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Message-ID: <20130418163315.GA7903@jshin-Toonie>
Date: Thu, 18 Apr 2013 11:33:16 -0500
From: Jacob Shin <jacob.shin@....com>
To: Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC: Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
"H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>, <x86@...nel.org>,
Stephane Eranian <eranian@...gle.com>,
Jiri Olsa <jolsa@...hat.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] perf, amd: support for AMD NB and L2I "uncore"
counters.
On Thu, Apr 18, 2013 at 01:28:54PM +0200, Peter Zijlstra wrote:
> On Mon, 2013-04-15 at 12:21 -0500, Jacob Shin wrote:
> > Add support for AMD Family 15h [and above] northbridge performance
> > counters. MSRs 0xc0010240 ~ 0xc0010247 are shared across all cores
> > that share a common northbridge.
> >
> > Add support for AMD Family 16h L2 performance counters. MSRs
> > 0xc0010230 ~ 0xc0010237 are shared across all cores that share a
> > common L2 cache.
> >
> > We do not enable counter overflow interrupts. Sampling mode and
> > per-thread events are not supported.
>
>
> Nice!
>
> There's one crucial thing missing though.. The Intel uncore driver
> explicitly maps all events of cpus that are of the same uncore to a
> single cpu and migrates the events to another cpu (if any is available)
> when that cpu goes down.
>
> The advantage of keeping all the events on the same cpu is that we
> don't need to consider shared resources between cpus of an uncore
> group.
>
> That way things like event rotation on overcommit also trivially works
> right.
>
> I appreciate the intel uncore driver might be a tad hard to read -- its
> somewhat unwieldy. But it basically sets event->cpu on
> pmu::event_init() to whatever cpu is selected to represent the group,
> and then calls perf_pmu_migrate_context() from a hotplug notifier.
Okay, here is V2 which does that. Thanks again in advance for taking
the time to look it over.
>From d68225744196d8b0d60a1bc33ae9abdbffbd9bc9 Mon Sep 17 00:00:00 2001
From: Jacob Shin <jacob.shin@....com>
Date: Sun, 14 Apr 2013 04:12:42 -0500
Subject: [PATCH 2/2] perf, amd: support for AMD NB and L2I "uncore" counters.
Add support for AMD Family 15h [and above] northbridge performance
counters. MSRs 0xc0010240 ~ 0xc0010247 are shared across all cores
that share a common northbridge.
Add support for AMD Family 16h L2 performance counters. MSRs
0xc0010230 ~ 0xc0010237 are shared across all cores that share a
common L2 cache.
We do not enable counter overflow interrupts. Sampling mode and
per-thread events are not supported.
Signed-off-by: Jacob Shin <jacob.shin@....com>
---
arch/x86/include/asm/cpufeature.h | 2 +
arch/x86/include/uapi/asm/msr-index.h | 4 +
arch/x86/kernel/cpu/Makefile | 2 +-
arch/x86/kernel/cpu/perf_event_amd_uncore.c | 499 +++++++++++++++++++++++++++
4 files changed, 506 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/kernel/cpu/perf_event_amd_uncore.c
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 93fe929..ac10df7 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -168,6 +168,7 @@
#define X86_FEATURE_TOPOEXT (6*32+22) /* topology extensions CPUID leafs */
#define X86_FEATURE_PERFCTR_CORE (6*32+23) /* core performance counter extensions */
#define X86_FEATURE_PERFCTR_NB (6*32+24) /* NB performance counter extensions */
+#define X86_FEATURE_PERFCTR_L2 (6*32+28) /* L2 performance counter extensions */
/*
