drivers/gator/gator_events_threads.c

   1 /*
   2  * Sample activity provider
   3  *
   4  * Copyright (C) ARM Limited 2014. All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * See gator_events_mmapped.c for additional directions and
  11  * troubleshooting.
  12  *
  13  * For this sample to work these entries must be present in the
  14  * events.xml file. So create an events-threads.xml in the gator
  15  * daemon source directory with the following contents and rebuild
  16  * gatord:
  17  *
  18  * <category name="threads">
  19  *   <event counter="Linux_threads" title="Linux" name="Threads" class="activity" activity1="odd" activity_color1="0x000000ff" rendering_type="bar" average_selection="yes" average_cores="yes" percentage="yes" description="Linux syscall activity"/>
  20  * </category>
  21  */
  22
  23 #include <trace/events/sched.h>
  24
  25 #include "gator.h"
  26
  27 static ulong threads_enabled;
  28 static ulong threads_key;
  29 static ulong threads_cores;
  30
  31 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 35)
  32 GATOR_DEFINE_PROBE(sched_switch, TP_PROTO(struct rq *rq, struct task_struct *prev, struct task_struct *next))
  33 #else
  34 GATOR_DEFINE_PROBE(sched_switch, TP_PROTO(struct task_struct *prev, struct task_struct *next))
  35 #endif
  36 {
  37         int cpu = get_physical_cpu();
  38         int pid = next->pid;
  39         if (pid == 0) {
  40                 // idle
  41                 gator_marshal_activity_switch(cpu, threads_key, 0, 0);
  42         } else if (pid & 1) {
  43                 // odd
  44                 gator_marshal_activity_switch(cpu, threads_key, 1, pid);
  45         } else {
  46                 // even
  47                 //gator_marshal_activity_switch(cpu, threads_key, 2, current->pid);
  48                 // Multiple activities are not yet supported so emit idle
  49                 gator_marshal_activity_switch(cpu, threads_key, 0, 0);
  50         }
  51 }
  52
  53 // Adds Linux_threads directory and enabled, key, and cores files to /dev/gator/events
  54 static int gator_events_threads_create_files(struct super_block *sb, struct dentry *root)
  55 {
  56         struct dentry *dir;
  57
  58         dir = gatorfs_mkdir(sb, root, "Linux_threads");
  59         if (!dir) {
  60                 return -1;
  61         }
  62         gatorfs_create_ulong(sb, dir, "enabled", &threads_enabled);
  63         gatorfs_create_ro_ulong(sb, dir, "key", &threads_key);
  64         // Number of cores associated with this activity
  65         gatorfs_create_ro_ulong(sb, dir, "cores", &threads_cores);
  66
  67         return 0;
  68 }
  69
  70 static int gator_events_threads_start(void)
  71 {
  72         int cpu;
  73
  74         if (threads_enabled) {
  75                 preempt_disable();
  76                 for (cpu = 0; cpu < nr_cpu_ids; ++cpu) {
  77                         gator_marshal_activity_switch(cpu, threads_key, 0, 0);
  78                 }
  79                 preempt_enable();
  80
  81                 if (GATOR_REGISTER_TRACE(sched_switch)) {
  82                         goto fail_sched_switch;
  83                 }
  84         }
  85
  86         return 0;
  87
  88 fail_sched_switch:
  89         return -1;
  90 }
  91
  92 static void gator_events_threads_stop(void)
  93 {
  94         if (threads_enabled) {
  95                 GATOR_UNREGISTER_TRACE(sched_switch);
  96         }
  97
  98         threads_enabled = 0;
  99 }
 100
 101 static struct gator_interface gator_events_threads_interface = {
 102         .create_files = gator_events_threads_create_files,
 103         .start = gator_events_threads_start,
 104         .stop = gator_events_threads_stop,
 105 };
 106
 107 // Must not be static. Ensure that this init function is added to GATOR_EVENTS_LIST in gator_main.c
 108 int __init gator_events_threads_init(void)
 109 {
 110         threads_enabled = 0;
 111         threads_key = gator_events_get_key();
 112         threads_cores = nr_cpu_ids;
 113
 114         return gator_events_install(&gator_events_threads_interface);
 115 }