src/proc_softirqs.c

   1 #include "common.h"
   2
   3 #define MAX_INTERRUPT_NAME 50
   4
   5 struct interrupt {
   6         int used;
   7         char *id;
   8         char name[MAX_INTERRUPT_NAME + 1];
   9         unsigned long long total;
  10         unsigned long long value[];
  11 };
  12
  13 // since each interrupt is variable in size
  14 // we use this to calculate its record size
  15 #define recordsize(cpus) (sizeof(struct interrupt) + (cpus * sizeof(unsigned long long)))
  16
  17 // given a base, get a pointer to each record
  18 #define irrindex(base, line, cpus) ((struct interrupt *)&((char *)(base))[line * recordsize(cpus)])
  19
  20 static inline struct interrupt *get_interrupts_array(int lines, int cpus) {
  21         static struct interrupt *irrs = NULL;
  22         static int allocated = 0;
  23
  24         if(lines < allocated) return irrs;
  25         else {
  26                 irrs = (struct interrupt *)realloc(irrs, lines * recordsize(cpus));
  27                 if(!irrs)
  28                         fatal("Cannot allocate memory for %d interrupts", lines);
  29
  30                 allocated = lines;
  31         }
  32
  33         return irrs;
  34 }
  35
  36 int do_proc_softirqs(int update_every, unsigned long long dt) {
  37         static procfile *ff = NULL;
  38         static int cpus = -1, do_per_core = -1;
  39
  40         struct interrupt *irrs = NULL;
  41
  42         if(dt) {};
  43
  44         if(do_per_core == -1) do_per_core = config_get_boolean("plugin:proc:/proc/softirqs", "interrupts per core", 1);
  45
  46         if(!ff) {
  47                 char filename[FILENAME_MAX + 1];
  48                 snprintfz(filename, FILENAME_MAX, "%s%s", global_host_prefix, "/proc/softirqs");
  49                 ff = procfile_open(config_get("plugin:proc:/proc/softirqs", "filename to monitor", filename), " \t", PROCFILE_FLAG_DEFAULT);
  50         }
  51         if(!ff) return 1;
  52
  53         ff = procfile_readall(ff);
  54         if(!ff) return 0; // we return 0, so that we will retry to open it next time
  55
  56         uint32_t lines = procfile_lines(ff), l;
  57         uint32_t words = procfile_linewords(ff, 0), w;
  58
  59         if(!lines) {
  60                 error("Cannot read /proc/softirqs, zero lines reported.");
  61                 return 1;
  62         }
  63
  64         // find how many CPUs are there
  65         if(cpus == -1) {
  66                 cpus = 0;
  67                 for(w = 0; w < words ; w++) {
  68                         if(strncmp(procfile_lineword(ff, 0, w), "CPU", 3) == 0)
  69                                 cpus++;
  70                 }
  71         }
  72
  73         if(!cpus) {
  74                 error("PLUGIN: PROC_SOFTIRQS: Cannot find the number of CPUs in /proc/softirqs");
  75                 return 1;
  76         }
  77
  78         // allocate the size we need;
  79         irrs = get_interrupts_array(lines, cpus);
  80         irrs[0].used = 0;
  81
  82         // loop through all lines
  83         for(l = 1; l < lines ;l++) {
  84                 struct interrupt *irr = irrindex(irrs, l, cpus);
  85                 irr->used = 0;
  86                 irr->total = 0;
  87
  88                 words = procfile_linewords(ff, l);
  89                 if(!words) continue;
  90
  91                 irr->id = procfile_lineword(ff, l, 0);
  92                 if(!irr->id || !irr->id[0]) continue;
  93
  94                 int idlen = strlen(irr->id);
  95                 if(irr->id[idlen - 1] == ':')
  96                         irr->id[idlen - 1] = '\0';
  97
  98                 int c;
  99                 for(c = 0; c < cpus ;c++) {
 100                         if((c + 1) < (int)words)
 101                                 irr->value[c] = strtoull(procfile_lineword(ff, l, (uint32_t)(c + 1)), NULL, 10);
 102                         else
 103                                 irr->value[c] = 0;
 104
 105                         irr->total += irr->value[c];
 106                 }
 107
 108                 strncpyz(irr->name, irr->id, MAX_INTERRUPT_NAME);
 109
 110                 irr->used = 1;
 111         }
 112
 113         RRDSET *st;
 114
 115         // --------------------------------------------------------------------
 116
 117         st = rrdset_find_bytype("system", "softirqs");
 118         if(!st) {
 119                 st = rrdset_create("system", "softirqs", NULL, "softirqs", NULL, "System softirqs", "softirqs/s", 950, update_every, RRDSET_TYPE_STACKED);
 120
 121                 for(l = 0; l < lines ;l++) {
 122                         struct interrupt *irr = irrindex(irrs, l, cpus);
 123                         if(!irr->used) continue;
 124                         rrddim_add(st, irr->id, irr->name, 1, 1, RRDDIM_INCREMENTAL);
 125                 }
 126         }
 127         else rrdset_next(st);
 128
 129         for(l = 0; l < lines ;l++) {
 130                 struct interrupt *irr = irrindex(irrs, l, cpus);
 131                 if(!irr->used) continue;
 132                 rrddim_set(st, irr->id, irr->total);
 133         }
 134         rrdset_done(st);
 135
 136         if(do_per_core) {
 137                 int c;
 138
 139                 for(c = 0; c < cpus ; c++) {
 140                         char id[256+1];
 141                         snprintfz(id, 256, "cpu%d_softirqs", c);
 142
 143                         st = rrdset_find_bytype("cpu", id);
 144                         if(!st) {
 145                                 // find if everything is zero
 146                                 unsigned long long core_sum = 0 ;
 147                                 for(l = 0; l < lines ;l++) {
 148                                         struct interrupt *irr = irrindex(irrs, l, cpus);
 149                                         if(!irr->used) continue;
 150                                         core_sum += irr->value[c];
 151                                 }
 152                                 if(core_sum == 0) continue; // try next core
 153
 154                                 char name[256+1], title[256+1];
 155                                 snprintfz(name, 256, "cpu%d_softirqs", c);
 156                                 snprintfz(title, 256, "CPU%d softirqs", c);
 157                                 st = rrdset_create("cpu", id, name, "softirqs", "cpu.softirqs", title, "softirqs/s", 3000 + c, update_every, RRDSET_TYPE_STACKED);
 158
 159                                 for(l = 0; l < lines ;l++) {
 160                                         struct interrupt *irr = irrindex(irrs, l, cpus);
 161                                         if(!irr->used) continue;
 162                                         rrddim_add(st, irr->id, irr->name, 1, 1, RRDDIM_INCREMENTAL);
 163                                 }
 164                         }
 165                         else rrdset_next(st);
 166
 167                         for(l = 0; l < lines ;l++) {
 168                                 struct interrupt *irr = irrindex(irrs, l, cpus);
 169                                 if(!irr->used) continue;
 170                                 rrddim_set(st, irr->id, irr->value[c]);
 171                         }
 172                         rrdset_done(st);
 173                 }
 174         }
 175
 176         return 0;
 177 }