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Subject[RFC][PATCH 09/11] perf_counter: revamp syscall input ABI
The hardware/software classification in hw_event->type became a little strained
due to the addition of tracepoint tracing.

Instead split up the field and provide a type field to explicitly specify the
counter type, while using the event_id field to specify which event to use.

Raw counters still work as before, only the raw config now goes into raw_event.

Updated userspace at:
http://programming.kicks-ass.net/misc/perf_counter/

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
arch/powerpc/kernel/perf_counter.c | 2
arch/x86/kernel/cpu/perf_counter.c | 8 +--
include/linux/perf_counter.h | 83 ++++++++++++++++++++++---------------
kernel/perf_counter.c | 81 +++++++++++++++++++++---------------
4 files changed, 104 insertions(+), 70 deletions(-)
Index: linux-2.6/arch/powerpc/kernel/perf_counter.c
===================================================================
--- linux-2.6.orig/arch/powerpc/kernel/perf_counter.c
+++ linux-2.6/arch/powerpc/kernel/perf_counter.c
@@ -693,7 +693,7 @@ static void perf_handle_group(struct per
list_for_each_entry(sub, &leader->sibling_list, list_entry) {
if (sub != counter)
sub->hw_ops->read(sub);
- perf_store_irq_data(counter, sub->hw_event.type);
+ perf_store_irq_data(counter, sub->hw_event.raw_event);
perf_store_irq_data(counter, atomic64_read(&sub->count));
}
}
Index: linux-2.6/arch/x86/kernel/cpu/perf_counter.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_counter.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_counter.c
@@ -216,14 +216,14 @@ static int __hw_perf_counter_init(struct
* Raw event type provide the config in the event structure
*/
if (hw_event->raw) {
- hwc->config |= pmc_ops->raw_event(hw_event->type);
+ hwc->config |= pmc_ops->raw_event(hw_event->raw_event);
} else {
- if (hw_event->type >= pmc_ops->max_events)
+ if (hw_event->event_id >= pmc_ops->max_events)
return -EINVAL;
/*
* The generic map:
*/
- hwc->config |= pmc_ops->event_map(hw_event->type);
+ hwc->config |= pmc_ops->event_map(hw_event->event_id);
}
counter->wakeup_pending = 0;

@@ -713,7 +713,7 @@ perf_handle_group(struct perf_counter *s
list_for_each_entry(counter, &group_leader->sibling_list, list_entry) {

x86_perf_counter_update(counter, &counter->hw, counter->hw.idx);
- perf_store_irq_data(sibling, counter->hw_event.type);
+ perf_store_irq_data(sibling, counter->hw_event.raw_event);
perf_store_irq_data(sibling, atomic64_read(&counter->count));
}
}
Index: linux-2.6/include/linux/perf_counter.h
===================================================================
--- linux-2.6.orig/include/linux/perf_counter.h
+++ linux-2.6/include/linux/perf_counter.h
@@ -21,56 +21,72 @@
*/

/*
- * Generalized performance counter event types, used by the hw_event.type
+ * hw_event.type
+ */
+enum perf_event_types {
+ PERF_TYPE_HARDWARE = 0,
+ PERF_TYPE_SOFTWARE = 1,
+ PERF_TYPE_TRACEPOINT = 2,
+};
+
+/*
+ * Generalized performance counter event types, used by the hw_event.event_id
* parameter of the sys_perf_counter_open() syscall:
*/
-enum hw_event_types {
+enum hw_event_ids {
/*
* Common hardware events, generalized by the kernel:
*/
- PERF_COUNT_CPU_CYCLES = 0,
- PERF_COUNT_INSTRUCTIONS = 1,
- PERF_COUNT_CACHE_REFERENCES = 2,
- PERF_COUNT_CACHE_MISSES = 3,
- PERF_COUNT_BRANCH_INSTRUCTIONS = 4,
- PERF_COUNT_BRANCH_MISSES = 5,
- PERF_COUNT_BUS_CYCLES = 6,
-
- PERF_HW_EVENTS_MAX = 7,
+ PERF_COUNT_CPU_CYCLES = 0,
+ PERF_COUNT_INSTRUCTIONS = 1,
+ PERF_COUNT_CACHE_REFERENCES = 2,
+ PERF_COUNT_CACHE_MISSES = 3,
+ PERF_COUNT_BRANCH_INSTRUCTIONS = 4,
+ PERF_COUNT_BRANCH_MISSES = 5,
+ PERF_COUNT_BUS_CYCLES = 6,

- /*
- * Special "software" counters provided by the kernel, even if
- * the hardware does not support performance counters. These
- * counters measure various physical and sw events of the
- * kernel (and allow the profiling of them as well):
- */
- PERF_COUNT_CPU_CLOCK = -1,
- PERF_COUNT_TASK_CLOCK = -2,
- PERF_COUNT_PAGE_FAULTS = -3,
- PERF_COUNT_CONTEXT_SWITCHES = -4,
- PERF_COUNT_CPU_MIGRATIONS = -5,
- PERF_COUNT_PAGE_FAULTS_MIN = -6,
- PERF_COUNT_PAGE_FAULTS_MAJ = -7,
+ PERF_HW_EVENTS_MAX = 7,
+};

- PERF_SW_EVENTS_MIN = -8,
+/*
+ * Special "software" counters provided by the kernel, even if the hardware
+ * does not support performance counters. These counters measure various
+ * physical and sw events of the kernel (and allow the profiling of them as
+ * well):
+ */
+enum sw_event_ids {
+ PERF_COUNT_CPU_CLOCK = 0,
+ PERF_COUNT_TASK_CLOCK = 1,
+ PERF_COUNT_PAGE_FAULTS = 2,
+ PERF_COUNT_CONTEXT_SWITCHES = 3,
+ PERF_COUNT_CPU_MIGRATIONS = 4,
+ PERF_COUNT_PAGE_FAULTS_MIN = 5,
+ PERF_COUNT_PAGE_FAULTS_MAJ = 6,

- PERF_TP_EVENTS_MIN = -65536
+ PERF_SW_EVENTS_MAX = 7,
};

/*
* IRQ-notification data record type:
*/
enum perf_counter_record_type {
- PERF_RECORD_SIMPLE = 0,
- PERF_RECORD_IRQ = 1,
- PERF_RECORD_GROUP = 2,
+ PERF_RECORD_SIMPLE = 0,
+ PERF_RECORD_IRQ = 1,
+ PERF_RECORD_GROUP = 2,
};

/*
* Hardware event to monitor via a performance monitoring counter:
*/
struct perf_counter_hw_event {
- __s64 type;
+ union {
+ __u64 raw_event;
+ struct {
+ __u64 event_id : 32,
+ type : 8,
+ __reserved_0 : 24;
+ };
+ };

__u64 irq_period;
__u64 record_type;
@@ -298,10 +314,11 @@ extern int hw_perf_group_sched_in(struct
*/
static inline int is_software_counter(struct perf_counter *counter)
{
- return !counter->hw_event.raw && counter->hw_event.type < 0;
+ return !counter->hw_event.raw &&
+ counter->hw_event.type != PERF_TYPE_HARDWARE;
}

-extern void perf_swcounter_event(enum hw_event_types, u64, int, struct pt_regs *);
+extern void perf_swcounter_event(u32, u64, int, struct pt_regs *);

#else
static inline void
@@ -320,7 +337,7 @@ static inline u64 hw_perf_save_disable(v
static inline int perf_counter_task_disable(void) { return -EINVAL; }
static inline int perf_counter_task_enable(void) { return -EINVAL; }

-static inline void perf_swcounter_event(enum hw_event_types event, u64 nr,
+static inline void perf_swcounter_event(u32 event, u64 nr,
int nmi, struct pt_regs *regs) { }
#endif

Index: linux-2.6/kernel/perf_counter.c
===================================================================
--- linux-2.6.orig/kernel/perf_counter.c
+++ linux-2.6/kernel/perf_counter.c
@@ -1395,12 +1395,6 @@ static void perf_swcounter_set_period(st
atomic64_set(&hwc->count, -left);
}

-static void perf_swcounter_save_and_restart(struct perf_counter *counter)
-{
- perf_swcounter_update(counter);
- perf_swcounter_set_period(counter);
-}
-
static void perf_swcounter_store_irq(struct perf_counter *counter, u64 data)
{
struct perf_data *irqdata = counter->irqdata;
@@ -1421,7 +1415,7 @@ static void perf_swcounter_handle_group(

list_for_each_entry(counter, &group_leader->sibling_list, list_entry) {
counter->hw_ops->read(counter);
- perf_swcounter_store_irq(sibling, counter->hw_event.type);
+ perf_swcounter_store_irq(sibling, counter->hw_event.raw_event);
perf_swcounter_store_irq(sibling, atomic64_read(&counter->count));
}
}
@@ -1477,13 +1471,14 @@ static enum hrtimer_restart perf_swcount
static void perf_swcounter_overflow(struct perf_counter *counter,
int nmi, struct pt_regs *regs)
{
- perf_swcounter_save_and_restart(counter);
+ perf_swcounter_update(counter);
+ perf_swcounter_set_period(counter);
perf_swcounter_interrupt(counter, nmi, regs);
}

static int perf_swcounter_match(struct perf_counter *counter,
- enum hw_event_types event,
- struct pt_regs *regs)
+ enum perf_event_types type,
+ u32 event, struct pt_regs *regs)
{
if (counter->state != PERF_COUNTER_STATE_ACTIVE)
return 0;
@@ -1491,7 +1486,10 @@ static int perf_swcounter_match(struct p
if (counter->hw_event.raw)
return 0;

