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 #if defined (__arm64__)
  45 #include <arm/cpu_data_internal.h>
  46 #elif defined (__arm__)
  47 #include <arm/cpu_data_internal.h>
  48 #endif
  49
  50 /* global for whether to read PMCs on context switch */
  51 int kpc_threads_counting = 0;
  52
  53 /* whether to call into KPC when a thread goes off CPU */
  54 boolean_t kpc_off_cpu_active = FALSE;
  55
  56 /* current config and number of counters in that config */
  57 static uint32_t kpc_thread_classes = 0;
  58 static uint32_t kpc_thread_classes_count = 0;
  59
  60 static LCK_GRP_DECLARE(kpc_thread_lckgrp, "kpc thread");
  61 static LCK_MTX_DECLARE(kpc_thread_lock, &kpc_thread_lckgrp);
  62
  63 uint32_t
  64 kpc_get_thread_counting(void)
  65 {
  66         uint32_t kpc_thread_classes_tmp;
  67         int kpc_threads_counting_tmp;
  68
  69         /* Make sure we get a consistent snapshot of these values */
  70         lck_mtx_lock(&kpc_thread_lock);
  71
  72         kpc_thread_classes_tmp = kpc_thread_classes;
  73         kpc_threads_counting_tmp = kpc_threads_counting;
  74
  75         lck_mtx_unlock(&kpc_thread_lock);
  76
  77         if (kpc_threads_counting_tmp) {
  78                 return kpc_thread_classes_tmp;
  79         } else {
  80                 return 0;
  81         }
  82 }
  83
  84 int
  85 kpc_set_thread_counting(uint32_t classes)
  86 {
  87         uint32_t count;
  88
  89         lck_mtx_lock(&kpc_thread_lock);
  90
  91         count = kpc_get_counter_count(classes);
  92
  93         if ((classes == 0)
  94             || (count == 0)) {
  95                 /* shut down */
  96                 kpc_threads_counting = FALSE;
  97         } else {
  98                 /* stash the config */
  99                 kpc_thread_classes = classes;
 100
 101                 /* work out the size */
 102                 kpc_thread_classes_count = count;
 103                 assert(kpc_thread_classes_count <= KPC_MAX_COUNTERS);
 104
 105                 /* enable switch */
 106                 kpc_threads_counting = TRUE;
 107
 108                 /* and schedule an AST for this thread... */
 109                 if (!current_thread()->kpc_buf) {
 110                         current_thread()->kperf_ast |= T_KPC_ALLOC;
 111                         act_set_kperf(current_thread());
 112                 }
 113         }
 114
 115         kpc_off_cpu_update();
 116         lck_mtx_unlock(&kpc_thread_lock);
 117
 118         return 0;
 119 }
 120
 121 /* snapshot current PMCs and update counters in the current thread */
 122 static void
 123 kpc_update_thread_counters( thread_t thread )
 124 {
 125         uint32_t i;
 126         uint64_t *tmp = NULL;
 127         cpu_data_t *cpu = NULL;
 128
 129         cpu = current_cpu_datap();
 130
 131         /* 1. stash current PMCs into latest CPU block */
 132         kpc_get_cpu_counters( FALSE, kpc_thread_classes,
 133             NULL, cpu->cpu_kpc_buf[1] );
 134
 135         /* 2. apply delta to old thread */
 136         if (thread->kpc_buf) {
 137                 for (i = 0; i < kpc_thread_classes_count; i++) {
 138                         thread->kpc_buf[i] += cpu->cpu_kpc_buf[1][i] - cpu->cpu_kpc_buf[0][i];
 139                 }
 140         }
 141
 142         /* schedule any necessary allocations */
 143         if (!current_thread()->kpc_buf) {
 144                 current_thread()->kperf_ast |= T_KPC_ALLOC;
 145                 act_set_kperf(current_thread());
 146         }
 147
 148         /* 3. switch the PMC block pointers */
 149         tmp = cpu->cpu_kpc_buf[1];
 150         cpu->cpu_kpc_buf[1] = cpu->cpu_kpc_buf[0];
 151         cpu->cpu_kpc_buf[0] = tmp;
 152 }
 153
 154 /* get counter values for a thread */
 155 int
 156 kpc_get_curthread_counters(uint32_t *inoutcount, uint64_t *buf)
 157 {
 158         thread_t thread = current_thread();
 159         boolean_t enabled;
 160
 161         /* buffer too small :( */
 162         if (*inoutcount < kpc_thread_classes_count) {
 163                 return EINVAL;
 164         }
 165
 166         /* copy data and actual size */
 167         if (!thread->kpc_buf) {
 168                 return EINVAL;
 169         }
 170
 171         enabled = ml_set_interrupts_enabled(FALSE);
 172
 173         /* snap latest version of counters for this thread */
 174         kpc_update_thread_counters( current_thread());
 175
 176         /* copy out */
 177         memcpy( buf, thread->kpc_buf,
 178             kpc_thread_classes_count * sizeof(*buf));
 179         *inoutcount = kpc_thread_classes_count;
 180
 181         ml_set_interrupts_enabled(enabled);
 182
 183         return 0;
 184 }
 185
 186 void
 187 kpc_off_cpu_update(void)
 188 {
 189         kpc_off_cpu_active = kpc_threads_counting;
 190 }
 191
 192 void
 193 kpc_off_cpu_internal(thread_t thread)
 194 {
 195         if (kpc_threads_counting) {
 196                 kpc_update_thread_counters(thread);
 197         }
 198 }
 199
 200 void
 201 kpc_thread_create(thread_t thread)
 202 {
 203         /* nothing to do if we're not counting */
 204         if (!kpc_threads_counting) {
 205                 return;
 206         }
 207
 208         /* give the new thread a counterbuf */
 209         thread->kpc_buf = kpc_counterbuf_alloc();
 210 }
 211
 212 void
 213 kpc_thread_destroy(thread_t thread)
 214 {
 215         uint64_t *buf = NULL;
 216
 217         /* usual case: no kpc buf, just return */
 218         if (!thread->kpc_buf) {
 219                 return;
 220         }
 221
 222         /* otherwise, don't leak */
 223         buf = thread->kpc_buf;
 224         thread->kpc_buf = NULL;
 225         kpc_counterbuf_free(buf);
 226 }
 227
 228 void
 229 kpc_thread_ast_handler(thread_t thread)
 230 {
 231         if (thread->kperf_ast & T_KPC_ALLOC) {
 232                 thread->kpc_buf = kpc_counterbuf_alloc();
 233         }
 234 }