[PATCH 06/14] perf, x86: PEBS infrastructure

Peter Zijlstra
2010-03-04T14:03:36Z

[-- Attachment #1: pebs.patch --]
[-- Type: text/plain, Size: 29662 bytes --]

Implement a simple PEBS model that always takes a single PEBS event at
a time. This is done so that the interaction with the rest of the
system is as expected (freq adjust, period randomization, lbr).

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
---
arch/x86/kernel/cpu/perf_event.c | 223 ++++-------
arch/x86/kernel/cpu/perf_event_intel.c | 152 +-------
arch/x86/kernel/cpu/perf_event_intel_ds.c | 567 ++++++++++++++++++++++++++++++
include/linux/perf_event.h | 3
4 files changed, 682 insertions(+), 263 deletions(-)

Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
===================================================================
--- /dev/null
+++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -0,0 +1,567 @@
+#ifdef CONFIG_CPU_SUP_INTEL
+
+/* The maximal number of PEBS events: */
+#define MAX_PEBS_EVENTS 4
+
+/* The size of a BTS record in bytes: */
+#define BTS_RECORD_SIZE 24
+
+#define BTS_BUFFER_SIZE (PAGE_SIZE << 4)
+#define PEBS_BUFFER_SIZE PAGE_SIZE
+
+/*
+ * pebs_record_32 for p4 and core not supported
+
+struct pebs_record_32 {
+ u32 flags, ip;
+ u32 ax, bc, cx, dx;
+ u32 si, di, bp, sp;
+};
+
+ */
+
+struct pebs_record_core {
+ u64 flags, ip;
+ u64 ax, bx, cx, dx;
+ u64 si, di, bp, sp;
+ u64 r8, r9, r10, r11;
+ u64 r12, r13, r14, r15;
+};
+
+struct pebs_record_nhm {
+ u64 flags, ip;
+ u64 ax, bx, cx, dx;
+ u64 si, di, bp, sp;
+ u64 r8, r9, r10, r11;
+ u64 r12, r13, r14, r15;
+ u64 status, dla, dse, lat;
+};
+
+/*
+ * Bits in the debugctlmsr controlling branch tracing.
+ */
+#define X86_DEBUGCTL_TR (1 << 6)
+#define X86_DEBUGCTL_BTS (1 << 7)
+#define X86_DEBUGCTL_BTINT (1 << 8)
+#define X86_DEBUGCTL_BTS_OFF_OS (1 << 9)
+#define X86_DEBUGCTL_BTS_OFF_USR (1 << 10)
+
+/*
+ * A debug store configuration.
+ *
+ * We only support architectures that use 64bit fields.
+ */
+struct debug_store {
+ u64 bts_buffer_base;
+ u64 bts_index;
+ u64 bts_absolute_maximum;
+ u64 bts_interrupt_threshold;
+ u64 pebs_buffer_base;
+ u64 pebs_index;
+ u64 pebs_absolute_maximum;
+ u64 pebs_interrupt_threshold;
+ u64 pebs_event_reset[MAX_PEBS_EVENTS];
+};
+
+static inline void init_debug_store_on_cpu(int cpu)
+{
+ struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+
+ if (!ds)
+ return;
+
+ wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA,
+ (u32)((u64)(unsigned long)ds),
+ (u32)((u64)(unsigned long)ds >> 32));
+}
+
+static inline void fini_debug_store_on_cpu(int cpu)
+{
+ if (!per_cpu(cpu_hw_events, cpu).ds)
+ return;
+
+ wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
+}
+
+static void release_ds_buffers(void)
+{
+ int cpu;
+
+ if (!x86_pmu.bts && !x86_pmu.pebs)
+ return;
+
+ get_online_cpus();
+
+ for_each_online_cpu(cpu)
+ fini_debug_store_on_cpu(cpu);
+
+ for_each_possible_cpu(cpu) {
+ struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
+
+ if (!ds)
+ continue;
+
+ per_cpu(cpu_hw_events, cpu).ds = NULL;
+
+ kfree((void *)(unsigned long)ds->pebs_buffer_base);
+ kfree((void *)(unsigned long)ds->bts_buffer_base);
+ kfree(ds);
+ }
+
+ put_online_cpus();
+}
+
+static int reserve_ds_buffers(void)
+{
+ int cpu, err = 0;
+
+ if (!x86_pmu.bts && !x86_pmu.pebs)
+ return 0;
+
+ get_online_cpus();
+
+ for_each_possible_cpu(cpu) {
+ struct debug_store *ds;
+ void *buffer;
+ int max, thresh;
+
+ err = -ENOMEM;
+ ds = kzalloc(sizeof(*ds), GFP_KERNEL);
+ if (unlikely(!ds)) {
+ kfree(buffer);
+ break;
+ }
+ per_cpu(cpu_hw_events, cpu).ds = ds;
+
+ if (x86_pmu.bts) {
+ buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
+ if (unlikely(!buffer))
+ break;
+
+ max = BTS_BUFFER_SIZE / BTS_RECORD_SIZE;
+ thresh = max / 16;
+
+ ds->bts_buffer_base = (u64)(unsigned long)buffer;
+ ds->bts_index = ds->bts_buffer_base;
+ ds->bts_absolute_maximum = ds->bts_buffer_base +
+ max * BTS_RECORD_SIZE;
+ ds->bts_interrupt_threshold = ds->bts_absolute_maximum -
+ thresh * BTS_RECORD_SIZE;
+ }
+
+ if (x86_pmu.pebs) {
+ buffer = kzalloc(PEBS_BUFFER_SIZE, GFP_KERNEL);
+ if (unlikely(!buffer))
+ break;
+
+ max = PEBS_BUFFER_SIZE / x86_pmu.pebs_record_size;
+
+ ds->pebs_buffer_base = (u64)(unsigned long)buffer;
+ ds->pebs_index = ds->pebs_buffer_base;
+ ds->pebs_absolute_maximum = ds->pebs_buffer_base +
+ max * x86_pmu.pebs_record_size;
+ /*
+ * Always use single record PEBS
+ */
+ ds->pebs_interrupt_threshold = ds->pebs_buffer_base +
+ x86_pmu.pebs_record_size;
+ }
+
+ err = 0;
+ }
+
+ if (err)
+ release_ds_buffers();
+ else {
+ for_each_online_cpu(cpu)
+ init_debug_store_on_cpu(cpu);
+ }
+
+ put_online_cpus();
+
+ return err;
+}
+
+/*
+ * BTS
+ */
+
+static struct event_constraint bts_constraint =