* Auxiliary flags: Linux defined - For features scattered in various
@@ -311,6 +312,7 @@ extern const char * const x86_power_flags[32];
#define cpu_has_pclmulqdq boot_cpu_has(X86_FEATURE_PCLMULQDQ)
#define cpu_has_perfctr_core boot_cpu_has(X86_FEATURE_PERFCTR_CORE)
#define cpu_has_perfctr_nb boot_cpu_has(X86_FEATURE_PERFCTR_NB)
+#define cpu_has_perfctr_l2 boot_cpu_has(X86_FEATURE_PERFCTR_L2)
#define cpu_has_cx8 boot_cpu_has(X86_FEATURE_CX8)
#define cpu_has_cx16 boot_cpu_has(X86_FEATURE_CX16)
#define cpu_has_eager_fpu boot_cpu_has(X86_FEATURE_EAGER_FPU)
diff --git a/arch/x86/include/uapi/asm/msr-index.h b/arch/x86/include/uapi/asm/msr-index.h
index bf7bb68..b575788 100644
--- a/arch/x86/include/uapi/asm/msr-index.h
+++ b/arch/x86/include/uapi/asm/msr-index.h
@@ -196,6 +196,10 @@
#define MSR_AMD64_IBSBRTARGET 0xc001103b
#define MSR_AMD64_IBS_REG_COUNT_MAX 8 /* includes MSR_AMD64_IBSBRTARGET */
+/* Fam 16h MSRs */
+#define MSR_F16H_L2I_PERF_CTL 0xc0010230
+#define MSR_F16H_L2I_PERF_CTR 0xc0010231
+
/* Fam 15h MSRs */
#define MSR_F15H_PERF_CTL 0xc0010200
#define MSR_F15H_PERF_CTR 0xc0010201
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index a0e067d..0074572 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -31,7 +31,7 @@ obj-$(CONFIG_CPU_SUP_UMC_32) += umc.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o
ifdef CONFIG_PERF_EVENTS
-obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd.o
+obj-$(CONFIG_CPU_SUP_AMD) += perf_event_amd.o perf_event_amd_uncore.o
obj-$(CONFIG_CPU_SUP_INTEL) += perf_event_p6.o perf_event_knc.o perf_event_p4.o
obj-$(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
diff --git a/arch/x86/kernel/cpu/perf_event_amd_uncore.c b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
new file mode 100644
index 0000000..acaeeb1
--- /dev/null
+++ b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
@@ -0,0 +1,499 @@
+/*
+ * Copyright (C) 2013 Advanced Micro Devices, Inc.
+ *
+ * Author: Jacob Shin <jacob.shin@....com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/perf_event.h>
+#include <linux/percpu.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
+
+#include <asm/cpufeature.h>
+#include <asm/perf_event.h>
+#include <asm/msr.h>
+
+#define NUM_COUNTERS_NB 4
+#define NUM_COUNTERS_L2 4
+#define MAX_COUNTERS NUM_COUNTERS_NB
+
+#define RDPMC_BASE_NB 6
+#define RDPMC_BASE_L2 10
+
+#define COUNTER_SHIFT 16
+
+struct amd_uncore {
+ int id;
+ int refcnt;
+ int cpu;
+ int num_counters;
+ int rdpmc_base;
+ u32 msr_base;
+ struct perf_event *events[MAX_COUNTERS];
+ struct amd_uncore *free_when_cpu_online;
+};
+
+static struct amd_uncore * __percpu *amd_uncore_nb;
+static struct amd_uncore * __percpu *amd_uncore_l2;
+
+static struct pmu amd_nb_pmu;
+static struct pmu amd_l2_pmu;
+
+static bool is_nb_event(struct perf_event *event)
+{
+ return event->pmu->type == amd_nb_pmu.type;
+}
+
+static bool is_l2_event(struct perf_event *event)
+{
+ return event->pmu->type == amd_l2_pmu.type;
+}
+
+static struct amd_uncore *event_to_amd_uncore(struct perf_event *event)
+{
+ if (is_nb_event(event) && amd_uncore_nb)
+ return *per_cpu_ptr(amd_uncore_nb, event->cpu);
+ else if (is_l2_event(event) && amd_uncore_l2)
+ return *per_cpu_ptr(amd_uncore_l2, event->cpu);
+
+ return NULL;
+}
+
+static void amd_uncore_read(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ u64 prev, new;
+ s64 delta;
+
+ /*
+ * since we do not enable counter overflow interrupts,
+ * we do not have to worry about prev_count changing on us
