Re: [PATCH 1/7] perf: Add helper function to return number ofcounters
From: Robert Richter
Date: Wed Oct 06 2010 - 08:14:42 EST
On 04.10.10 16:44:19, Matt Fleming wrote:
> The number of counters for the registered pmu is needed in a few places
> so provide a helper function that returns this number.
>
> Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxx>
> Tested-by: Will Deacon <will.deacon@xxxxxxx>
> ---
> arch/arm/kernel/perf_event.c | 6 ++++++
> arch/arm/oprofile/common.c | 31 ++++++++++++++++++-------------
> arch/sh/kernel/perf_event.c | 9 +++++++++
> include/linux/perf_event.h | 1 +
> 4 files changed, 34 insertions(+), 13 deletions(-)
>
> diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
> index ecbb028..ef3bc33 100644
> --- a/arch/arm/kernel/perf_event.c
> +++ b/arch/arm/kernel/perf_event.c
> @@ -123,6 +123,12 @@ armpmu_get_max_events(void)
> }
> EXPORT_SYMBOL_GPL(armpmu_get_max_events);
>
> +int perf_num_counters(void)
> +{
> + return armpmu_get_max_events();
> +}
> +EXPORT_SYMBOL_GPL(perf_num_counters);
Peter,
can you please ack this interface?
Thanks,
-Robert
> +
> #define HW_OP_UNSUPPORTED 0xFFFF
>
> #define C(_x) \
> diff --git a/arch/arm/oprofile/common.c b/arch/arm/oprofile/common.c
> index d660cb8..23f18a0 100644
> --- a/arch/arm/oprofile/common.c
> +++ b/arch/arm/oprofile/common.c
> @@ -43,7 +43,7 @@ static DEFINE_MUTEX(op_arm_mutex);
>
> static struct op_counter_config *counter_config;
> static struct perf_event **perf_events[nr_cpumask_bits];
> -static int perf_num_counters;
> +static int perf_nr_counters;
>
> /*
> * Overflow callback for oprofile.
> @@ -54,11 +54,11 @@ static void op_overflow_handler(struct perf_event *event, int unused,
> int id;
> u32 cpu = smp_processor_id();
>
> - for (id = 0; id < perf_num_counters; ++id)
> + for (id = 0; id < perf_nr_counters; ++id)
> if (perf_events[cpu][id] == event)
> break;
>
> - if (id != perf_num_counters)
> + if (id != perf_nr_counters)
> oprofile_add_sample(regs, id);
> else
> pr_warning("oprofile: ignoring spurious overflow "
> @@ -76,7 +76,7 @@ static void op_perf_setup(void)
> u32 size = sizeof(struct perf_event_attr);
> struct perf_event_attr *attr;
>
> - for (i = 0; i < perf_num_counters; ++i) {
> + for (i = 0; i < perf_nr_counters; ++i) {
> attr = &counter_config[i].attr;
> memset(attr, 0, size);
> attr->type = PERF_TYPE_RAW;
> @@ -131,7 +131,7 @@ static int op_perf_start(void)
> int cpu, event, ret = 0;
>
> for_each_online_cpu(cpu) {
> - for (event = 0; event < perf_num_counters; ++event) {
> + for (event = 0; event < perf_nr_counters; ++event) {
> ret = op_create_counter(cpu, event);
> if (ret)
> goto out;
> @@ -150,7 +150,7 @@ static void op_perf_stop(void)
> int cpu, event;
>
> for_each_online_cpu(cpu)
> - for (event = 0; event < perf_num_counters; ++event)
> + for (event = 0; event < perf_nr_counters; ++event)
> op_destroy_counter(cpu, event);
> }
>
> @@ -179,7 +179,7 @@ static int op_arm_create_files(struct super_block *sb, struct dentry *root)
> {
> unsigned int i;
>
> - for (i = 0; i < perf_num_counters; i++) {
> + for (i = 0; i < perf_nr_counters; i++) {
> struct dentry *dir;
> char buf[4];
>
> @@ -353,14 +353,19 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
>
> memset(&perf_events, 0, sizeof(perf_events));
>
> - perf_num_counters = armpmu_get_max_events();
> + perf_nr_counters = perf_num_counters();
> + if (perf_nr_counters <= 0) {
> + pr_info("oprofile: no performance counters\n");
> + ret = -ENODEV;
> + goto out;
> + }
>
> - counter_config = kcalloc(perf_num_counters,
> + counter_config = kcalloc(perf_nr_counters,
> sizeof(struct op_counter_config), GFP_KERNEL);
>
> if (!counter_config) {
> pr_info("oprofile: failed to allocate %d "
> - "counters\n", perf_num_counters);
> + "counters\n", perf_nr_counters);
> ret = -ENOMEM;
> goto out;
> }
> @@ -370,11 +375,11 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
> goto out;
>
> for_each_possible_cpu(cpu) {
> - perf_events[cpu] = kcalloc(perf_num_counters,
> + perf_events[cpu] = kcalloc(perf_nr_counters,
> sizeof(struct perf_event *), GFP_KERNEL);
> if (!perf_events[cpu]) {
> pr_info("oprofile: failed to allocate %d perf events "
> - "for cpu %d\n", perf_num_counters, cpu);
> + "for cpu %d\n", perf_nr_counters, cpu);
> ret = -ENOMEM;
> goto out;
> }
> @@ -409,7 +414,7 @@ void __exit oprofile_arch_exit(void)
> struct perf_event *event;
>
> for_each_possible_cpu(cpu) {
> - for (id = 0; id < perf_num_counters; ++id) {
> + for (id = 0; id < perf_nr_counters; ++id) {
> event = perf_events[cpu][id];
> if (event)
> perf_event_release_kernel(event);
> diff --git a/arch/sh/kernel/perf_event.c b/arch/sh/kernel/perf_event.c
> index 7a3dc35..2cb9ad5 100644
> --- a/arch/sh/kernel/perf_event.c
> +++ b/arch/sh/kernel/perf_event.c
> @@ -59,6 +59,15 @@ static inline int sh_pmu_initialized(void)
> return !!sh_pmu;
> }
>
> +int perf_num_counters(void)
> +{
> + if (!sh_pmu)
> + return 0;
> +
> + return sh_pmu->num_events;
> +}
> +EXPORT_SYMBOL_GPL(perf_num_counters);
> +
> /*
> * Release the PMU if this is the last perf_event.
> */
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 716f99b..1a02192 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -849,6 +849,7 @@ extern int perf_max_events;
>
> extern const struct pmu *hw_perf_event_init(struct perf_event *event);
>
> +extern int perf_num_counters(void);
> extern void perf_event_task_sched_in(struct task_struct *task);
> extern void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next);
> extern void perf_event_task_tick(struct task_struct *task);
> --
> 1.7.1
>
>
--
Advanced Micro Devices, Inc.
Operating System Research Center
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