kernel/trace/trace_power.c

   1 /*
   2  * ring buffer based C-state tracer
   3  *
   4  * Arjan van de Ven <arjan@linux.intel.com>
   5  * Copyright (C) 2008 Intel Corporation
   6  *
   7  * Much is borrowed from trace_boot.c which is
   8  * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
   9  *
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/debugfs.h>
  14 #include <linux/ftrace.h>
  15 #include <linux/kallsyms.h>
  16 #include <linux/module.h>
  17
  18 #include "trace.h"
  19 #include "trace_output.h"
  20
  21 static struct trace_array *power_trace;
  22 static int __read_mostly trace_power_enabled;
  23
  24
  25 static void start_power_trace(struct trace_array *tr)
  26 {
  27         trace_power_enabled = 1;
  28 }
  29
  30 static void stop_power_trace(struct trace_array *tr)
  31 {
  32         trace_power_enabled = 0;
  33 }
  34
  35
  36 static int power_trace_init(struct trace_array *tr)
  37 {
  38         int cpu;
  39         power_trace = tr;
  40
  41         trace_power_enabled = 1;
  42
  43         for_each_cpu_mask(cpu, cpu_possible_map)
  44                 tracing_reset(tr, cpu);
  45         return 0;
  46 }
  47
  48 static enum print_line_t power_print_line(struct trace_iterator *iter)
  49 {
  50         int ret = 0;
  51         struct trace_entry *entry = iter->ent;
  52         struct trace_power *field ;
  53         struct power_trace *it;
  54         struct trace_seq *s = &iter->seq;
  55         struct timespec stamp;
  56         struct timespec duration;
  57
  58         trace_assign_type(field, entry);
  59         it = &field->state_data;
  60         stamp = ktime_to_timespec(it->stamp);
  61         duration = ktime_to_timespec(ktime_sub(it->end, it->stamp));
  62
  63         if (entry->type == TRACE_POWER) {
  64                 if (it->type == POWER_CSTATE)
  65                         ret = trace_seq_printf(s, "[%5ld.%09ld] CSTATE: Going to C%i on cpu %i for %ld.%09ld\n",
  66                                           stamp.tv_sec,
  67                                           stamp.tv_nsec,
  68                                           it->state, iter->cpu,
  69                                           duration.tv_sec,
  70                                           duration.tv_nsec);
  71                 if (it->type == POWER_PSTATE)
  72                         ret = trace_seq_printf(s, "[%5ld.%09ld] PSTATE: Going to P%i on cpu %i\n",
  73                                           stamp.tv_sec,
  74                                           stamp.tv_nsec,
  75                                           it->state, iter->cpu);
  76                 if (!ret)
  77                         return TRACE_TYPE_PARTIAL_LINE;
  78                 return TRACE_TYPE_HANDLED;
  79         }
  80         return TRACE_TYPE_UNHANDLED;
  81 }
  82
  83 static struct tracer power_tracer __read_mostly =
  84 {
  85         .name           = "power",
  86         .init           = power_trace_init,
  87         .start          = start_power_trace,
  88         .stop           = stop_power_trace,
  89         .reset          = stop_power_trace,
  90         .print_line     = power_print_line,
  91 };
  92
  93 static int init_power_trace(void)
  94 {
  95         return register_tracer(&power_tracer);
  96 }
  97 device_initcall(init_power_trace);
  98
  99 void trace_power_start(struct power_trace *it, unsigned int type,
 100                          unsigned int level)
 101 {
 102         if (!trace_power_enabled)
 103                 return;
 104
 105         memset(it, 0, sizeof(struct power_trace));
 106         it->state = level;
 107         it->type = type;
 108         it->stamp = ktime_get();
 109 }
 110 EXPORT_SYMBOL_GPL(trace_power_start);
 111
 112
 113 void trace_power_end(struct power_trace *it)
 114 {
 115         struct ring_buffer_event *event;
 116         struct trace_power *entry;
 117         struct trace_array_cpu *data;
 118         unsigned long irq_flags;
 119         struct trace_array *tr = power_trace;
 120
 121         if (!trace_power_enabled)
 122                 return;
 123
 124         preempt_disable();
 125         it->end = ktime_get();
 126         data = tr->data[smp_processor_id()];
 127
 128         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 129                                          &irq_flags);
 130         if (!event)
 131                 goto out;
 132         entry   = ring_buffer_event_data(event);
 133         tracing_generic_entry_update(&entry->ent, 0, 0);
 134         entry->ent.type = TRACE_POWER;
 135         entry->state_data = *it;
 136         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 137
 138         trace_wake_up();
 139
 140  out:
 141         preempt_enable();
 142 }
 143 EXPORT_SYMBOL_GPL(trace_power_end);
 144
 145 void trace_power_mark(struct power_trace *it, unsigned int type,
 146                          unsigned int level)
 147 {
 148         struct ring_buffer_event *event;
 149         struct trace_power *entry;
 150         struct trace_array_cpu *data;
 151         unsigned long irq_flags;
 152         struct trace_array *tr = power_trace;
 153
 154         if (!trace_power_enabled)
 155                 return;
 156
 157         memset(it, 0, sizeof(struct power_trace));
 158         it->state = level;
 159         it->type = type;
 160         it->stamp = ktime_get();
 161         preempt_disable();
 162         it->end = it->stamp;
 163         data = tr->data[smp_processor_id()];
 164
 165         event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
 166                                          &irq_flags);
 167         if (!event)
 168                 goto out;
 169         entry   = ring_buffer_event_data(event);
 170         tracing_generic_entry_update(&entry->ent, 0, 0);
 171         entry->ent.type = TRACE_POWER;
 172         entry->state_data = *it;
 173         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 174
 175         trace_wake_up();
 176
 177  out:
 178         preempt_enable();
 179 }
 180 EXPORT_SYMBOL_GPL(trace_power_mark);