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 <trace/power.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 static void probe_power_start(struct power_trace *it, unsigned int type,
  25                                 unsigned int level)
  26 {
  27         if (!trace_power_enabled)
  28                 return;
  29
  30         memset(it, 0, sizeof(struct power_trace));
  31         it->state = level;
  32         it->type = type;
  33         it->stamp = ktime_get();
  34 }
  35
  36
  37 static void probe_power_end(struct power_trace *it)
  38 {
  39         struct ring_buffer_event *event;
  40         struct trace_power *entry;
  41         struct trace_array_cpu *data;
  42         struct trace_array *tr = power_trace;
  43
  44         if (!trace_power_enabled)
  45                 return;
  46
  47         preempt_disable();
  48         it->end = ktime_get();
  49         data = tr->data[smp_processor_id()];
  50
  51         event = trace_buffer_lock_reserve(tr, TRACE_POWER,
  52                                           sizeof(*entry), 0, 0);
  53         if (!event)
  54                 goto out;
  55         entry   = ring_buffer_event_data(event);
  56         entry->state_data = *it;
  57         trace_buffer_unlock_commit(tr, event, 0, 0);
  58  out:
  59         preempt_enable();
  60 }
  61
  62 static void probe_power_mark(struct power_trace *it, unsigned int type,
  63                                 unsigned int level)
  64 {
  65         struct ring_buffer_event *event;
  66         struct trace_power *entry;
  67         struct trace_array_cpu *data;
  68         struct trace_array *tr = power_trace;
  69
  70         if (!trace_power_enabled)
  71                 return;
  72
  73         memset(it, 0, sizeof(struct power_trace));
  74         it->state = level;
  75         it->type = type;
  76         it->stamp = ktime_get();
  77         preempt_disable();
  78         it->end = it->stamp;
  79         data = tr->data[smp_processor_id()];
  80
  81         event = trace_buffer_lock_reserve(tr, TRACE_POWER,
  82                                           sizeof(*entry), 0, 0);
  83         if (!event)
  84                 goto out;
  85         entry   = ring_buffer_event_data(event);
  86         entry->state_data = *it;
  87         trace_buffer_unlock_commit(tr, event, 0, 0);
  88  out:
  89         preempt_enable();
  90 }
  91
  92 static int tracing_power_register(void)
  93 {
  94         int ret;
  95
  96         ret = register_trace_power_start(probe_power_start);
  97         if (ret) {
  98                 pr_info("power trace: Couldn't activate tracepoint"
  99                         " probe to trace_power_start\n");
 100                 return ret;
 101         }
 102         ret = register_trace_power_end(probe_power_end);
 103         if (ret) {
 104                 pr_info("power trace: Couldn't activate tracepoint"
 105                         " probe to trace_power_end\n");
 106                 goto fail_start;
 107         }
 108         ret = register_trace_power_mark(probe_power_mark);
 109         if (ret) {
 110                 pr_info("power trace: Couldn't activate tracepoint"
 111                         " probe to trace_power_mark\n");
 112                 goto fail_end;
 113         }
 114         return ret;
 115 fail_end:
 116         unregister_trace_power_end(probe_power_end);
 117 fail_start:
 118         unregister_trace_power_start(probe_power_start);
 119         return ret;
 120 }
 121
 122 static void start_power_trace(struct trace_array *tr)
 123 {
 124         trace_power_enabled = 1;
 125 }
 126
 127 static void stop_power_trace(struct trace_array *tr)
 128 {
 129         trace_power_enabled = 0;
 130 }
 131
 132 static void power_trace_reset(struct trace_array *tr)
 133 {
 134         trace_power_enabled = 0;
 135         unregister_trace_power_start(probe_power_start);
 136         unregister_trace_power_end(probe_power_end);
 137         unregister_trace_power_mark(probe_power_mark);
 138 }
 139
 140
 141 static int power_trace_init(struct trace_array *tr)
 142 {
 143         int cpu;
 144         power_trace = tr;
 145
 146         trace_power_enabled = 1;
 147         tracing_power_register();
 148
 149         for_each_cpu(cpu, cpu_possible_mask)
 150                 tracing_reset(tr, cpu);
 151         return 0;
 152 }
 153
 154 static enum print_line_t power_print_line(struct trace_iterator *iter)
 155 {
 156         int ret = 0;
 157         struct trace_entry *entry = iter->ent;
 158         struct trace_power *field ;
 159         struct power_trace *it;
 160         struct trace_seq *s = &iter->seq;
 161         struct timespec stamp;
 162         struct timespec duration;
 163
 164         trace_assign_type(field, entry);
 165         it = &field->state_data;
 166         stamp = ktime_to_timespec(it->stamp);
 167         duration = ktime_to_timespec(ktime_sub(it->end, it->stamp));
 168
 169         if (entry->type == TRACE_POWER) {
 170                 if (it->type == POWER_CSTATE)
 171                         ret = trace_seq_printf(s, "[%5ld.%09ld] CSTATE: Going to C%i on cpu %i for %ld.%09ld\n",
 172                                           stamp.tv_sec,
 173                                           stamp.tv_nsec,
 174                                           it->state, iter->cpu,
 175                                           duration.tv_sec,
 176                                           duration.tv_nsec);
 177                 if (it->type == POWER_PSTATE)
 178                         ret = trace_seq_printf(s, "[%5ld.%09ld] PSTATE: Going to P%i on cpu %i\n",
 179                                           stamp.tv_sec,
 180                                           stamp.tv_nsec,
 181                                           it->state, iter->cpu);
 182                 if (!ret)
 183                         return TRACE_TYPE_PARTIAL_LINE;
 184                 return TRACE_TYPE_HANDLED;
 185         }
 186         return TRACE_TYPE_UNHANDLED;
 187 }
 188
 189 static void power_print_header(struct seq_file *s)
 190 {
 191         seq_puts(s, "#   TIMESTAMP      STATE  EVENT\n");
 192         seq_puts(s, "#       |            |      |\n");
 193 }
 194
 195 static struct tracer power_tracer __read_mostly =
 196 {
 197         .name           = "power",
 198         .init           = power_trace_init,
 199         .start          = start_power_trace,
 200         .stop           = stop_power_trace,
 201         .reset          = power_trace_reset,
 202         .print_line     = power_print_line,
 203         .print_header   = power_print_header,
 204 };
 205
 206 static int init_power_trace(void)
 207 {
 208         return register_tracer(&power_tracer);
 209 }
 210 device_initcall(init_power_trace);