+ EVENT_CONSTRAINT(0, 1ULL << X86_PMC_IDX_FIXED_BTS, 0);
+
+static void intel_pmu_enable_bts(u64 config)
+{
+ unsigned long debugctlmsr;
+
+ debugctlmsr = get_debugctlmsr();
+
+ debugctlmsr |= X86_DEBUGCTL_TR;
+ debugctlmsr |= X86_DEBUGCTL_BTS;
+ debugctlmsr |= X86_DEBUGCTL_BTINT;
+
+ if (!(config & ARCH_PERFMON_EVENTSEL_OS))
+ debugctlmsr |= X86_DEBUGCTL_BTS_OFF_OS;
+
+ if (!(config & ARCH_PERFMON_EVENTSEL_USR))
+ debugctlmsr |= X86_DEBUGCTL_BTS_OFF_USR;
+
+ update_debugctlmsr(debugctlmsr);
+}
+
+static void intel_pmu_disable_bts(void)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ unsigned long debugctlmsr;
+
+ if (!cpuc->ds)
+ return;
+
+ debugctlmsr = get_debugctlmsr();
+
+ debugctlmsr &=
+ ~(X86_DEBUGCTL_TR | X86_DEBUGCTL_BTS | X86_DEBUGCTL_BTINT |
+ X86_DEBUGCTL_BTS_OFF_OS | X86_DEBUGCTL_BTS_OFF_USR);
+
+ update_debugctlmsr(debugctlmsr);
+}
+
+static void intel_pmu_drain_bts_buffer(void)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct debug_store *ds = cpuc->ds;
+ struct bts_record {
+ u64 from;
+ u64 to;
+ u64 flags;
+ };
+ struct perf_event *event = cpuc->events[X86_PMC_IDX_FIXED_BTS];
+ struct bts_record *at, *top;
+ struct perf_output_handle handle;
+ struct perf_event_header header;
+ struct perf_sample_data data;
+ struct pt_regs regs;
+
+ if (!event)
+ return;
+
+ if (!ds)
+ return;
+
+ at = (struct bts_record *)(unsigned long)ds->bts_buffer_base;
+ top = (struct bts_record *)(unsigned long)ds->bts_index;
+
+ if (top <= at)
+ return;
+
+ ds->bts_index = ds->bts_buffer_base;
+
+ perf_sample_data_init(&data, 0);
+ data.period = event->hw.last_period;
+ regs.ip = 0;
+
+ /*
+ * Prepare a generic sample, i.e. fill in the invariant fields.
+ * We will overwrite the from and to address before we output
+ * the sample.
+ */
+ perf_prepare_sample(&header, &data, event, &regs);
+
+ if (perf_output_begin(&handle, event, header.size * (top - at), 1, 1))
+ return;
+
+ for (; at < top; at++) {
+ data.ip = at->from;
+ data.addr = at->to;
+
+ perf_output_sample(&handle, &header, &data, event);
+ }
+
+ perf_output_end(&handle);
+
+ /* There's new data available. */
+ event->hw.interrupts++;
+ event->pending_kill = POLL_IN;
+}
+
+/*
+ * PEBS
+ */
+
+static struct event_constraint intel_core_pebs_events[] = {
+ PEBS_EVENT_CONSTRAINT(0x00c0, 0x1), /* INSTR_RETIRED.ANY */
+ PEBS_EVENT_CONSTRAINT(0xfec1, 0x1), /* X87_OPS_RETIRED.ANY */
+ PEBS_EVENT_CONSTRAINT(0x00c5, 0x1), /* BR_INST_RETIRED.MISPRED */
+ PEBS_EVENT_CONSTRAINT(0x1fc7, 0x1), /* SIMD_INST_RETURED.ANY */
+ PEBS_EVENT_CONSTRAINT(0x01cb, 0x1), /* MEM_LOAD_RETIRED.L1D_MISS */
+ PEBS_EVENT_CONSTRAINT(0x02cb, 0x1), /* MEM_LOAD_RETIRED.L1D_LINE_MISS */
+ PEBS_EVENT_CONSTRAINT(0x04cb, 0x1), /* MEM_LOAD_RETIRED.L2_MISS */
+ PEBS_EVENT_CONSTRAINT(0x08cb, 0x1), /* MEM_LOAD_RETIRED.L2_LINE_MISS */
+ PEBS_EVENT_CONSTRAINT(0x10cb, 0x1), /* MEM_LOAD_RETIRED.DTLB_MISS */
+ EVENT_CONSTRAINT_END
+};
+
+static struct event_constraint intel_nehalem_pebs_events[] = {
+ PEBS_EVENT_CONSTRAINT(0x00c0, 0xf), /* INSTR_RETIRED.ANY */
+ PEBS_EVENT_CONSTRAINT(0xfec1, 0xf), /* X87_OPS_RETIRED.ANY */
+ PEBS_EVENT_CONSTRAINT(0x00c5, 0xf), /* BR_INST_RETIRED.MISPRED */
+ PEBS_EVENT_CONSTRAINT(0x1fc7, 0xf), /* SIMD_INST_RETURED.ANY */
+ PEBS_EVENT_CONSTRAINT(0x01cb, 0xf), /* MEM_LOAD_RETIRED.L1D_MISS */
+ PEBS_EVENT_CONSTRAINT(0x02cb, 0xf), /* MEM_LOAD_RETIRED.L1D_LINE_MISS */
+ PEBS_EVENT_CONSTRAINT(0x04cb, 0xf), /* MEM_LOAD_RETIRED.L2_MISS */
+ PEBS_EVENT_CONSTRAINT(0x08cb, 0xf), /* MEM_LOAD_RETIRED.L2_LINE_MISS */
+ PEBS_EVENT_CONSTRAINT(0x10cb, 0xf), /* MEM_LOAD_RETIRED.DTLB_MISS */
+ EVENT_CONSTRAINT_END
+};
+
+static struct event_constraint *
+intel_pebs_constraints(struct perf_event *event)
+{
+ struct event_constraint *c;
+
+ if (!event->attr.precise)
+ return NULL;
+
+ if (x86_pmu.pebs_constraints) {
+ for_each_event_constraint(c, x86_pmu.pebs_constraints) {
+ if ((event->hw.config & c->cmask) == c->code)
+ return c;
+ }
+ }
+
+ return &emptyconstraint;
+}
+
+static void intel_pmu_pebs_enable(struct hw_perf_event *hwc)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ u64 val = cpuc->pebs_enabled;
+
+ hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;
+
+ val |= 1ULL << hwc->idx;
+ wrmsrl(MSR_IA32_PEBS_ENABLE, val);
+}
+
+static void intel_pmu_pebs_disable(struct hw_perf_event *hwc)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ u64 val = cpuc->pebs_enabled;
+
+ val &= ~(1ULL << hwc->idx);
+ wrmsrl(MSR_IA32_PEBS_ENABLE, val);
+
+ hwc->config |= ARCH_PERFMON_EVENTSEL_INT;
+}
+
+static void intel_pmu_pebs_enable_all(void)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+ if (cpuc->pebs_enabled)
+ wrmsrl(MSR_IA32_PEBS_ENABLE, cpuc->pebs_enabled);
+}
+
