr already.
>
> So how about something like this:
>
> ---
> Makefile | 4 +-
> perf_event_intel_uncore.c | 92 ++++++++++++++++++----------------------------
> perf_event_intel_uncore.h | 4 +-
> 3 files changed, 42 insertions(+), 58 deletions(-)
>
> --- a/arch/x86/kernel/cpu/Makefile
> +++ b/arch/x86/kernel/cpu/Makefile
> @@ -32,7 +32,9 @@ obj-$(CONFIG_PERF_EVENTS) += perf_event
>
> ifdef CONFIG_PERF_EVENTS
> obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd.o
> -obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_p6.o perf_event_p4.o perf_event_intel_lbr.o perf_event_intel_ds.o perf_event_intel.o perf_event_intel_uncore.o
> +obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_p6.o perf_event_p4.o
> +obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_lbr.o perf_event_intel_ds.o perf_event_intel.o
> +obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_intel_uncore.o
> endif
>
> obj-$(CONFIG_X86_MCE) += mcheck/
> --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
> @@ -116,40 +116,21 @@ struct intel_uncore_box *uncore_alloc_bo
> }
>
> static struct intel_uncore_box *
> -__uncore_pmu_find_box(struct intel_uncore_pmu *pmu, int phyid)
> +uncore_pmu_to_box(struct intel_uncore_pmu *pmu, int cpu)
> {
> - struct intel_uncore_box *box;
> - struct hlist_head *head;
> - struct hlist_node *node;
> -
> - head = &pmu->box_hash[phyid % UNCORE_BOX_HASH_SIZE];
> - hlist_for_each_entry_rcu(box, node, head, hlist) {
> - if (box->phy_id == phyid)
> - return box;
> - }
> -
> - return NULL;
> -}
> -
> -static struct intel_uncore_box *
> -uncore_pmu_find_box(struct intel_uncore_pmu *pmu, int phyid)
> -{
> - struct intel_uncore_box *box;
> -
> - rcu_read_lock();
> - box = __uncore_pmu_find_box(pmu, phyid);
> - rcu_read_unlock();
> -
> - return box;
> + return per_cpu_ptr(pmu->box, cpu);
> }
>
> static void uncore_pmu_add_box(struct intel_uncore_pmu *pmu,
> struct intel_uncore_box *box)
> {
> - struct hlist_head *head;
> + int cpu;
>
> - head = &pmu->box_hash[box->phy_id % UNCORE_BOX_HASH_SIZE];
> - hlist_add_head_rcu(&box->hlist, head);
> + for_each_cpu(cpu) {
> + if (box->phys_id != topology_physical_package_id(cpu))
> + continue;
> + per_cpu_ptr(pmu->box, cpu) = box;
> + }
> }
Thank you for your suggestion. One reason I choose hash table is that I'm uncertain
the system behavior when hot-plug a CPU, the PCI uncore device is probed first or
the CPU data is initialized first? If the PCI device is probed first, I think your
code won't work because topology_physical_package_id may return incorrect id.

Regards
Yan, Zheng

>
> static struct intel_uncore_pmu *uncore_event_to_pmu(struct perf_event *event)
> @@ -163,8 +144,7 @@ static struct intel_uncore_box *uncore_e
> * perf core schedules event on the basis of cpu, uncore events are
> * collected by one of the cpus inside a physical package.
> */
> - int phyid = topology_physical_package_id(smp_processor_id());
> - return uncore_pmu_find_box(uncore_event_to_pmu(event), phyid);
> + return uncore_pmu_to_box(uncore_event_to_pmu(event), smp_processor_id());
> }
>
> static int uncore_collect_events(struct intel_uncore_box *box,
> @@ -478,8 +458,7 @@ int uncore_pmu_event_init(struct perf_ev
> */
> if (event->cpu < 0)
> return -EINVAL;
> - box = uncore_pmu_find_box(pmu,
> - topology_physical_package_id(event->cpu));
> + box = uncore_pmu_to_box(pmu, event->cpu);
> if (!box || box->cpu < 0)
> return -EINVAL;
> event->cpu = box->cpu;
> @@ -541,7 +520,11 @@ static int __init uncore_pmu_register(st
>
> static void __init uncore_type_exit(struct intel_uncore_type *type)
> {
> + int i;
> +
> kfree(type->attr_groups[1]);
> + for (i = 0; i < type->num_boxes; i++)
> + free_percpu(type->pmus[i].box);
> kfree(type->pmus);
> type->attr_groups[1] = NULL;
> type->pmus = NULL;
> @@ -566,9 +549,9 @@ static int __init uncore_type_init(struc
> pmus[i].func_id = -1;
> pmus[i].pmu_idx = i;
> pmus[i].type = type;
> -
> - for (j = 0; j < ARRAY_SIZE(pmus[0].box_hash); j++)
> - INIT_HLIST_HEAD(&pmus[i].box_hash[j]);
> + pmus[i].box = alloc_percpu(struct intel_uncore_box *);
> + if (!pmus[i].box)
> + goto fail_percpu;
> }
>
> if (type->event_descs) {
> @@ -591,6 +574,11 @@ static int __init uncore_type_init(struc
>
> type->pmus = pmus;
> return 0;
> +
