perf counters: hw driver API
Impact: restructure code, introduce hw_ops driver abstraction
Introduce this abstraction to handle counter details:
struct hw_perf_counter_ops {
void (*hw_perf_counter_enable) (struct perf_counter *counter);
void (*hw_perf_counter_disable) (struct perf_counter *counter);
void (*hw_perf_counter_read) (struct perf_counter *counter);
};
This will be useful to support assymetric hw details, and it will also
be useful to implement "software counters". (Counters that count kernel
managed sw events such as pagefaults, context-switches, wall-clock time
or task-local time.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index 54b4ad0..718b635 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -56,7 +56,7 @@
/*
* Setup the hardware configuration for a given hw_event_type
*/
-int hw_perf_counter_init(struct perf_counter *counter)
+static int __hw_perf_counter_init(struct perf_counter *counter)
{
struct perf_counter_hw_event *hw_event = &counter->hw_event;
struct hw_perf_counter *hwc = &counter->hw;
@@ -135,7 +135,7 @@
EXPORT_SYMBOL_GPL(hw_perf_disable_all);
static inline void
-__hw_perf_counter_disable(struct hw_perf_counter *hwc, unsigned int idx)
+__x86_perf_counter_disable(struct hw_perf_counter *hwc, unsigned int idx)
{
wrmsr(hwc->config_base + idx, hwc->config, 0);
}
@@ -149,13 +149,13 @@
wrmsr(hwc->counter_base + idx, hwc->next_count, 0);
}
-static void __hw_perf_counter_enable(struct hw_perf_counter *hwc, int idx)
+static void __x86_perf_counter_enable(struct hw_perf_counter *hwc, int idx)
{
wrmsr(hwc->config_base + idx,
hwc->config | ARCH_PERFMON_EVENTSEL0_ENABLE, 0);
}
-void hw_perf_counter_enable(struct perf_counter *counter)
+static void x86_perf_counter_enable(struct perf_counter *counter)
{
struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
struct hw_perf_counter *hwc = &counter->hw;
@@ -170,12 +170,12 @@
perf_counters_lapic_init(hwc->nmi);
- __hw_perf_counter_disable(hwc, idx);
+ __x86_perf_counter_disable(hwc, idx);
cpuc->counters[idx] = counter;
__hw_perf_counter_set_period(hwc, idx);
- __hw_perf_counter_enable(hwc, idx);
+ __x86_perf_counter_enable(hwc, idx);
}
#ifdef CONFIG_X86_64
@@ -282,20 +282,20 @@
local_irq_enable();
}
-void hw_perf_counter_disable(struct perf_counter *counter)
+static void x86_perf_counter_disable(struct perf_counter *counter)
{
struct cpu_hw_counters *cpuc = &__get_cpu_var(cpu_hw_counters);
struct hw_perf_counter *hwc = &counter->hw;
unsigned int idx = hwc->idx;
- __hw_perf_counter_disable(hwc, idx);
+ __x86_perf_counter_disable(hwc, idx);
clear_bit(idx, cpuc->used);
cpuc->counters[idx] = NULL;
__hw_perf_save_counter(counter, hwc, idx);
}
-void hw_perf_counter_read(struct perf_counter *counter)
+static void x86_perf_counter_read(struct perf_counter *counter)
{
struct hw_perf_counter *hwc = &counter->hw;
unsigned long addr = hwc->counter_base + hwc->idx;
@@ -342,7 +342,7 @@
__hw_perf_counter_set_period(hwc, idx);
if (pmc_ctrl & ARCH_PERFMON_EVENTSEL0_ENABLE)
- __hw_perf_counter_enable(hwc, idx);
+ __x86_perf_counter_enable(hwc, idx);
}
static void
@@ -572,3 +572,20 @@
perf_counters_initialized = true;
}
+
+static struct hw_perf_counter_ops x86_perf_counter_ops = {
+ .hw_perf_counter_enable = x86_perf_counter_enable,
+ .hw_perf_counter_disable = x86_perf_counter_disable,
+ .hw_perf_counter_read = x86_perf_counter_read,
+};
+
+struct hw_perf_counter_ops *hw_perf_counter_init(struct perf_counter *counter)
+{
+ int err;
+
+ err = __hw_perf_counter_init(counter);
+ if (err)
+ return NULL;
+
+ return &x86_perf_counter_ops;
+}
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 7af7d89..2738564 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -113,6 +113,17 @@
u8 data[PERF_DATA_BUFLEN];
};
+struct perf_counter;
+
+/**
+ * struct hw_perf_counter_ops - performance counter hw ops
+ */
+struct hw_perf_counter_ops {