+static void intel_pmu_pebs_disable_all(void)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+
+ if (cpuc->pebs_enabled)
+ wrmsrl(MSR_IA32_PEBS_ENABLE, 0);
+}
+
+static int intel_pmu_save_and_restart(struct perf_event *event);
+static void intel_pmu_disable_event(struct perf_event *event);
+
+static void intel_pmu_drain_pebs_core(struct pt_regs *iregs)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct debug_store *ds = cpuc->ds;
+ struct perf_event *event = cpuc->events[0]; /* PMC0 only */
+ struct pebs_record_core *at, *top;
+ struct perf_sample_data data;
+ struct pt_regs regs;
+ int n;
+
+ if (!event || !ds || !x86_pmu.pebs)
+ return;
+
+ intel_pmu_pebs_disable_all();
+
+ at = (struct pebs_record_core *)(unsigned long)ds->pebs_buffer_base;
+ top = (struct pebs_record_core *)(unsigned long)ds->pebs_index;
+
+ if (top <= at)
+ goto out;
+
+ ds->pebs_index = ds->pebs_buffer_base;
+
+ if (!intel_pmu_save_and_restart(event))
+ goto out;
+
+ perf_sample_data_init(&data, 0);
+ data.period = event->hw.last_period;
+
+ n = top - at;
+
+ /*
+ * Should not happen, we program the threshold at 1 and do not
+ * set a reset value.
+ */
+ if (unlikely(n > 1)) {
+ trace_printk("PEBS: too many events: %d\n", n);
+ at += n-1;
+ }
+
+ /*
+ * We use the interrupt regs as a base because the PEBS record
+ * does not contain a full regs set, specifically it seems to
+ * lack segment descriptors, which get used by things like
+ * user_mode().
+ *
+ * In the simple case fix up only the IP and BP,SP regs, for
+ * PERF_SAMPLE_IP and PERF_SAMPLE_CALLCHAIN to function properly.
+ * A possible PERF_SAMPLE_REGS will have to transfer all regs.
+ */
+ regs = *iregs;
+ regs.ip = at->ip;
+ regs.bp = at->bp;
+ regs.sp = at->sp;
+
+ if (perf_event_overflow(event, 1, &data, &regs))
+ intel_pmu_disable_event(event);
+
+out:
+ intel_pmu_pebs_enable_all();
+}
+
+static void intel_pmu_drain_pebs_nhm(struct pt_regs *iregs)
+{
+ struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
+ struct debug_store *ds = cpuc->ds;
+ struct pebs_record_nhm *at, *top;
+ struct perf_sample_data data;
+ struct perf_event *event = NULL;
+ struct pt_regs regs;
+ int bit, n;
+
+ if (!ds || !x86_pmu.pebs)
+ return;
+
+ intel_pmu_pebs_disable_all();
+
+ at = (struct pebs_record_nhm *)(unsigned long)ds->pebs_buffer_base;
+ top = (struct pebs_record_nhm *)(unsigned long)ds->pebs_index;
+
+ if (top <= at)
+ goto out;
+
+ ds->pebs_index = ds->pebs_buffer_base;
+
+ n = top - at;
+
+ /*
+ * Should not happen, we program the threshold at 1 and do not
+ * set a reset value.
+ */
+ if (unlikely(n > MAX_PEBS_EVENTS))
+ trace_printk("PEBS: too many events: %d\n", n);
+
+ for ( ; at < top; at++) {
+ for_each_bit(bit, (unsigned long *)&at->status, MAX_PEBS_EVENTS) {
+ if (!cpuc->events[bit]->attr.precise)
+ continue;
+
+ if (event)
+ trace_printk("PEBS: status: %Lx\n", at->status);
+
+ event = cpuc->events[bit];
+ }
+
+ if (!event) {
+ trace_printk("PEBS: interrupt, status: %Lx\n",
+ at->status);
+ continue;
+ }
+
+ if (!intel_pmu_save_and_restart(event))
+ continue;
+
+ perf_sample_data_init(&data, 0);
+ data.period = event->hw.last_period;
+
+ /*
+ * See the comment in intel_pmu_drain_pebs_core()
+ */
+ regs = *iregs;
+ regs.ip = at->ip;
+ regs.bp = at->bp;
+ regs.sp = at->sp;
+
+ if (perf_event_overflow(event, 1, &data, &regs))
+ intel_pmu_disable_event(event);
+ }
+out:
+ intel_pmu_pebs_enable_all();
+}
+
+/*
+ * BTS, PEBS probe and setup
+ */
+
+static void intel_ds_init(void)
+{
+ /*
+ * No support for 32bit formats
+ */
+ if (!boot_cpu_has(X86_FEATURE_DTES64))
+ return;
+
+ x86_pmu.bts = boot_cpu_has(X86_FEATURE_BTS);
+ x86_pmu.pebs = boot_cpu_has(X86_FEATURE_PEBS);
+ if (x86_pmu.pebs) {
+ int format = 0;
+
+ if (x86_pmu.version > 1) {
+ u64 capabilities;
+ /*
+ * v2+ has a PEBS format field
+ */
+ rdmsrl(MSR_IA32_PERF_CAPABILITIES, capabilities);
+ format = (capabilities >> 8) & 0xf;
+ }
+
+ switch (format) {
+ case 0:
+ printk(KERN_CONT "PEBS v0, ");
+ x86_pmu.pebs_record_size = sizeof(struct pebs_record_core);
+ x86_pmu.drain_pebs = intel_pmu_drain_pebs_core;
+ x86_pmu.pebs_constraints = intel_core_pebs_events;
+ break;
+
+ case 1:
+ printk(KERN_CONT "PEBS v1, ");
+ x86_pmu.pebs_record_size = sizeof(struct pebs_record_nhm);
+ x86_pmu.drain_pebs = intel_pmu_drain_pebs_nhm;
+ x86_pmu.pebs_constraints = intel_nehalem_pebs_events;
+ break;
+
+ default:
+ printk(KERN_CONT "PEBS unknown format: %d, ", format);
+ x86_pmu.pebs = 0;
+ break;
+ }
+ }
+}
+
+#else /* CONFIG_CPU_SUP_INTEL */
+
+static int reseve_ds_buffers(void)
+{
+ return 0;
+}
+
+static void release_ds_buffers(void)
+{
+}
+
+#endif /* CONFIG_CPU_SUP_INTEL */
Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -31,45 +31,6 @@