> +fail_percpu:
> + for (i = 0; i < type->num_boxes; i++)
> + free_percpu(pmus[i].box);
> +
> fail:
> uncore_type_exit(type);
> return -ENOMEM;
> @@ -617,15 +605,13 @@ static void __cpuinit uncore_cpu_dying(i
> struct intel_uncore_type *type;
> struct intel_uncore_pmu *pmu;
> struct intel_uncore_box *box;
> - int i, j, phyid;
> -
> - phyid = topology_physical_package_id(cpu);
> + int i, j;
>
> for (i = 0; msr_uncores[i]; i++) {
> type = msr_uncores[i];
> for (j = 0; j < type->num_boxes; j++) {
> pmu = &type->pmus[j];
> - box = uncore_pmu_find_box(pmu, phyid);
> + box = uncore_pmu_to_box(pmu, cpu);
> if (box && --box->refcnt == 0) {
> hlist_del_rcu(&box->hlist);
> kfree_rcu(box, rcu_head);
> @@ -639,15 +625,13 @@ static int __cpuinit uncore_cpu_starting
> struct intel_uncore_type *type;
> struct intel_uncore_pmu *pmu;
> struct intel_uncore_box *box;
> - int i, j, phyid;
> -
> - phyid = topology_physical_package_id(cpu);
> + int i, j;
>
> for (i = 0; msr_uncores[i]; i++) {
> type = msr_uncores[i];
> for (j = 0; j < type->num_boxes; j++) {
> pmu = &type->pmus[j];
> - box = uncore_pmu_find_box(pmu, phyid);
> + box = uncore_pmu_to_box(pmu, cpu);
> if (box)
> uncore_box_init(box);
> }
> @@ -660,9 +644,7 @@ static int __cpuinit uncore_cpu_prepare(
> struct intel_uncore_type *type;
> struct intel_uncore_pmu *pmu;
> struct intel_uncore_box *exist, *box;
> - int i, j, phyid;
> -
> - phyid = topology_physical_package_id(cpu);
> + int i, j;
>
> /* allocate the box data structure */
> for (i = 0; msr_uncores[i]; i++) {
> @@ -673,7 +655,7 @@ static int __cpuinit uncore_cpu_prepare(
>
> if (pmu->func_id < 0)
> pmu->func_id = j;
> - exist = uncore_pmu_find_box(pmu, phyid);
> + exist = uncore_pmu_to_box(pmu, cpu);
> if (exist)
> exist->refcnt++;
> if (exist)
> @@ -684,7 +666,7 @@ static int __cpuinit uncore_cpu_prepare(
> return -ENOMEM;
>
> box->pmu = pmu;
> - box->phy_id = phyid;
> + box->phys_id = topology_physical_package_id(cpu);
> uncore_pmu_add_box(pmu, box);
> }
> }
> @@ -696,19 +678,19 @@ static void __cpuinit uncore_event_exit_
> struct intel_uncore_type *type;
> struct intel_uncore_pmu *pmu;
> struct intel_uncore_box *box;
> - int i, j, phyid, target;
> + int i, j, phys_id, target;
>
> /* if exiting cpu is used for collecting uncore events */
> if (!cpumask_test_and_clear_cpu(cpu, &uncore_cpu_mask))
> return;
>
> /* find a new cpu to collect uncore events */
> - phyid = topology_physical_package_id(cpu);
> + phys_id = topology_physical_package_id(cpu);
> target = -1;
> for_each_online_cpu(i) {
> if (i == cpu)
> continue;
> - if (phyid == topology_physical_package_id(i)) {
> + if (phys_id == topology_physical_package_id(i)) {
> target = i;
> break;
> }
> @@ -722,7 +704,7 @@ static void __cpuinit uncore_event_exit_
> type = msr_uncores[i];
> for (j = 0; j < type->num_boxes; j++) {
> pmu = &type->pmus[j];
> - box = uncore_pmu_find_box(pmu, phyid);
> + box = uncore_pmu_to_box(pmu, phys_id);
> WARN_ON_ONCE(box->cpu != cpu);
>
> if (target >= 0) {
> @@ -742,11 +724,11 @@ static void __cpuinit uncore_event_init_
> struct intel_uncore_type *type;
> struct intel_uncore_pmu *pmu;
> struct intel_uncore_box *box;
> - int i, j, phyid;
> + int i, j, phys_id;
>
> - phyid = topology_physical_package_id(cpu);
> + phys_id = topology_physical_package_id(cpu);
> for_each_cpu(i, &uncore_cpu_mask) {
> - if (phyid == topology_physical_package_id(i))
> + if (phys_id == topology_physical_package_id(i))
> return;
> }
>
> @@ -756,7 +738,7 @@ static void __cpuinit uncore_event_init_
> type = msr_uncores[i];
> for (j = 0; j < type->num_boxes; j++) {
> pmu = &type->pmus[j];
> - box = uncore_pmu_find_box(pmu, phyid);
> + box = uncore_pmu_to_box(pmu, cpu);
> WARN_ON_ONCE(box->cpu != -1);
> box->cpu = cpu;
> }
> --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.h
> +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.h
> @@ -59,12 +59,12 @@ struct intel_uncore_pmu {
> int pmu_idx;
> int func_id;
> struct intel_uncore_type *type;
> - struct hlist_head box_hash[UNCORE_BOX_HASH_SIZE];
> + struct intel_uncore_box * __per_cpu box;
> };
>
> struct intel_uncore_box {
> struct hlist_node hlist;
> - int phy_id;
> + int phys_id;
> int refcnt;
> int n_active; /* number of active events */
> int n_events;
>