+ void (*hw_perf_counter_enable) (struct perf_counter *counter);
+ void (*hw_perf_counter_disable) (struct perf_counter *counter);
+ void (*hw_perf_counter_read) (struct perf_counter *counter);
+};
+
/**
* struct perf_counter - performance counter kernel representation:
*/
@@ -120,6 +131,7 @@
struct list_head list_entry;
struct list_head sibling_list;
struct perf_counter *group_leader;
+ struct hw_perf_counter_ops *hw_ops;
int active;
#if BITS_PER_LONG == 64
@@ -185,6 +197,9 @@
extern int perf_max_counters;
#ifdef CONFIG_PERF_COUNTERS
+extern struct hw_perf_counter_ops *
+hw_perf_counter_init(struct perf_counter *counter);
+
extern void perf_counter_task_sched_in(struct task_struct *task, int cpu);
extern void perf_counter_task_sched_out(struct task_struct *task, int cpu);
extern void perf_counter_task_tick(struct task_struct *task, int cpu);
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 278209c..e6e41ca 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -37,18 +37,15 @@
/*
* Architecture provided APIs - weak aliases:
*/
-
-int __weak hw_perf_counter_init(struct perf_counter *counter)
+extern __weak struct hw_perf_counter_ops *
+hw_perf_counter_init(struct perf_counter *counter)
{
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
}
-void __weak hw_perf_counter_enable(struct perf_counter *counter) { }
-void __weak hw_perf_counter_disable(struct perf_counter *counter) { }
-void __weak hw_perf_counter_read(struct perf_counter *counter) { }
-void __weak hw_perf_disable_all(void) { }
-void __weak hw_perf_enable_all(void) { }
-void __weak hw_perf_counter_setup(void) { }
+void __weak hw_perf_disable_all(void) { }
+void __weak hw_perf_enable_all(void) { }
+void __weak hw_perf_counter_setup(void) { }
#if BITS_PER_LONG == 64
@@ -146,7 +143,7 @@
spin_lock(&ctx->lock);
if (counter->active) {
- hw_perf_counter_disable(counter);
+ counter->hw_ops->hw_perf_counter_disable(counter);
counter->active = 0;
ctx->nr_active--;
cpuctx->active_oncpu--;
@@ -257,7 +254,7 @@
ctx->nr_counters++;
if (cpuctx->active_oncpu < perf_max_counters) {
- hw_perf_counter_enable(counter);
+ counter->hw_ops->hw_perf_counter_enable(counter);
counter->active = 1;
counter->oncpu = cpu;
ctx->nr_active++;
@@ -333,7 +330,7 @@
if (!counter->active)
return;
- hw_perf_counter_disable(counter);
+ counter->hw_ops->hw_perf_counter_disable(counter);
counter->active = 0;
counter->oncpu = -1;
@@ -392,7 +389,7 @@
struct perf_counter_context *ctx,
int cpu)
{
- hw_perf_counter_enable(counter);
+ counter->hw_ops->hw_perf_counter_enable(counter);
counter->active = 1;
counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */
@@ -509,7 +506,9 @@
*/
static void __hw_perf_counter_read(void *info)
{
- hw_perf_counter_read(info);
+ struct perf_counter *counter = info;
+
+ counter->hw_ops->hw_perf_counter_read(counter);
}
static u64 perf_counter_read(struct perf_counter *counter)
@@ -816,8 +815,10 @@
int cpu,
struct perf_counter *group_leader)
{
- struct perf_counter *counter = kzalloc(sizeof(*counter), GFP_KERNEL);
+ struct hw_perf_counter_ops *hw_ops;
+ struct perf_counter *counter;
+ counter = kzalloc(sizeof(*counter), GFP_KERNEL);
if (!counter)
return NULL;
@@ -839,6 +840,14 @@
counter->hw_event = *hw_event;
counter->wakeup_pending = 0;
counter->group_leader = group_leader;
+ counter->hw_ops = NULL;
+
+ hw_ops = hw_perf_counter_init(counter);
+ if (!hw_ops) {
+ kfree(counter);
+ return NULL;
+ }
+ counter->hw_ops = hw_ops;
return counter;
}
@@ -908,10 +917,6 @@
if (!counter)
goto err_put_context;
- ret = hw_perf_counter_init(counter);
- if (ret)
- goto err_free_put_context;
-
perf_install_in_context(ctx, counter, cpu);
ret = anon_inode_getfd("[perf_counter]", &perf_fops, counter, 0);
@@ -927,8 +932,6 @@
mutex_lock(&counter->mutex);
perf_counter_remove_from_context(counter);
mutex_unlock(&counter->mutex);
-
-err_free_put_context:
kfree(counter);
err_put_context: