osfmk/kern/kpc_thread.c

   1 /*
   2  * Copyright (c) 2012 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <mach/mach_types.h>
  30 #include <kern/processor.h>
  31 #include <kern/thread.h>
  32 #include <kern/assert.h>
  33 #include <kern/locks.h>
  34 #include <sys/errno.h>
  35
  36 #include <kperf/kperf.h>
  37 #include <kperf/buffer.h>
  38 #include <kperf/context.h>
  39 #include <kperf/sample.h>
  40 #include <kperf/action.h>
  41 #include <kperf/kperf_kpc.h>
  42 #include <kern/kpc.h>
  43
  44
  45 /* global for whether to read PMCs on context switch */
  46 int kpc_threads_counting = 0;
  47
  48 /* whether to call into KPC when a thread goes off CPU */
  49 boolean_t kpc_off_cpu_active = FALSE;
  50
  51 /* current config and number of counters in that config */
  52 static uint32_t kpc_thread_classes = 0;
  53 static uint32_t kpc_thread_classes_count = 0;
  54
  55 static lck_grp_attr_t *kpc_thread_lckgrp_attr = NULL;
  56 static lck_grp_t      *kpc_thread_lckgrp = NULL;
  57 static lck_mtx_t       kpc_thread_lock;
  58
  59 void
  60 kpc_thread_init(void)
  61 {
  62         kpc_thread_lckgrp_attr = lck_grp_attr_alloc_init();
  63         kpc_thread_lckgrp = lck_grp_alloc_init("kpc", kpc_thread_lckgrp_attr);
  64         lck_mtx_init(&kpc_thread_lock, kpc_thread_lckgrp, LCK_ATTR_NULL);
  65 }
  66
  67 uint32_t
  68 kpc_get_thread_counting(void)
  69 {
  70         uint32_t kpc_thread_classes_tmp;
  71         int kpc_threads_counting_tmp;
  72
  73         /* Make sure we get a consistent snapshot of these values */
  74         lck_mtx_lock(&kpc_thread_lock);
  75
  76         kpc_thread_classes_tmp = kpc_thread_classes;
  77         kpc_threads_counting_tmp = kpc_threads_counting;
  78
  79         lck_mtx_unlock(&kpc_thread_lock);
  80
  81         if( kpc_threads_counting_tmp )
  82                 return kpc_thread_classes_tmp;
  83         else
  84                 return 0;
  85 }
  86
  87 int
  88 kpc_set_thread_counting(uint32_t classes)
  89 {
  90         uint32_t count;
  91
  92         lck_mtx_lock(&kpc_thread_lock);
  93
  94         count = kpc_get_counter_count(classes);
  95
  96         if( (classes == 0)
  97             || (count == 0) )
  98         {
  99                 /* shut down */
 100                 kpc_threads_counting = FALSE;
 101         }
 102         else
 103         {
 104                 /* stash the config */
 105                 kpc_thread_classes = classes;
 106
 107                 /* work out the size */
 108                 kpc_thread_classes_count = count;
 109                 assert(kpc_thread_classes_count <= KPC_MAX_COUNTERS);
 110
 111                 /* enable switch */
 112                 kpc_threads_counting = TRUE;
 113
 114                 /* and schedule an AST for this thread... */
 115                 if( !current_thread()->kpc_buf )
 116                 {
 117                         current_thread()->kperf_flags |= T_KPC_ALLOC;
 118                         act_set_kperf(current_thread());
 119                 }
 120         }
 121
 122     kpc_off_cpu_update();
 123         lck_mtx_unlock(&kpc_thread_lock);
 124
 125         return 0;
 126 }
 127
 128 /* snapshot current PMCs and update counters in the current thread */
 129 static void
 130 kpc_update_thread_counters( thread_t thread )
 131 {
 132         uint32_t i;
 133         uint64_t *tmp = NULL;
 134         cpu_data_t *cpu = NULL;
 135
 136         cpu = current_cpu_datap();
 137
 138         /* 1. stash current PMCs into latest CPU block */
 139         kpc_get_cpu_counters( FALSE, kpc_thread_classes,
 140                               NULL, cpu->cpu_kpc_buf[1] );
 141
 142         /* 2. apply delta to old thread */
 143         if( thread->kpc_buf )
 144                 for( i = 0; i < kpc_thread_classes_count; i++ )
 145                         thread->kpc_buf[i] += cpu->cpu_kpc_buf[1][i] - cpu->cpu_kpc_buf[0][i];
 146
 147         /* schedule any necessary allocations */
 148         if( !current_thread()->kpc_buf )
 149         {
 150                 current_thread()->kperf_flags |= T_KPC_ALLOC;
 151                 act_set_kperf(current_thread());
 152         }
 153
 154         /* 3. switch the PMC block pointers */
 155         tmp = cpu->cpu_kpc_buf[1];
 156         cpu->cpu_kpc_buf[1] = cpu->cpu_kpc_buf[0];
 157         cpu->cpu_kpc_buf[0] = tmp;
 158 }
 159
 160 /* get counter values for a thread */
 161 int
 162 kpc_get_curthread_counters(uint32_t *inoutcount, uint64_t *buf)
 163 {
 164         thread_t thread = current_thread();
 165         boolean_t enabled;
 166
 167         /* buffer too small :( */
 168         if( *inoutcount < kpc_thread_classes_count )
 169                 return EINVAL;
 170
 171         /* copy data and actual size */
 172         if( !thread->kpc_buf )
 173                 return EINVAL;
 174
 175         enabled = ml_set_interrupts_enabled(FALSE);
 176
 177         /* snap latest version of counters for this thread */
 178         kpc_update_thread_counters( current_thread() );
 179
 180         /* copy out */
 181         memcpy( buf, thread->kpc_buf,
 182                 kpc_thread_classes_count * sizeof(*buf) );
 183         *inoutcount = kpc_thread_classes_count;
 184
 185         ml_set_interrupts_enabled(enabled);
 186
 187         return 0;
 188 }
 189
 190 void
 191 kpc_off_cpu_update(void)
 192 {
 193         kpc_off_cpu_active = kpc_threads_counting;
 194 }
 195
 196 void
 197 kpc_off_cpu_internal(thread_t thread)
 198 {
 199         if (kpc_threads_counting) {
 200                 kpc_update_thread_counters(thread);
 201         }
 202 }
 203
 204 void
 205 kpc_thread_create(thread_t thread)
 206 {
 207         /* nothing to do if we're not counting */
 208         if(!kpc_threads_counting)
 209                 return;
 210
 211         /* give the new thread a counterbuf */
 212         thread->kpc_buf = kpc_counterbuf_alloc();
 213 }
 214
 215 void
 216 kpc_thread_destroy(thread_t thread)
 217 {
 218         uint64_t *buf = NULL;
 219
 220         /* usual case: no kpc buf, just return */
 221         if( !thread->kpc_buf )
 222                 return;
 223
 224         /* otherwise, don't leak */
 225         buf = thread->kpc_buf;
 226         thread->kpc_buf = NULL;
 227         kpc_counterbuf_free(buf);
 228 }
 229
 230 /* ast callback on a thread */
 231 void
 232 kpc_thread_ast_handler( thread_t thread )
 233 {
 234         /* see if we want an alloc */
 235         if( thread->kperf_flags & T_KPC_ALLOC )
 236                 thread->kpc_buf = kpc_counterbuf_alloc();
 237 }