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authorMaria Dimakopoulou <maria.n.dimakopoulou@gmail.com>2014-11-17 20:06:57 +0100
committerIngo Molnar <mingo@kernel.org>2015-04-02 17:33:11 +0200
commit6f6539cad926f55d5eb6e79d05bbe99f0d54d56d (patch)
tree25b7ddb8abc3d567ddd108c9cc601a22ececd3bb /arch/x86/kernel
parent79cba822443a168c8f7f5b853d9c7225a6d5415e (diff)
perf/x86/intel: Add cross-HT counter exclusion infrastructure
This patch adds a new shared_regs style structure to the per-cpu x86 state (cpuc). It is used to coordinate access between counters which must be used with exclusion across HyperThreads on Intel processors. This new struct is not needed on each PMU, thus is is allocated on demand. Signed-off-by: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com> [peterz: spinlock_t -> raw_spinlock_t] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Stephane Eranian <eranian@google.com> Cc: bp@alien8.de Cc: jolsa@redhat.com Cc: kan.liang@intel.com Link: http://lkml.kernel.org/r/1416251225-17721-6-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/cpu/perf_event.h32
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel.c71
2 files changed, 98 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 24a65057c1c0..f31f90e2d859 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -71,6 +71,7 @@ struct event_constraint {
#define PERF_X86_EVENT_COMMITTED 0x8 /* event passed commit_txn */
#define PERF_X86_EVENT_PEBS_LD_HSW 0x10 /* haswell style datala, load */
#define PERF_X86_EVENT_PEBS_NA_HSW 0x20 /* haswell style datala, unknown */
+#define PERF_X86_EVENT_EXCL 0x40 /* HT exclusivity on counter */
#define PERF_X86_EVENT_RDPMC_ALLOWED 0x40 /* grant rdpmc permission */
@@ -123,6 +124,26 @@ struct intel_shared_regs {
unsigned core_id; /* per-core: core id */
};
+enum intel_excl_state_type {
+ INTEL_EXCL_UNUSED = 0, /* counter is unused */
+ INTEL_EXCL_SHARED = 1, /* counter can be used by both threads */
+ INTEL_EXCL_EXCLUSIVE = 2, /* counter can be used by one thread only */
+};
+
+struct intel_excl_states {
+ enum intel_excl_state_type init_state[X86_PMC_IDX_MAX];
+ enum intel_excl_state_type state[X86_PMC_IDX_MAX];
+};
+
+struct intel_excl_cntrs {
+ raw_spinlock_t lock;
+
+ struct intel_excl_states states[2];
+
+ int refcnt; /* per-core: #HT threads */
+ unsigned core_id; /* per-core: core id */
+};
+
#define MAX_LBR_ENTRIES 16
enum {
@@ -185,6 +206,12 @@ struct cpu_hw_events {
* used on Intel NHM/WSM/SNB
*/
struct intel_shared_regs *shared_regs;
+ /*
+ * manage exclusive counter access between hyperthread
+ */
+ struct event_constraint *constraint_list; /* in enable order */
+ struct intel_excl_cntrs *excl_cntrs;
+ int excl_thread_id; /* 0 or 1 */
/*
* AMD specific bits
@@ -208,6 +235,10 @@ struct cpu_hw_events {
#define EVENT_CONSTRAINT(c, n, m) \
__EVENT_CONSTRAINT(c, n, m, HWEIGHT(n), 0, 0)
+#define INTEL_EXCLEVT_CONSTRAINT(c, n) \
+ __EVENT_CONSTRAINT(c, n, ARCH_PERFMON_EVENTSEL_EVENT, HWEIGHT(n),\
+ 0, PERF_X86_EVENT_EXCL)
+
/*
* The overlap flag marks event constraints with overlapping counter
* masks. This is the case if the counter mask of such an event is not
@@ -566,6 +597,7 @@ do { \
*/
#define PMU_FL_NO_HT_SHARING 0x1 /* no hyper-threading resource sharing */
#define PMU_FL_HAS_RSP_1 0x2 /* has 2 equivalent offcore_rsp regs */
+#define PMU_FL_EXCL_CNTRS 0x4 /* has exclusive counter requirements */
#define EVENT_VAR(_id) event_attr_##_id
#define EVENT_PTR(_id) &event_attr_##_id.attr.attr
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 2dd34b57d3ff..7f54000fd0f1 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -2224,16 +2224,52 @@ struct intel_shared_regs *allocate_shared_regs(int cpu)
return regs;
}
+static struct intel_excl_cntrs *allocate_excl_cntrs(int cpu)
+{
+ struct intel_excl_cntrs *c;
+ int i;
+
+ c = kzalloc_node(sizeof(struct intel_excl_cntrs),
+ GFP_KERNEL, cpu_to_node(cpu));
+ if (c) {
+ raw_spin_lock_init(&c->lock);
+ for (i = 0; i < X86_PMC_IDX_MAX; i++) {
+ c->states[0].state[i] = INTEL_EXCL_UNUSED;
+ c->states[0].init_state[i] = INTEL_EXCL_UNUSED;
+
+ c->states[1].state[i] = INTEL_EXCL_UNUSED;
+ c->states[1].init_state[i] = INTEL_EXCL_UNUSED;
+ }
+ c->core_id = -1;
+ }
+ return c;
+}
+
static int intel_pmu_cpu_prepare(int cpu)
{
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
- if (!(x86_pmu.extra_regs || x86_pmu.lbr_sel_map))
- return NOTIFY_OK;
+ if (x86_pmu.extra_regs || x86_pmu.lbr_sel_map) {
+ cpuc->shared_regs = allocate_shared_regs(cpu);
+ if (!cpuc->shared_regs)
+ return NOTIFY_BAD;
+ }
- cpuc->shared_regs = allocate_shared_regs(cpu);
- if (!cpuc->shared_regs)
- return NOTIFY_BAD;
+ if (x86_pmu.flags & PMU_FL_EXCL_CNTRS) {
+ size_t sz = X86_PMC_IDX_MAX * sizeof(struct event_constraint);
+
+ cpuc->constraint_list = kzalloc(sz, GFP_KERNEL);
+ if (!cpuc->constraint_list)
+ return NOTIFY_BAD;
+
+ cpuc->excl_cntrs = allocate_excl_cntrs(cpu);
+ if (!cpuc->excl_cntrs) {
+ kfree(cpuc->constraint_list);
+ kfree(cpuc->shared_regs);
+ return NOTIFY_BAD;
+ }
+ cpuc->excl_thread_id = 0;
+ }
return NOTIFY_OK;
}
@@ -2274,12 +2310,29 @@ static void intel_pmu_cpu_starting(int cpu)
if (x86_pmu.lbr_sel_map)
cpuc->lbr_sel = &cpuc->shared_regs->regs[EXTRA_REG_LBR];
+
+ if (x86_pmu.flags & PMU_FL_EXCL_CNTRS) {
+ for_each_cpu(i, topology_thread_cpumask(cpu)) {
+ struct intel_excl_cntrs *c;
+
+ c = per_cpu(cpu_hw_events, i).excl_cntrs;
+ if (c && c->core_id == core_id) {
+ cpuc->kfree_on_online[1] = cpuc->excl_cntrs;
+ cpuc->excl_cntrs = c;
+ cpuc->excl_thread_id = 1;
+ break;
+ }
+ }
+ cpuc->excl_cntrs->core_id = core_id;
+ cpuc->excl_cntrs->refcnt++;
+ }
}
static void intel_pmu_cpu_dying(int cpu)
{
struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
struct intel_shared_regs *pc;
+ struct intel_excl_cntrs *c;
pc = cpuc->shared_regs;
if (pc) {
@@ -2287,6 +2340,14 @@ static void intel_pmu_cpu_dying(int cpu)
kfree(pc);
cpuc->shared_regs = NULL;
}
+ c = cpuc->excl_cntrs;
+ if (c) {
+ if (c->core_id == -1 || --c->refcnt == 0)
+ kfree(c);
+ cpuc->excl_cntrs = NULL;
+ kfree(cpuc->constraint_list);
+ cpuc->constraint_list = NULL;
+ }
fini_debug_store_on_cpu(cpu);
}