static u64 perf_event_mask __read_mostly;

-/* The maximal number of PEBS events: */
-#define MAX_PEBS_EVENTS 4
-
-/* The size of a BTS record in bytes: */
-#define BTS_RECORD_SIZE 24
-
-/* The size of a per-cpu BTS buffer in bytes: */
-#define BTS_BUFFER_SIZE (BTS_RECORD_SIZE * 2048)
-
-/* The BTS overflow threshold in bytes from the end of the buffer: */
-#define BTS_OVFL_TH (BTS_RECORD_SIZE * 128)
-
-
-/*
- * Bits in the debugctlmsr controlling branch tracing.
- */
-#define X86_DEBUGCTL_TR (1 << 6)
-#define X86_DEBUGCTL_BTS (1 << 7)
-#define X86_DEBUGCTL_BTINT (1 << 8)
-#define X86_DEBUGCTL_BTS_OFF_OS (1 << 9)
-#define X86_DEBUGCTL_BTS_OFF_USR (1 << 10)
-
-/*
- * A debug store configuration.
- *
- * We only support architectures that use 64bit fields.
- */
-struct debug_store {
- u64 bts_buffer_base;
- u64 bts_index;
- u64 bts_absolute_maximum;
- u64 bts_interrupt_threshold;
- u64 pebs_buffer_base;
- u64 pebs_index;
- u64 pebs_absolute_maximum;
- u64 pebs_interrupt_threshold;
- u64 pebs_event_reset[MAX_PEBS_EVENTS];
-};
-
struct event_constraint {
union {
unsigned long idxmsk[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
@@ -88,17 +49,29 @@ struct amd_nb {
};

