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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-06 20:02:58 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-06 20:02:58 +0400 |
commit | 35b740e4662ef386f0c60e1b60aaf5b44db9914c (patch) | |
tree | 502a8f9499bc1b4cb3300d666dab2d01a1921224 /drivers/oprofile/nmi_timer_int.c | |
parent | 423d091dfe58d3109d84c408810a7cfa82f6f184 (diff) | |
parent | 9e183426bfb52bb44bf3c443d6587e4d02478603 (diff) | |
download | linux-35b740e4662ef386f0c60e1b60aaf5b44db9914c.tar.xz |
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (106 commits)
perf kvm: Fix copy & paste error in description
perf script: Kill script_spec__delete
perf top: Fix a memory leak
perf stat: Introduce get_ratio_color() helper
perf session: Remove impossible condition check
perf tools: Fix feature-bits rework fallout, remove unused variable
perf script: Add generic perl handler to process events
perf tools: Use for_each_set_bit() to iterate over feature flags
perf tools: Unify handling of features when writing feature section
perf report: Accept fifos as input file
perf tools: Moving code in some files
perf tools: Fix out-of-bound access to struct perf_session
perf tools: Continue processing header on unknown features
perf tools: Improve macros for struct feature_ops
perf: builtin-record: Document and check that mmap_pages must be a power of two.
perf: builtin-record: Provide advice if mmap'ing fails with EPERM.
perf tools: Fix truncated annotation
perf script: look up thread using tid instead of pid
perf tools: Look up thread names for system wide profiling
perf tools: Fix comm for processes with named threads
...
Diffstat (limited to 'drivers/oprofile/nmi_timer_int.c')
-rw-r--r-- | drivers/oprofile/nmi_timer_int.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/oprofile/nmi_timer_int.c b/drivers/oprofile/nmi_timer_int.c new file mode 100644 index 000000000000..76f1c9357f39 --- /dev/null +++ b/drivers/oprofile/nmi_timer_int.c @@ -0,0 +1,173 @@ +/** + * @file nmi_timer_int.c + * + * @remark Copyright 2011 Advanced Micro Devices, Inc. + * + * @author Robert Richter <robert.richter@amd.com> + */ + +#include <linux/init.h> +#include <linux/smp.h> +#include <linux/errno.h> +#include <linux/oprofile.h> +#include <linux/perf_event.h> + +#ifdef CONFIG_OPROFILE_NMI_TIMER + +static DEFINE_PER_CPU(struct perf_event *, nmi_timer_events); +static int ctr_running; + +static struct perf_event_attr nmi_timer_attr = { + .type = PERF_TYPE_HARDWARE, + .config = PERF_COUNT_HW_CPU_CYCLES, + .size = sizeof(struct perf_event_attr), + .pinned = 1, + .disabled = 1, +}; + +static void nmi_timer_callback(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + event->hw.interrupts = 0; /* don't throttle interrupts */ + oprofile_add_sample(regs, 0); +} + +static int nmi_timer_start_cpu(int cpu) +{ + struct perf_event *event = per_cpu(nmi_timer_events, cpu); + + if (!event) { + event = perf_event_create_kernel_counter(&nmi_timer_attr, cpu, NULL, + nmi_timer_callback, NULL); + if (IS_ERR(event)) + return PTR_ERR(event); + per_cpu(nmi_timer_events, cpu) = event; + } + + if (event && ctr_running) + perf_event_enable(event); + + return 0; +} + +static void nmi_timer_stop_cpu(int cpu) +{ + struct perf_event *event = per_cpu(nmi_timer_events, cpu); + + if (event && ctr_running) + perf_event_disable(event); +} + +static int nmi_timer_cpu_notifier(struct notifier_block *b, unsigned long action, + void *data) +{ + int cpu = (unsigned long)data; + switch (action) { + case CPU_DOWN_FAILED: + case CPU_ONLINE: + nmi_timer_start_cpu(cpu); + break; + case CPU_DOWN_PREPARE: + nmi_timer_stop_cpu(cpu); + break; + } + return NOTIFY_DONE; +} + +static struct notifier_block nmi_timer_cpu_nb = { + .notifier_call = nmi_timer_cpu_notifier +}; + +static int nmi_timer_start(void) +{ + int cpu; + + get_online_cpus(); + ctr_running = 1; + for_each_online_cpu(cpu) + nmi_timer_start_cpu(cpu); + put_online_cpus(); + + return 0; +} + +static void nmi_timer_stop(void) +{ + int cpu; + + get_online_cpus(); + for_each_online_cpu(cpu) + nmi_timer_stop_cpu(cpu); + ctr_running = 0; + put_online_cpus(); +} + +static void nmi_timer_shutdown(void) +{ + struct perf_event *event; + int cpu; + + get_online_cpus(); + unregister_cpu_notifier(&nmi_timer_cpu_nb); + for_each_possible_cpu(cpu) { + event = per_cpu(nmi_timer_events, cpu); + if (!event) + continue; + perf_event_disable(event); + per_cpu(nmi_timer_events, cpu) = NULL; + perf_event_release_kernel(event); + } + + put_online_cpus(); +} + +static int nmi_timer_setup(void) +{ + int cpu, err; + u64 period; + + /* clock cycles per tick: */ + period = (u64)cpu_khz * 1000; + do_div(period, HZ); + nmi_timer_attr.sample_period = period; + + get_online_cpus(); + err = register_cpu_notifier(&nmi_timer_cpu_nb); + if (err) + goto out; + /* can't attach events to offline cpus: */ + for_each_online_cpu(cpu) { + err = nmi_timer_start_cpu(cpu); + if (err) + break; + } + if (err) + nmi_timer_shutdown(); +out: + put_online_cpus(); + return err; +} + +int __init op_nmi_timer_init(struct oprofile_operations *ops) +{ + int err = 0; + + err = nmi_timer_setup(); + if (err) + return err; + nmi_timer_shutdown(); /* only check, don't alloc */ + + ops->create_files = NULL; + ops->setup = nmi_timer_setup; + ops->shutdown = nmi_timer_shutdown; + ops->start = nmi_timer_start; + ops->stop = nmi_timer_stop; + ops->cpu_type = "timer"; + + printk(KERN_INFO "oprofile: using NMI timer interrupt.\n"); + + return 0; +} + +#endif |