+ */
+
+ prev = local64_read(&hwc->prev_count);
+ rdpmcl(hwc->event_base_rdpmc, new);
+ local64_set(&hwc->prev_count, new);
+ delta = (new << COUNTER_SHIFT) - (prev << COUNTER_SHIFT);
+ delta >>= COUNTER_SHIFT;
+ local64_add(delta, &event->count);
+}
+
+static void amd_uncore_start(struct perf_event *event, int flags)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (flags & PERF_EF_RELOAD)
+ wrmsrl(hwc->event_base, (u64)local64_read(&hwc->prev_count));
+
+ hwc->state = 0;
+ wrmsrl(hwc->config_base, (hwc->config | ARCH_PERFMON_EVENTSEL_ENABLE));
+ perf_event_update_userpage(event);
+}
+
+static void amd_uncore_stop(struct perf_event *event, int flags)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ wrmsrl(hwc->config_base, hwc->config);
+ hwc->state |= PERF_HES_STOPPED;
+
+ if ((flags & PERF_EF_UPDATE) && !(hwc->state & PERF_HES_UPTODATE)) {
+ amd_uncore_read(event);
+ hwc->state |= PERF_HES_UPTODATE;
+ }
+}
+
+static int amd_uncore_add(struct perf_event *event, int flags)
+{
+ int i;
+ struct amd_uncore *uncore = event_to_amd_uncore(event);
+ struct hw_perf_event *hwc = &event->hw;
+
+ /* are we already assigned? */
+ if (hwc->idx != -1 && uncore->events[hwc->idx] == event)
+ goto out;
+
+ for (i = 0; i < uncore->num_counters; i++) {
+ if (uncore->events[i] == event) {
+ hwc->idx = i;
+ goto out;
+ }
+ }
+
+ /* if not, take the first available counter */
+ hwc->idx = -1;
+ for (i = 0; i < uncore->num_counters; i++) {
+ if (cmpxchg(&uncore->events[i], NULL, event) == NULL) {
+ hwc->idx = i;
+ break;
+ }
+ }
+
+out:
+ if (hwc->idx == -1)
+ return -EBUSY;
+
+ hwc->config_base = uncore->msr_base + (2 * hwc->idx);
+ hwc->event_base = uncore->msr_base + 1 + (2 * hwc->idx);
+ hwc->event_base_rdpmc = uncore->rdpmc_base + hwc->idx;
+ hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
+
+ if (flags & PERF_EF_START)
+ amd_uncore_start(event, PERF_EF_RELOAD);
+
+ return 0;
+}
+
+static void amd_uncore_del(struct perf_event *event, int flags)
+{
+ int i;
+ struct amd_uncore *uncore = event_to_amd_uncore(event);
+ struct hw_perf_event *hwc = &event->hw;
+
+ amd_uncore_stop(event, PERF_EF_UPDATE);
+
+ for (i = 0; i < uncore->num_counters; i++) {
+ if (cmpxchg(&uncore->events[i], event, NULL) == event)
+ break;
+ }
+
+ hwc->idx = -1;
+}
+
+static int amd_uncore_event_init(struct perf_event *event)
+{
+ struct amd_uncore *uncore;
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (event->attr.type != event->pmu->type)
+ return -ENOENT;
+
+ /*
+ * NB and L2 counters (MSRs) are shared across all cores that share the
+ * same NB / L2 cache. Interrupts can be directed to a single target
+ * core, however, event counts generated by processes running on other
+ * cores cannot be masked out. So we do not support sampling and
+ * per-thread events.
+ */
+ if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
+ return -EINVAL;
+
+ /* NB and L2 counters do not have usr/os/guest/host bits */
+ if (event->attr.exclude_user || event->attr.exclude_kernel ||
+ event->attr.exclude_host || event->attr.exclude_guest)
+ return -EINVAL;
+
+ /* and we do not enable counter overflow interrupts */
+ hwc->config = event->attr.config & AMD64_RAW_EVENT_MASK_NB;
+ hwc->idx = -1;
+
+ if (event->cpu < 0)
+ return -EINVAL;
+
+ uncore = event_to_amd_uncore(event);
+ if (!uncore)
+ return -ENODEV;
+
+ /*
+ * since request can come in to any of the shared cores, we will remap
+ * to a single common cpu.
+ */
+ event->cpu = uncore->cpu;
+
+ return 0;
+}
+
+PMU_FORMAT_ATTR(event, "config:0-7,32-35");
+PMU_FORMAT_ATTR(umask, "config:8-15" );
+
+static struct attribute *amd_uncore_format_attr[] = {
+ &format_attr_event.attr,
+ &format_attr_umask.attr,
+ NULL,
+};
+
+static struct attribute_group amd_uncore_format_group = {
+ .name = "format",
+ .attrs = amd_uncore_format_attr,
+};
+
+static const struct attribute_group *amd_uncore_attr_groups[] = {
+ &amd_uncore_format_group,
+ NULL,
+};
+
+static struct pmu amd_nb_pmu = {
+ .attr_groups = amd_uncore_attr_groups,
+ .name = "amd_nb",
+ .event_init = amd_uncore_event_init,
+ .add = amd_uncore_add,
+ .del = amd_uncore_del,
+ .start = amd_uncore_start,
+ .stop = amd_uncore_stop,
+ .read = amd_uncore_read,
+};
+
+static struct pmu amd_l2_pmu = {
+ .attr_groups = amd_uncore_attr_groups,
+ .name = "amd_l2",
+ .event_init = amd_uncore_event_init,
+ .add = amd_uncore_add,
+ .del = amd_uncore_del,
+ .start = amd_uncore_start,
+ .stop = amd_uncore_stop,
+ .read = amd_uncore_read,
+};
+
+static struct amd_uncore * __cpuinit amd_uncore_alloc(unsigned int cpu)
+{
+ return kzalloc_node(sizeof(struct amd_uncore), GFP_KERNEL,
+ cpu_to_node(cpu));
+}
+
+static void __cpuinit amd_uncore_cpu_up_prepare(unsigned int cpu)
+{
+ struct amd_uncore *uncore;
+
+ if (amd_uncore_nb) {
+ uncore = amd_uncore_alloc(cpu);
+ uncore->cpu = cpu;
+ uncore->num_counters = NUM_COUNTERS_NB;
+ uncore->rdpmc_base = RDPMC_BASE_NB;
+ uncore->msr_base = MSR_F15H_NB_PERF_CTL;
+ *per_cpu_ptr(amd_uncore_nb, cpu) = uncore;
+ }
+
+ if (amd_uncore_l2) {
+ uncore = amd_uncore_alloc(cpu);
+ uncore->cpu = cpu;
+ uncore->num_counters = NUM_COUNTERS_L2;
+ uncore->rdpmc_base = RDPMC_BASE_L2;
+ uncore->msr_base = MSR_F16H_L2I_PERF_CTL;
+ *per_cpu_ptr(amd_uncore_l2, cpu) = uncore;
+ }
+}
+
+static struct amd_uncore *
+__cpuinit amd_uncore_find_online_sibling(struct amd_uncore *this,
+ struct amd_uncore * __percpu *uncores)
+{
+ unsigned int cpu;
+ struct amd_uncore *that;
+
+ for_each_online_cpu(cpu) {
+ that = *per_cpu_ptr(uncores, cpu);
+
+ if (!that)
+ continue;
+
+ if (this == that)
+ continue;
+
+ if (this->id == that->id) {
+ that->free_when_cpu_online = this;
+ this = that;
+ break;
+ }
+ }
+
+ this->refcnt++;
+ return this;
+}
+
+static void __cpuinit amd_uncore_cpu_starting(unsigned int cpu)
+{
+ unsigned int eax, ebx, ecx, edx;
+ struct amd_uncore *uncore;
+
+ if (amd_uncore_nb) {
+ uncore = *per_cpu_ptr(amd_uncore_nb, cpu);
+ cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
+ uncore->id = ecx & 0xff;
+
+ uncore = amd_uncore_find_online_sibling(uncore, amd_uncore_nb);
+ *per_cpu_ptr(amd_uncore_nb, cpu) = uncore;
+ }
+
+ if (amd_uncore_l2) {
+ unsigned int apicid = cpu_data(cpu).apicid;
+ unsigned int nshared;
+
+ uncore = *per_cpu_ptr(amd_uncore_l2, cpu);
+ cpuid_count(0x8000001d, 2, &eax, &ebx, &ecx, &edx);
+ nshared = ((eax >> 14) & 0xfff) + 1;
+ uncore->id = apicid - (apicid % nshared);
+
+ uncore = amd_uncore_find_online_sibling(uncore, amd_uncore_l2);
+ *per_cpu_ptr(amd_uncore_l2, cpu) = uncore;
+ }
+}
+
+static void __cpuinit uncore_online(unsigned int cpu,
+ struct amd_uncore * __percpu *uncores)
+{
+ struct amd_uncore *uncore = *per_cpu_ptr(uncores, cpu);
+
+ if (uncore->free_when_cpu_online) {
+ kfree(uncore->free_when_cpu_online);
+ uncore->free_when_cpu_online = NULL;
+ }
+}
+
+static void __cpuinit amd_uncore_cpu_online(unsigned int cpu)
+{
+ if (amd_uncore_nb)
+ uncore_online(cpu, amd_uncore_nb);
+
+ if (amd_uncore_l2)
+ uncore_online(cpu, amd_uncore_l2);
+}
+
+static void __cpuinit uncore_down_prepare(unsigned int cpu,
+ struct amd_uncore * __percpu *uncores,
+ struct pmu *pmu)
+{
+ unsigned int i;
+ struct amd_uncore *this = *per_cpu_ptr(uncores, cpu);
+
+ if (this->cpu != cpu)
+ return;
+
+ /* this cpu is going down, migrate to a shared sibling if possible */
+ for_each_online_cpu(i) {
+ struct amd_uncore *that = *per_cpu_ptr(uncores, i);
+
+ if (cpu == i)
+ continue;
+
+ if (this == that) {
+ that->cpu = i;
+ perf_pmu_migrate_context(pmu, cpu, i);
+ break;
+ }
+ }
+}
+
+static void __cpuinit amd_uncore_cpu_down_prepare(unsigned int cpu)
+{
+ if (amd_uncore_nb)
+ uncore_down_prepare(cpu, amd_uncore_nb, &amd_nb_pmu);
+
+ if (amd_uncore_l2)
+ uncore_down_prepare(cpu, amd_uncore_l2, &amd_l2_pmu);
+}
+
+static void __cpuinit uncore_dead(unsigned int cpu,
+ struct amd_uncore * __percpu *uncores)
+{
+ struct amd_uncore *uncore = *per_cpu_ptr(uncores, cpu);
+
+ if (!--uncore->refcnt)
+ kfree(uncore);
+ *per_cpu_ptr(amd_uncore_nb, cpu) = NULL;
+}
+
+static void __cpuinit amd_uncore_cpu_dead(unsigned int cpu)
+{
+ if (amd_uncore_nb)
+ uncore_dead(cpu, amd_uncore_nb);
+
+ if (amd_uncore_l2)
+ uncore_dead(cpu, amd_uncore_l2);
+}
+
+static int __cpuinit
+amd_uncore_cpu_notifier(struct notifier_block *self, unsigned long action,
+ void *hcpu)
+{
+ unsigned int cpu = (long)hcpu;
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_UP_PREPARE:
+ amd_uncore_cpu_up_prepare(cpu);
+ break;
+
+ case CPU_STARTING:
+ amd_uncore_cpu_starting(cpu);
+ break;
+
+ case CPU_ONLINE:
+ amd_uncore_cpu_online(cpu);
+ break;
+
+ case CPU_DOWN_PREPARE:
+ amd_uncore_cpu_down_prepare(cpu);
+ break;
+
+ case CPU_UP_CANCELED:
+ case CPU_DEAD:
+ amd_uncore_cpu_dead(cpu);
+ break;
+
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block amd_uncore_cpu_notifier_block __cpuinitdata = {
+ .notifier_call = amd_uncore_cpu_notifier,
+ .priority = CPU_PRI_PERF + 1,
+};
+
+static void __init init_cpu_already_online(void *dummy)
+{
+ unsigned int cpu = smp_processor_id();
+
+ amd_uncore_cpu_up_prepare(cpu);
+ amd_uncore_cpu_starting(cpu);
+ amd_uncore_cpu_online(cpu);
+}
+
+static int __init amd_uncore_init(void)
+{
+ unsigned int cpu;
+ int ret = -ENODEV;
+
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+ return -ENODEV;
+
+ if (!cpu_has_topoext)
+ return -ENODEV;
+
+ if (cpu_has_perfctr_nb) {
+ amd_uncore_nb = alloc_percpu(struct amd_uncore *);
+ perf_pmu_register(&amd_nb_pmu, amd_nb_pmu.name, -1);
+
+ printk(KERN_INFO "perf: AMD NB counters detected\n");
+ ret = 0;
+ }
+
+ if (cpu_has_perfctr_l2) {
+ amd_uncore_l2 = alloc_percpu(struct amd_uncore *);
+ perf_pmu_register(&amd_l2_pmu, amd_l2_pmu.name, -1);
+
+ printk(KERN_INFO "perf: AMD L2I counters detected\n");
+ ret = 0;
+ }
+
+ if (ret)
+ return -ENODEV;
+
+ get_online_cpus();
+ /* init cpus already online before registering for hotplug notifier */
+ for_each_online_cpu(cpu)
+ smp_call_function_single(cpu, init_cpu_already_online, NULL, 1);
+
+ register_cpu_notifier(&amd_uncore_cpu_notifier_block);
+ put_online_cpus();
+
+ return 0;
+}
+device_initcall(amd_uncore_init);
--
1.7.9.5
--
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