struct cpu_hw_events {
+ /*
+ * Generic x86 PMC bits
+ */
struct perf_event *events[X86_PMC_IDX_MAX]; /* in counter order */
unsigned long active_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
unsigned long interrupts;
int enabled;
- struct debug_store *ds;

int n_events;
int n_added;
int assign[X86_PMC_IDX_MAX]; /* event to counter assignment */
u64 tags[X86_PMC_IDX_MAX];
struct perf_event *event_list[X86_PMC_IDX_MAX]; /* in enabled order */
+
+ /*
+ * Intel DebugStore bits
+ */
+ struct debug_store *ds;
+ u64 pebs_enabled;
+
+ /*
+ * AMD specific bits
+ */
struct amd_nb *amd_nb;
};

@@ -112,12 +85,24 @@ struct cpu_hw_events {
#define EVENT_CONSTRAINT(c, n, m) \
__EVENT_CONSTRAINT(c, n, m, HWEIGHT(n))

+/*
+ * Constraint on the Event code.
+ */
#define INTEL_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVTSEL_MASK)

+/*
+ * Constraint on the Event code + UMask + fixed-mask
+ */
#define FIXED_EVENT_CONSTRAINT(c, n) \
EVENT_CONSTRAINT(c, (1ULL << (32+n)), INTEL_ARCH_FIXED_MASK)

+/*
+ * Constraint on the Event code + UMask
+ */
+#define PEBS_EVENT_CONSTRAINT(c, n) \
+ EVENT_CONSTRAINT(c, n, INTEL_ARCH_EVENT_MASK)
+
#define EVENT_CONSTRAINT_END \
EVENT_CONSTRAINT(0, 0, 0)

@@ -128,6 +113,9 @@ struct cpu_hw_events {
* struct x86_pmu - generic x86 pmu
*/
struct x86_pmu {
+ /*
+ * Generic x86 PMC bits
+ */
const char *name;
int version;
int (*handle_irq)(struct pt_regs *);
@@ -146,10 +134,6 @@ struct x86_pmu {
u64 event_mask;
int apic;
u64 max_period;
- u64 intel_ctrl;
- void (*enable_bts)(u64 config);
- void (*disable_bts)(void);
-
struct event_constraint *
(*get_event_constraints)(struct cpu_hw_events *cpuc,
struct perf_event *event);
@@ -157,6 +141,19 @@ struct x86_pmu {
void (*put_event_constraints)(struct cpu_hw_events *cpuc,
struct perf_event *event);
struct event_constraint *event_constraints;
+
+ /*
+ * Intel Arch Perfmon v2+
+ */
+ u64 intel_ctrl;
+
+ /*
+ * Intel DebugStore bits
+ */
+ int bts, pebs;
+ int pebs_record_size;
+ void (*drain_pebs)(struct pt_regs *regs);
+ struct event_constraint *pebs_constraints;
};

static struct x86_pmu x86_pmu __read_mostly;
@@ -288,110 +285,14 @@ static void release_pmc_hardware(void)
#endif
}

