driver/gator_hrtimer_perf.c

   1 /**
   2  * Copyright (C) ARM Limited 2011-2013. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  */
   9
  10 // gator_hrtimer_gator.c is used if perf is not supported
  11 //   update, gator_hrtimer_gator.c always used until issues resolved with perf hrtimers
  12 #if 0
  13
  14 // Note: perf Cortex support added in 2.6.35 and PERF_COUNT_SW_CPU_CLOCK/hrtimer broken on 2.6.35 and 2.6.36
  15 //       not relevant as this code is not active until 3.0.0, but wanted to document the issue
  16
  17 void (*callback)(void);
  18 static int profiling_interval;
  19 static DEFINE_PER_CPU(struct perf_event *, perf_hrtimer);
  20 static DEFINE_PER_CPU(struct perf_event_attr *, perf_hrtimer_attr);
  21
  22 static void gator_hrtimer_shutdown(void);
  23
  24 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 1, 0)
  25 static void hrtimer_overflow_handler(struct perf_event *event, int unused, struct perf_sample_data *data, struct pt_regs *regs)
  26 #else
  27 static void hrtimer_overflow_handler(struct perf_event *event, struct perf_sample_data *data, struct pt_regs *regs)
  28 #endif
  29 {
  30         (*callback)();
  31 }
  32
  33 static int gator_online_single_hrtimer(int cpu)
  34 {
  35         if (per_cpu(perf_hrtimer, cpu) != 0 || per_cpu(perf_hrtimer_attr, cpu) == 0)
  36                 return 0;
  37
  38 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 1, 0)
  39         per_cpu(perf_hrtimer, cpu) = perf_event_create_kernel_counter(per_cpu(perf_hrtimer_attr, cpu), cpu, 0, hrtimer_overflow_handler);
  40 #else
  41         per_cpu(perf_hrtimer, cpu) = perf_event_create_kernel_counter(per_cpu(perf_hrtimer_attr, cpu), cpu, 0, hrtimer_overflow_handler, 0);
  42 #endif
  43         if (IS_ERR(per_cpu(perf_hrtimer, cpu))) {
  44                 per_cpu(perf_hrtimer, cpu) = NULL;
  45                 return -1;
  46         }
  47
  48         if (per_cpu(perf_hrtimer, cpu)->state != PERF_EVENT_STATE_ACTIVE) {
  49                 perf_event_release_kernel(per_cpu(perf_hrtimer, cpu));
  50                 per_cpu(perf_hrtimer, cpu) = NULL;
  51                 return -1;
  52         }
  53
  54         return 0;
  55 }
  56
  57 static void gator_hrtimer_online(int cpu)
  58 {
  59         if (gator_online_single_hrtimer(cpu) < 0) {
  60                 pr_debug("gator: unable to online the hrtimer on cpu%d\n", cpu);
  61         }
  62 }
  63
  64 static void gator_hrtimer_offline(int cpu)
  65 {
  66         if (per_cpu(perf_hrtimer, cpu)) {
  67                 perf_event_release_kernel(per_cpu(perf_hrtimer, cpu));
  68                 per_cpu(perf_hrtimer, cpu) = NULL;
  69         }
  70 }
  71
  72 static int gator_hrtimer_init(int interval, void (*func)(void))
  73 {
  74         u32 size = sizeof(struct perf_event_attr);
  75         int cpu;
  76
  77         callback = func;
  78
  79         // calculate profiling interval
  80         profiling_interval = 1000000000 / interval;
  81
  82         for_each_present_cpu(cpu) {
  83                 per_cpu(perf_hrtimer, cpu) = 0;
  84                 per_cpu(perf_hrtimer_attr, cpu) = kmalloc(size, GFP_KERNEL);
  85                 if (per_cpu(perf_hrtimer_attr, cpu) == 0) {
  86                         gator_hrtimer_shutdown();
  87                         return -1;
  88                 }
  89
  90                 memset(per_cpu(perf_hrtimer_attr, cpu), 0, size);
  91                 per_cpu(perf_hrtimer_attr, cpu)->type = PERF_TYPE_SOFTWARE;
  92                 per_cpu(perf_hrtimer_attr, cpu)->size = size;
  93                 per_cpu(perf_hrtimer_attr, cpu)->config = PERF_COUNT_SW_CPU_CLOCK;
  94                 per_cpu(perf_hrtimer_attr, cpu)->sample_period = profiling_interval;
  95                 per_cpu(perf_hrtimer_attr, cpu)->pinned = 1;
  96         }
  97
  98         return 0;
  99 }
 100
 101 static void gator_hrtimer_shutdown(void)
 102 {
 103         int cpu;
 104
 105         for_each_present_cpu(cpu) {
 106                 if (per_cpu(perf_hrtimer_attr, cpu)) {
 107                         kfree(per_cpu(perf_hrtimer_attr, cpu));
 108                         per_cpu(perf_hrtimer_attr, cpu) = NULL;
 109                 }
 110         }
 111 }
 112
 113 #endif