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 ftrace_event_call *call = &event_power;
  40         struct ring_buffer_event *event;
  41         struct trace_power *entry;
  42         struct trace_array_cpu *data;
  43         struct trace_array *tr = power_trace;
  44
  45         if (!trace_power_enabled)
  46                 return;
  47
  48         preempt_disable();
  49         it->end = ktime_get();
  50         data = tr->data[smp_processor_id()];
  51
  52         event = trace_buffer_lock_reserve(tr, TRACE_POWER,
  53                                           sizeof(*entry), 0, 0);
  54         if (!event)
  55                 goto out;
  56         entry   = ring_buffer_event_data(event);
  57         entry->state_data = *it;
  58         if (!filter_check_discard(call, entry, tr->buffer, event))
  59                 trace_buffer_unlock_commit(tr, event, 0, 0);
  60  out:
  61         preempt_enable();
  62 }
  63
  64 static void probe_power_mark(struct power_trace *it, unsigned int type,
  65                                 unsigned int level)
  66 {
  67         struct ftrace_event_call *call = &event_power;
  68         struct ring_buffer_event *event;
  69         struct trace_power *entry;
  70         struct trace_array_cpu *data;
  71         struct trace_array *tr = power_trace;
  72
  73         if (!trace_power_enabled)
  74                 return;
  75
  76         memset(it, 0, sizeof(struct power_trace));
  77         it->state = level;
  78         it->type = type;
  79         it->stamp = ktime_get();
  80         preempt_disable();
  81         it->end = it->stamp;
  82         data = tr->data[smp_processor_id()];
  83
  84         event = trace_buffer_lock_reserve(tr, TRACE_POWER,
  85                                           sizeof(*entry), 0, 0);
  86         if (!event)
  87                 goto out;
  88         entry   = ring_buffer_event_data(event);
  89         entry->state_data = *it;
  90         if (!filter_check_discard(call, entry, tr->buffer, event))
  91                 trace_buffer_unlock_commit(tr, event, 0, 0);
  92  out:
  93         preempt_enable();
  94 }
  95
  96 static int tracing_power_register(void)
  97 {
  98         int ret;
  99
 100         ret = register_trace_power_start(probe_power_start);
 101         if (ret) {
 102                 pr_info("power trace: Couldn't activate tracepoint"
 103                         " probe to trace_power_start\n");
 104                 return ret;
 105         }
 106         ret = register_trace_power_end(probe_power_end);
 107         if (ret) {
 108                 pr_info("power trace: Couldn't activate tracepoint"
 109                         " probe to trace_power_end\n");
 110                 goto fail_start;
 111         }
 112         ret = register_trace_power_mark(probe_power_mark);
 113         if (ret) {
 114                 pr_info("power trace: Couldn't activate tracepoint"
 115                         " probe to trace_power_mark\n");
 116                 goto fail_end;
 117         }
 118         return ret;
 119 fail_end:
 120         unregister_trace_power_end(probe_power_end);
 121 fail_start:
 122         unregister_trace_power_start(probe_power_start);
 123         return ret;
 124 }
 125
 126 static void start_power_trace(struct trace_array *tr)
 127 {
 128         trace_power_enabled = 1;
 129 }
 130
 131 static void stop_power_trace(struct trace_array *tr)
 132 {
 133         trace_power_enabled = 0;
 134 }
 135
 136 static void power_trace_reset(struct trace_array *tr)
 137 {
 138         trace_power_enabled = 0;
 139         unregister_trace_power_start(probe_power_start);
 140         unregister_trace_power_end(probe_power_end);
 141         unregister_trace_power_mark(probe_power_mark);
 142 }
 143
 144
 145 static int power_trace_init(struct trace_array *tr)
 146 {
 147         int cpu;
 148         power_trace = tr;
 149
 150         trace_power_enabled = 1;
 151         tracing_power_register();
 152
 153         for_each_cpu(cpu, cpu_possible_mask)
 154                 tracing_reset(tr, cpu);
 155         return 0;
 156 }
 157
 158 static enum print_line_t power_print_line(struct trace_iterator *iter)
 159 {
 160         int ret = 0;
 161         struct trace_entry *entry = iter->ent;
 162         struct trace_power *field ;
 163         struct power_trace *it;
 164         struct trace_seq *s = &iter->seq;
 165         struct timespec stamp;
 166         struct timespec duration;
 167
 168         trace_assign_type(field, entry);
 169         it = &field->state_data;
 170         stamp = ktime_to_timespec(it->stamp);
 171         duration = ktime_to_timespec(ktime_sub(it->end, it->stamp));
 172
 173         if (entry->type == TRACE_POWER) {
 174                 if (it->type == POWER_CSTATE)
 175                         ret = trace_seq_printf(s, "[%5ld.%09ld] CSTATE: Going to C%i on cpu %i for %ld.%09ld\n",
 176                                           stamp.tv_sec,
 177                                           stamp.tv_nsec,
 178                                           it->state, iter->cpu,
 179                                           duration.tv_sec,
 180                                           duration.tv_nsec);
 181                 if (it->type == POWER_PSTATE)
 182                         ret = trace_seq_printf(s, "[%5ld.%09ld] PSTATE: Going to P%i on cpu %i\n",
 183                                           stamp.tv_sec,
 184                                           stamp.tv_nsec,
 185                                           it->state, iter->cpu);
 186                 if (!ret)
 187                         return TRACE_TYPE_PARTIAL_LINE;
 188                 return TRACE_TYPE_HANDLED;
 189         }
 190         return TRACE_TYPE_UNHANDLED;
 191 }
 192
 193 static void power_print_header(struct seq_file *s)
 194 {
 195         seq_puts(s, "#   TIMESTAMP      STATE  EVENT\n");
 196         seq_puts(s, "#       |            |      |\n");
 197 }
 198
 199 static struct tracer power_tracer __read_mostly =
 200 {
 201         .name           = "power",
 202         .init           = power_trace_init,
 203         .start          = start_power_trace,
 204         .stop           = stop_power_trace,
 205         .reset          = power_trace_reset,
 206         .print_line     = power_print_line,
 207         .print_header   = power_print_header,
 208 };
 209
 210 static int init_power_trace(void)
 211 {
 212         return register_tracer(&power_tracer);
 213 }
 214 device_initcall(init_power_trace);