-static inline bool bts_available(void)
-{
- return x86_pmu.enable_bts != NULL;
-}
-
-static inline void init_debug_store_on_cpu(int cpu)
-{
- struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
-
- if (!ds)
- return;
-
- wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA,
- (u32)((u64)(unsigned long)ds),
- (u32)((u64)(unsigned long)ds >> 32));
-}
-
-static inline void fini_debug_store_on_cpu(int cpu)
-{
- if (!per_cpu(cpu_hw_events, cpu).ds)
- return;
-
- wrmsr_on_cpu(cpu, MSR_IA32_DS_AREA, 0, 0);
-}
-
-static void release_bts_hardware(void)
-{
- int cpu;
-
- if (!bts_available())
- return;
-
- get_online_cpus();
-
- for_each_online_cpu(cpu)
- fini_debug_store_on_cpu(cpu);
-
- for_each_possible_cpu(cpu) {
- struct debug_store *ds = per_cpu(cpu_hw_events, cpu).ds;
-
- if (!ds)
- continue;
-
- per_cpu(cpu_hw_events, cpu).ds = NULL;
-
- kfree((void *)(unsigned long)ds->bts_buffer_base);
- kfree(ds);
- }
-
- put_online_cpus();
-}
-
-static int reserve_bts_hardware(void)
-{
- int cpu, err = 0;
-
- if (!bts_available())
- return 0;
-
- get_online_cpus();
-
- for_each_possible_cpu(cpu) {
- struct debug_store *ds;
- void *buffer;
-
- err = -ENOMEM;
- buffer = kzalloc(BTS_BUFFER_SIZE, GFP_KERNEL);
- if (unlikely(!buffer))
- break;
-
- ds = kzalloc(sizeof(*ds), GFP_KERNEL);
- if (unlikely(!ds)) {
- kfree(buffer);
- break;
- }
-
- ds->bts_buffer_base = (u64)(unsigned long)buffer;
- ds->bts_index = ds->bts_buffer_base;
- ds->bts_absolute_maximum =
- ds->bts_buffer_base + BTS_BUFFER_SIZE;
- ds->bts_interrupt_threshold =
- ds->bts_absolute_maximum - BTS_OVFL_TH;
-
- per_cpu(cpu_hw_events, cpu).ds = ds;
- err = 0;
- }
-
- if (err)
- release_bts_hardware();
- else {
- for_each_online_cpu(cpu)
- init_debug_store_on_cpu(cpu);
- }
-
- put_online_cpus();
-
- return err;
-}
+static int reserve_ds_buffers(void);
+static void release_ds_buffers(void);

static void hw_perf_event_destroy(struct perf_event *event)
{
if (atomic_dec_and_mutex_lock(&active_events, &pmc_reserve_mutex)) {
release_pmc_hardware();
- release_bts_hardware();
+ release_ds_buffers();
mutex_unlock(&pmc_reserve_mutex);
}
}
@@ -454,7 +355,7 @@ static int __hw_perf_event_init(struct p
if (!reserve_pmc_hardware())
err = -EBUSY;
else
- err = reserve_bts_hardware();
+ err = reserve_ds_buffers();
}
if (!err)
atomic_inc(&active_events);
@@ -532,7 +433,7 @@ static int __hw_perf_event_init(struct p
if ((attr->config == PERF_COUNT_HW_BRANCH_INSTRUCTIONS) &&
(hwc->sample_period == 1)) {
/* BTS is not supported by this architecture. */
- if (!bts_available())
+ if (!x86_pmu.bts)
return -EOPNOTSUPP;

/* BTS is currently only allowed for user-mode. */
@@ -994,6 +895,7 @@ static void x86_pmu_unthrottle(struct pe
void perf_event_print_debug(void)
{
u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed;
+ u64 pebs;
struct cpu_hw_events *cpuc;
unsigned long flags;
int cpu, idx;
@@ -1011,12 +913,14 @@ void perf_event_print_debug(void)
rdmsrl(MSR_CORE_PERF_GLOBAL_STATUS, status);
rdmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, overflow);
rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR_CTRL, fixed);
+ rdmsrl(MSR_IA32_PEBS_ENABLE, pebs);

pr_info("\n");
pr_info("CPU#%d: ctrl: %016llx\n", cpu, ctrl);
pr_info("CPU#%d: status: %016llx\n", cpu, status);
pr_info("CPU#%d: overflow: %016llx\n", cpu, overflow);
pr_info("CPU#%d: fixed: %016llx\n", cpu, fixed);
+ pr_info("CPU#%d: pebs: %016llx\n", cpu, pebs);
}
pr_info("CPU#%d: active: %016llx\n", cpu, *(u64 *)cpuc->active_mask);

