usr.bin/flame_graph/collect.c

   1 /*
   2  * Copyright (c) 2020 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include "flame.h"
  36
  37 static void flame_disable(int sig);
  38 static void flame_collect(int ncpus);
  39 static void flame_doentry(int cpuid, uint32_t idx,
  40                         struct flame_graph_entry *fge);
  41
  42 static uint32_t *savewindex;
  43 static struct save_ctx symctx;
  44
  45 void
  46 flame_collect_loop(void)
  47 {
  48         int ncpus;
  49         int enable;
  50         int sniff = 1;
  51         int n;
  52         size_t ncpus_size = sizeof(ncpus);
  53
  54         if (sysctlbyname("hw.ncpu", &ncpus, &ncpus_size, NULL, 0) < 0) {
  55                 perror("hw.ncpu");
  56                 exit(1);
  57         }
  58         savewindex = calloc(ncpus, sizeof(*savewindex));
  59
  60         read_symbols("/boot/kernel/kernel");
  61
  62         enable = 1;
  63         signal(SIGINT, flame_disable);
  64         if (sysctlbyname("debug.flame_graph_enable",
  65                          NULL, NULL, &enable, sizeof(enable)) < 0) {
  66                 perror("debug.flame_graph_enable");
  67                 exit(1);
  68         }
  69
  70         n = 0;
  71         for (;;) {
  72                 sysctlbyname("debug.flame_graph_sniff", NULL, NULL,
  73                              &sniff, sizeof(sniff));
  74                 usleep(10000);
  75                 ++n;
  76                 if ((n & 127) == 0)
  77                         flame_collect(ncpus);
  78         }
  79         flame_disable(0);
  80 }
  81
  82 static void
  83 flame_collect(int ncpus)
  84 {
  85         struct flame_graph_pcpu *fg;
  86         struct flame_graph_entry *fge;
  87         struct flame_graph_entry *scan;
  88         void *buf;
  89         void *ptr;
  90         size_t bytes;
  91         uint32_t rindex;
  92         uint32_t windex;
  93         uint32_t delta;
  94         int n;
  95
  96         bytes = sizeof(size_t) +
  97                 sizeof(struct flame_graph_pcpu) +
  98                 sizeof(struct flame_graph_entry) * FLAME_GRAPH_NENTRIES;
  99         bytes *= ncpus;
 100         buf = malloc(bytes);
 101
 102         if (sysctlbyname("debug.flame_graph_data", buf, &bytes, NULL, 0) < 0) {
 103                 perror("debug.flame_graph_data");
 104                 exit(1);
 105         }
 106
 107         ptr = buf;
 108         for (n = 0; n < ncpus; ++n) {
 109                 if (bytes < sizeof(size_t) + sizeof(*fg))
 110                         break;
 111                 fg = (void *)((char *)ptr + sizeof(size_t));
 112                 bytes -= sizeof(size_t) + sizeof(*fg);
 113                 ptr = (char *)ptr + sizeof(size_t) + sizeof(*fg);
 114
 115                 if (bytes < sizeof(*fge) * fg->nentries)
 116                         break;
 117                 fge = (void *)(fg + 1);
 118                 ptr = (char *)ptr + sizeof(*fge) * fg->nentries;
 119                 bytes -= sizeof(*fge) * fg->nentries;
 120
 121                 rindex = savewindex[n];
 122                 windex = fg->windex;
 123
 124                 /*
 125                  * Lost data?
 126                  */
 127                 delta = windex - rindex;
 128                 if (delta >= fg->nentries)
 129                         rindex = windex - fg->nentries + 1;
 130
 131                 /*
 132                  * Process entries
 133                  */
 134                 while (rindex != windex) {
 135                         scan = &fge[rindex % fg->nentries];
 136                         if (scan->rips[0])
 137                                 flame_doentry(n, rindex, scan);
 138                         ++rindex;
 139                 }
 140                 savewindex[n] = windex;
 141         }
 142         free(buf);
 143 }
 144
 145 static void
 146 flame_doentry(int cpuid, uint32_t idx, struct flame_graph_entry *fge)
 147 {
 148         int i;
 149
 150         for (i = 0; i < FLAME_GRAPH_FRAMES; ++i) {
 151                 if (fge->rips[i] == 0)
 152                         break;
 153         }
 154
 155         printf("%03d/%03d ", cpuid, idx % 1000);
 156
 157         while (--i >= 0) {
 158                 printf(" ");
 159                 printf("%s()",
 160                        address_to_symbol((void *)fge->rips[i], &symctx));
 161         }
 162         printf("\n");
 163 }
 164
 165 /*
 166  *
 167  */
 168 static void
 169 flame_disable(int sig __unused)
 170 {
 171         int enable;
 172
 173         enable = 0;
 174         if (sysctlbyname("debug.flame_graph_enable",
 175                          NULL, NULL, &enable, sizeof(enable)) < 0) {
 176                 perror("debug.flame_graph_enable");
 177         }
 178         exit(0);
 179 }