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_attr_t *kpc_thread_lckgrp_attr = NULL;
  61 static lck_grp_t      *kpc_thread_lckgrp = NULL;
  62 static lck_mtx_t       kpc_thread_lock;
  63
  64 void
  65 kpc_thread_init(void)
  66 {
  67         kpc_thread_lckgrp_attr = lck_grp_attr_alloc_init();
  68         kpc_thread_lckgrp = lck_grp_alloc_init("kpc", kpc_thread_lckgrp_attr);
  69         lck_mtx_init(&kpc_thread_lock, kpc_thread_lckgrp, LCK_ATTR_NULL);
  70 }
  71
  72 uint32_t
  73 kpc_get_thread_counting(void)
  74 {
  75         uint32_t kpc_thread_classes_tmp;
  76         int kpc_threads_counting_tmp;
  77
  78         /* Make sure we get a consistent snapshot of these values */
  79         lck_mtx_lock(&kpc_thread_lock);
  80
  81         kpc_thread_classes_tmp = kpc_thread_classes;
  82         kpc_threads_counting_tmp = kpc_threads_counting;
  83
  84         lck_mtx_unlock(&kpc_thread_lock);
  85
  86         if (kpc_threads_counting_tmp) {
  87                 return kpc_thread_classes_tmp;
  88         } else {
  89                 return 0;
  90         }
  91 }
  92
  93 int
  94 kpc_set_thread_counting(uint32_t classes)
  95 {
  96         uint32_t count;
  97
  98         lck_mtx_lock(&kpc_thread_lock);
  99
 100         count = kpc_get_counter_count(classes);
 101
 102         if ((classes == 0)
 103             || (count == 0)) {
 104                 /* shut down */
 105                 kpc_threads_counting = FALSE;
 106         } else {
 107                 /* stash the config */
 108                 kpc_thread_classes = classes;
 109
 110                 /* work out the size */
 111                 kpc_thread_classes_count = count;
 112                 assert(kpc_thread_classes_count <= KPC_MAX_COUNTERS);
 113
 114                 /* enable switch */
 115                 kpc_threads_counting = TRUE;
 116
 117                 /* and schedule an AST for this thread... */
 118                 if (!current_thread()->kpc_buf) {
 119                         current_thread()->kperf_flags |= T_KPC_ALLOC;
 120                         act_set_kperf(current_thread());
 121                 }
 122         }
 123
 124         kpc_off_cpu_update();
 125         lck_mtx_unlock(&kpc_thread_lock);
 126
 127         return 0;
 128 }
 129
 130 /* snapshot current PMCs and update counters in the current thread */
 131 static void
 132 kpc_update_thread_counters( thread_t thread )
 133 {
 134         uint32_t i;
 135         uint64_t *tmp = NULL;
 136         cpu_data_t *cpu = NULL;
 137
 138         cpu = current_cpu_datap();
 139
 140         /* 1. stash current PMCs into latest CPU block */
 141         kpc_get_cpu_counters( FALSE, kpc_thread_classes,
 142             NULL, cpu->cpu_kpc_buf[1] );
 143
 144         /* 2. apply delta to old thread */
 145         if (thread->kpc_buf) {
 146                 for (i = 0; i < kpc_thread_classes_count; i++) {
 147                         thread->kpc_buf[i] += cpu->cpu_kpc_buf[1][i] - cpu->cpu_kpc_buf[0][i];
 148                 }
 149         }
 150
 151         /* schedule any necessary allocations */
 152         if (!current_thread()->kpc_buf) {
 153                 current_thread()->kperf_flags |= T_KPC_ALLOC;
 154                 act_set_kperf(current_thread());
 155         }
 156
 157         /* 3. switch the PMC block pointers */
 158         tmp = cpu->cpu_kpc_buf[1];
 159         cpu->cpu_kpc_buf[1] = cpu->cpu_kpc_buf[0];
 160         cpu->cpu_kpc_buf[0] = tmp;
 161 }
 162
 163 /* get counter values for a thread */
 164 int
 165 kpc_get_curthread_counters(uint32_t *inoutcount, uint64_t *buf)
 166 {
 167         thread_t thread = current_thread();
 168         boolean_t enabled;
 169
 170         /* buffer too small :( */
 171         if (*inoutcount < kpc_thread_classes_count) {
 172                 return EINVAL;
 173         }
 174
 175         /* copy data and actual size */
 176         if (!thread->kpc_buf) {
 177                 return EINVAL;
 178         }
 179
 180         enabled = ml_set_interrupts_enabled(FALSE);
 181
 182         /* snap latest version of counters for this thread */
 183         kpc_update_thread_counters( current_thread());
 184
 185         /* copy out */
 186         memcpy( buf, thread->kpc_buf,
 187             kpc_thread_classes_count * sizeof(*buf));
 188         *inoutcount = kpc_thread_classes_count;
 189
 190         ml_set_interrupts_enabled(enabled);
 191
 192         return 0;
 193 }
 194
 195 void
 196 kpc_off_cpu_update(void)
 197 {
 198         kpc_off_cpu_active = kpc_threads_counting;
 199 }
 200
 201 void
 202 kpc_off_cpu_internal(thread_t thread)
 203 {
 204         if (kpc_threads_counting) {
 205                 kpc_update_thread_counters(thread);
 206         }
 207 }
 208
 209 void
 210 kpc_thread_create(thread_t thread)
 211 {
 212         /* nothing to do if we're not counting */
 213         if (!kpc_threads_counting) {
 214                 return;
 215         }
 216
 217         /* give the new thread a counterbuf */
 218         thread->kpc_buf = kpc_counterbuf_alloc();
 219 }
 220
 221 void
 222 kpc_thread_destroy(thread_t thread)
 223 {
 224         uint64_t *buf = NULL;
 225
 226         /* usual case: no kpc buf, just return */
 227         if (!thread->kpc_buf) {
 228                 return;
 229         }
 230
 231         /* otherwise, don't leak */
 232         buf = thread->kpc_buf;
 233         thread->kpc_buf = NULL;
 234         kpc_counterbuf_free(buf);
 235 }
 236
 237 /* ast callback on a thread */
 238 void
 239 kpc_thread_ast_handler( thread_t thread )
 240 {
 241         /* see if we want an alloc */
 242         if (thread->kperf_flags & T_KPC_ALLOC) {
 243                 thread->kpc_buf = kpc_counterbuf_alloc();
 244         }
 245 }