@@ -1334,6 +1238,7 @@ undo:

#include "perf_event_amd.c"
#include "perf_event_p6.c"
+#include "perf_event_intel_ds.c"
#include "perf_event_intel.c"

static void __init pmu_check_apic(void)
@@ -1431,6 +1336,32 @@ static const struct pmu pmu = {
};

/*
+ * validate that we can schedule this event
+ */
+static int validate_event(struct perf_event *event)
+{
+ struct cpu_hw_events *fake_cpuc;
+ struct event_constraint *c;
+ int ret = 0;
+
+ fake_cpuc = kmalloc(sizeof(*fake_cpuc), GFP_KERNEL | __GFP_ZERO);
+ if (!fake_cpuc)
+ return -ENOMEM;
+
+ c = x86_pmu.get_event_constraints(fake_cpuc, event);
+
+ if (!c || !c->weight)
+ ret = -ENOSPC;
+
+ if (x86_pmu.put_event_constraints)
+ x86_pmu.put_event_constraints(fake_cpuc, event);
+
+ kfree(fake_cpuc);
+
+ return ret;
+}
+
+/*
* validate a single event group
*
* validation include:
@@ -1495,6 +1426,8 @@ const struct pmu *hw_perf_event_init(str

if (event->group_leader != event)
err = validate_group(event);
+ else
+ err = validate_event(event);

event->pmu = tmp;
}
Index: linux-2.6/arch/x86/kernel/cpu/perf_event_intel.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event_intel.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event_intel.c
@@ -470,42 +470,6 @@ static u64 intel_pmu_raw_event(u64 hw_ev
return hw_event & CORE_EVNTSEL_MASK;
}

-static void intel_pmu_enable_bts(u64 config)
-{
- unsigned long debugctlmsr;
-
- debugctlmsr = get_debugctlmsr();
-
- debugctlmsr |= X86_DEBUGCTL_TR;
- debugctlmsr |= X86_DEBUGCTL_BTS;
- debugctlmsr |= X86_DEBUGCTL_BTINT;
-
- if (!(config & ARCH_PERFMON_EVENTSEL_OS))
- debugctlmsr |= X86_DEBUGCTL_BTS_OFF_OS;
-
- if (!(config & ARCH_PERFMON_EVENTSEL_USR))
- debugctlmsr |= X86_DEBUGCTL_BTS_OFF_USR;
-
- update_debugctlmsr(debugctlmsr);
-}
-
-static void intel_pmu_disable_bts(void)
-{
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- unsigned long debugctlmsr;
-
- if (!cpuc->ds)
- return;
-
- debugctlmsr = get_debugctlmsr();
-
- debugctlmsr &=
- ~(X86_DEBUGCTL_TR | X86_DEBUGCTL_BTS | X86_DEBUGCTL_BTINT |
- X86_DEBUGCTL_BTS_OFF_OS | X86_DEBUGCTL_BTS_OFF_USR);
-
- update_debugctlmsr(debugctlmsr);
-}
-
static void intel_pmu_disable_all(void)
{
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
@@ -514,6 +478,8 @@ static void intel_pmu_disable_all(void)

if (test_bit(X86_PMC_IDX_FIXED_BTS, cpuc->active_mask))
intel_pmu_disable_bts();
+
+ intel_pmu_pebs_disable_all();
}

static void intel_pmu_enable_all(void)
@@ -531,6 +497,8 @@ static void intel_pmu_enable_all(void)

intel_pmu_enable_bts(event->hw.config);
}
+
+ intel_pmu_pebs_enable_all();
}

static inline u64 intel_pmu_get_status(void)
@@ -547,8 +515,7 @@ static inline void intel_pmu_ack_status(
wrmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, ack);
}

-static inline void
-intel_pmu_disable_fixed(struct hw_perf_event *hwc)
+static void intel_pmu_disable_fixed(struct hw_perf_event *hwc)
{
int idx = hwc->idx - X86_PMC_IDX_FIXED;
u64 ctrl_val, mask;
@@ -560,68 +527,7 @@ intel_pmu_disable_fixed(struct hw_perf_e
(void)checking_wrmsrl(hwc->config_base, ctrl_val);
}