- if (counter->hw_event.type != event)
+ if (counter->hw_event.type != type)
+ return 0;
+
+ if (counter->hw_event.event_id != event)
return 0;

if (counter->hw_event.exclude_user && user_mode(regs))
@@ -1512,8 +1510,8 @@ static void perf_swcounter_add(struct pe
}

static void perf_swcounter_ctx_event(struct perf_counter_context *ctx,
- enum hw_event_types event, u64 nr,
- int nmi, struct pt_regs *regs)
+ enum perf_event_types type, u32 event,
+ u64 nr, int nmi, struct pt_regs *regs)
{
struct perf_counter *counter;

@@ -1522,24 +1520,31 @@ static void perf_swcounter_ctx_event(str

rcu_read_lock();
list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
- if (perf_swcounter_match(counter, event, regs))
+ if (perf_swcounter_match(counter, type, event, regs))
perf_swcounter_add(counter, nr, nmi, regs);
}
rcu_read_unlock();
}

-void perf_swcounter_event(enum hw_event_types event, u64 nr,
- int nmi, struct pt_regs *regs)
+static void __perf_swcounter_event(enum perf_event_types type, u32 event,
+ u64 nr, int nmi, struct pt_regs *regs)
{
struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context);

- perf_swcounter_ctx_event(&cpuctx->ctx, event, nr, nmi, regs);
- if (cpuctx->task_ctx)
- perf_swcounter_ctx_event(cpuctx->task_ctx, event, nr, nmi, regs);
+ perf_swcounter_ctx_event(&cpuctx->ctx, type, event, nr, nmi, regs);
+ if (cpuctx->task_ctx) {
+ perf_swcounter_ctx_event(cpuctx->task_ctx, type, event,
+ nr, nmi, regs);
+ }

put_cpu_var(perf_cpu_context);
}

+void perf_swcounter_event(u32 event, u64 nr, int nmi, struct pt_regs *regs)
+{
+ __perf_swcounter_event(PERF_TYPE_SOFTWARE, event, nr, nmi, regs);
+}
+
static void perf_swcounter_read(struct perf_counter *counter)
{
perf_swcounter_update(counter);
@@ -1733,8 +1738,12 @@ static const struct hw_perf_counter_ops
#ifdef CONFIG_EVENT_PROFILE
void perf_tpcounter_event(int event_id)
{
- perf_swcounter_event(PERF_TP_EVENTS_MIN + event_id, 1, 1,
- task_pt_regs(current));
+ struct pt_regs *regs = get_irq_regs();
+
+ if (!regs)
+ regs = task_pt_regs(current);
+
+ __perf_swcounter_event(PERF_TYPE_TRACEPOINT, event_id, 1, 1, regs);
}

extern int ftrace_profile_enable(int);
@@ -1742,15 +1751,13 @@ extern void ftrace_profile_disable(int);

static void tp_perf_counter_destroy(struct perf_counter *counter)
{
- int event_id = counter->hw_event.type - PERF_TP_EVENTS_MIN;
-
- ftrace_profile_disable(event_id);
+ ftrace_profile_disable(counter->hw_event.event_id);
}

static const struct hw_perf_counter_ops *
tp_perf_counter_init(struct perf_counter *counter)
{
- int event_id = counter->hw_event.type - PERF_TP_EVENTS_MIN;
+ int event_id = counter->hw_event.event_id;
int ret;

ret = ftrace_profile_enable(event_id);
@@ -1758,6 +1765,7 @@ tp_perf_counter_init(struct perf_counter
return NULL;

counter->destroy = tp_perf_counter_destroy;
+ counter->hw.irq_period = counter->hw_event.irq_period;

return &perf_ops_generic;
}
@@ -1783,7 +1791,7 @@ sw_perf_counter_init(struct perf_counter
* to be kernel events, and page faults are never hypervisor
* events.
*/
- switch (counter->hw_event.type) {
+ switch (counter->hw_event.event_id) {
case PERF_COUNT_CPU_CLOCK:
hw_ops = &perf_ops_cpu_clock;

@@ -1813,9 +1821,6 @@ sw_perf_counter_init(struct perf_counter
if (!counter->hw_event.exclude_kernel)
hw_ops = &perf_ops_cpu_migrations;
break;
- default:
- hw_ops = tp_perf_counter_init(counter);
- break;
}

if (hw_ops)
@@ -1870,10 +1875,22 @@ perf_counter_alloc(struct perf_counter_h
counter->state = PERF_COUNTER_STATE_OFF;

hw_ops = NULL;
- if (!hw_event->raw && hw_event->type < 0)
- hw_ops = sw_perf_counter_init(counter);
- else
+
+ if (hw_event->raw)
+ hw_ops = hw_perf_counter_init(counter);
+ else switch (hw_event->type) {
+ case PERF_TYPE_HARDWARE:
hw_ops = hw_perf_counter_init(counter);
+ break;
+
+ case PERF_TYPE_SOFTWARE:
+ hw_ops = sw_perf_counter_init(counter);
+ break;
+
+ case PERF_TYPE_TRACEPOINT:
+ hw_ops = tp_perf_counter_init(counter);
+ break;
+ }

if (!hw_ops) {
kfree(counter);
--



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