-static void intel_pmu_drain_bts_buffer(void)
-{
- struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
- struct debug_store *ds = cpuc->ds;
- struct bts_record {
- u64 from;
- u64 to;
- u64 flags;
- };
- struct perf_event *event = cpuc->events[X86_PMC_IDX_FIXED_BTS];
- struct bts_record *at, *top;
- struct perf_output_handle handle;
- struct perf_event_header header;
- struct perf_sample_data data;
- struct pt_regs regs;
-
- if (!event)
- return;
-
- if (!ds)
- return;
-
- at = (struct bts_record *)(unsigned long)ds->bts_buffer_base;
- top = (struct bts_record *)(unsigned long)ds->bts_index;
-
- if (top <= at)
- return;
-
- ds->bts_index = ds->bts_buffer_base;
-
- perf_sample_data_init(&data, 0);
-
- data.period = event->hw.last_period;
- regs.ip = 0;
-
- /*
- * Prepare a generic sample, i.e. fill in the invariant fields.
- * We will overwrite the from and to address before we output
- * the sample.
- */
- perf_prepare_sample(&header, &data, event, &regs);
-
- if (perf_output_begin(&handle, event,
- header.size * (top - at), 1, 1))
- return;
-
- for (; at < top; at++) {
- data.ip = at->from;
- data.addr = at->to;
-
- perf_output_sample(&handle, &header, &data, event);
- }
-
- perf_output_end(&handle);
-
- /* There's new data available. */
- event->hw.interrupts++;
- event->pending_kill = POLL_IN;
-}
-
-static inline void
-intel_pmu_disable_event(struct perf_event *event)
+static void intel_pmu_disable_event(struct perf_event *event)
{
struct hw_perf_event *hwc = &event->hw;

@@ -637,10 +543,12 @@ intel_pmu_disable_event(struct perf_even
}

x86_pmu_disable_event(event);
+
+ if (unlikely(event->attr.precise))
+ intel_pmu_pebs_disable(hwc);
}

-static inline void
-intel_pmu_enable_fixed(struct hw_perf_event *hwc)
+static void intel_pmu_enable_fixed(struct hw_perf_event *hwc)
{
int idx = hwc->idx - X86_PMC_IDX_FIXED;
u64 ctrl_val, bits, mask;
@@ -689,6 +597,9 @@ static void intel_pmu_enable_event(struc
return;
}

+ if (unlikely(event->attr.precise))
+ intel_pmu_pebs_enable(hwc);
+
__x86_pmu_enable_event(hwc);
}

@@ -763,10 +674,17 @@ again:

inc_irq_stat(apic_perf_irqs);
ack = status;
+
+ /*
+ * PEBS overflow sets bit 62 in the global status register
+ */
+ if (__test_and_clear_bit(62, (unsigned long *)&status))
+ x86_pmu.drain_pebs(regs);
+
for_each_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
struct perf_event *event = cpuc->events[bit];

- __clear_bit(bit, (unsigned long *) &status);
+ __clear_bit(bit, (unsigned long *)&status);
if (!test_bit(bit, cpuc->active_mask))
continue;

@@ -793,22 +711,18 @@ again:
return 1;
}

-static struct event_constraint bts_constraint =
- EVENT_CONSTRAINT(0, 1ULL << X86_PMC_IDX_FIXED_BTS, 0);
-
static struct event_constraint *
-intel_special_constraints(struct perf_event *event)
+intel_bts_constraints(struct perf_event *event)
{
- unsigned int hw_event;
-
- hw_event = event->hw.config & INTEL_ARCH_EVENT_MASK;
+ struct hw_perf_event *hwc = &event->hw;
+ unsigned int hw_event, bts_event;

- if (unlikely((hw_event ==
- x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS)) &&
- (event->hw.sample_period == 1))) {
+ hw_event = hwc->config & INTEL_ARCH_EVENT_MASK;
+ bts_event = x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS);

+ if (unlikely(hw_event == bts_event && hwc->sample_period == 1))
return &bts_constraint;
- }
+
return NULL;
}

@@ -817,7 +731,11 @@ intel_get_event_constraints(struct cpu_h
{
struct event_constraint *c;

- c = intel_special_constraints(event);
+ c = intel_bts_constraints(event);
+ if (c)
+ return c;
+
+ c = intel_pebs_constraints(event);
if (c)
return c;

@@ -866,8 +784,6 @@ static __initconst struct x86_pmu intel_
* the generic event period:
*/
.max_period = (1ULL << 31) - 1,
- .enable_bts = intel_pmu_enable_bts,
- .disable_bts = intel_pmu_disable_bts,
.get_event_constraints = intel_get_event_constraints
};

@@ -914,6 +830,8 @@ static __init int intel_pmu_init(void)
if (version > 1)
x86_pmu.num_events_fixed = max((int)edx.split.num_events_fixed, 3);

+ intel_ds_init();
+
/*
* Install the hw-cache-events table:
*/
Index: linux-2.6/include/linux/perf_event.h
===================================================================
--- linux-2.6.orig/include/linux/perf_event.h
+++ linux-2.6/include/linux/perf_event.h
@@ -203,8 +203,9 @@ struct perf_event_attr {
enable_on_exec : 1, /* next exec enables */
task : 1, /* trace fork/exit */
watermark : 1, /* wakeup_watermark */
+ precise : 1, /* OoO invariant counter */

- __reserved_1 : 49;
+ __reserved_1 : 48;

union {
__u32 wakeup_events; /* wakeup every n events */

--