t/helper/test-lazy-init-name-hash.c

   1 #include "cache.h"
   2 #include "parse-options.h"
   3
   4 static int single;
   5 static int multi;
   6 static int count = 1;
   7 static int dump;
   8 static int perf;
   9 static int analyze;
  10 static int analyze_step;
  11
  12 /*
  13  * Dump the contents of the "dir" and "name" hash tables to stdout.
  14  * If you sort the result, you can compare it with the other type
  15  * mode and verify that both single and multi produce the same set.
  16  */
  17 static void dump_run(void)
  18 {
  19         struct hashmap_iter iter_dir;
  20         struct hashmap_iter iter_cache;
  21
  22         /* Stolen from name-hash.c */
  23         struct dir_entry {
  24                 struct hashmap_entry ent;
  25                 struct dir_entry *parent;
  26                 int nr;
  27                 unsigned int namelen;
  28                 char name[FLEX_ARRAY];
  29         };
  30
  31         struct dir_entry *dir;
  32         struct cache_entry *ce;
  33
  34         read_cache();
  35         if (single) {
  36                 test_lazy_init_name_hash(&the_index, 0);
  37         } else {
  38                 int nr_threads_used = test_lazy_init_name_hash(&the_index, 1);
  39                 if (!nr_threads_used)
  40                         die("non-threaded code path used");
  41         }
  42
  43         dir = hashmap_iter_first(&the_index.dir_hash, &iter_dir);
  44         while (dir) {
  45                 printf("dir %08x %7d %s\n", dir->ent.hash, dir->nr, dir->name);
  46                 dir = hashmap_iter_next(&iter_dir);
  47         }
  48
  49         ce = hashmap_iter_first(&the_index.name_hash, &iter_cache);
  50         while (ce) {
  51                 printf("name %08x %s\n", ce->ent.hash, ce->name);
  52                 ce = hashmap_iter_next(&iter_cache);
  53         }
  54
  55         discard_cache();
  56 }
  57
  58 /*
  59  * Run the single or multi threaded version "count" times and
  60  * report on the time taken.
  61  */
  62 static uint64_t time_runs(int try_threaded)
  63 {
  64         uint64_t t0, t1, t2;
  65         uint64_t sum = 0;
  66         uint64_t avg;
  67         int nr_threads_used;
  68         int i;
  69
  70         for (i = 0; i < count; i++) {
  71                 t0 = getnanotime();
  72                 read_cache();
  73                 t1 = getnanotime();
  74                 nr_threads_used = test_lazy_init_name_hash(&the_index, try_threaded);
  75                 t2 = getnanotime();
  76
  77                 sum += (t2 - t1);
  78
  79                 if (try_threaded && !nr_threads_used)
  80                         die("non-threaded code path used");
  81
  82                 if (nr_threads_used)
  83                         printf("%f %f %d multi %d\n",
  84                                    ((double)(t1 - t0))/1000000000,
  85                                    ((double)(t2 - t1))/1000000000,
  86                                    the_index.cache_nr,
  87                                    nr_threads_used);
  88                 else
  89                         printf("%f %f %d single\n",
  90                                    ((double)(t1 - t0))/1000000000,
  91                                    ((double)(t2 - t1))/1000000000,
  92                                    the_index.cache_nr);
  93                 fflush(stdout);
  94
  95                 discard_cache();
  96         }
  97
  98         avg = sum / count;
  99         if (count > 1)
 100                 printf("avg %f %s\n",
 101                            (double)avg/1000000000,
 102                            (try_threaded) ? "multi" : "single");
 103
 104         return avg;
 105 }
 106
 107 /*
 108  * Try a series of runs varying the "istate->cache_nr" and
 109  * try to find a good value for the multi-threaded criteria.
 110  */
 111 static void analyze_run(void)
 112 {
 113         uint64_t t1s, t1m, t2s, t2m;
 114         int cache_nr_limit;
 115         int nr_threads_used;
 116         int i;
 117         int nr;
 118
 119         read_cache();
 120         cache_nr_limit = the_index.cache_nr;
 121         discard_cache();
 122
 123         nr = analyze;
 124         while (1) {
 125                 uint64_t sum_single = 0;
 126                 uint64_t sum_multi = 0;
 127                 uint64_t avg_single;
 128                 uint64_t avg_multi;
 129
 130                 if (nr > cache_nr_limit)
 131                         nr = cache_nr_limit;
 132
 133                 for (i = 0; i < count; i++) {
 134                         read_cache();
 135                         the_index.cache_nr = nr; /* cheap truncate of index */
 136                         t1s = getnanotime();
 137                         test_lazy_init_name_hash(&the_index, 0);
 138                         t2s = getnanotime();
 139                         sum_single += (t2s - t1s);
 140                         the_index.cache_nr = cache_nr_limit;
 141                         discard_cache();
 142
 143                         read_cache();
 144                         the_index.cache_nr = nr; /* cheap truncate of index */
 145                         t1m = getnanotime();
 146                         nr_threads_used = test_lazy_init_name_hash(&the_index, 1);
 147                         t2m = getnanotime();
 148                         sum_multi += (t2m - t1m);
 149                         the_index.cache_nr = cache_nr_limit;
 150                         discard_cache();
 151
 152                         if (!nr_threads_used)
 153                                 printf("    [size %8d] [single %f]   non-threaded code path used\n",
 154                                            nr, ((double)(t2s - t1s))/1000000000);
 155                         else
 156                                 printf("    [size %8d] [single %f] %c [multi %f %d]\n",
 157                                            nr,
 158                                            ((double)(t2s - t1s))/1000000000,
 159                                            (((t2s - t1s) < (t2m - t1m)) ? '<' : '>'),
 160                                            ((double)(t2m - t1m))/1000000000,
 161                                            nr_threads_used);
 162                         fflush(stdout);
 163                 }
 164                 if (count > 1) {
 165                         avg_single = sum_single / count;
 166                         avg_multi = sum_multi / count;
 167                         if (!nr_threads_used)
 168                                 printf("avg [size %8d] [single %f]\n",
 169                                            nr,
 170                                            (double)avg_single/1000000000);
 171                         else
 172                                 printf("avg [size %8d] [single %f] %c [multi %f %d]\n",
 173                                            nr,
 174                                            (double)avg_single/1000000000,
 175                                            (avg_single < avg_multi ? '<' : '>'),
 176                                            (double)avg_multi/1000000000,
 177                                            nr_threads_used);
 178                         fflush(stdout);
 179                 }
 180
 181                 if (nr >= cache_nr_limit)
 182                         return;
 183                 nr += analyze_step;
 184         }
 185 }
 186
 187 int cmd_main(int argc, const char **argv)
 188 {
 189         const char *usage[] = {
 190                 "test-lazy-init-name-hash -d (-s | -m)",
 191                 "test-lazy-init-name-hash -p [-c c]",
 192                 "test-lazy-init-name-hash -a a [--step s] [-c c]",
 193                 "test-lazy-init-name-hash (-s | -m) [-c c]",
 194                 "test-lazy-init-name-hash -s -m [-c c]",
 195                 NULL
 196         };
 197         struct option options[] = {
 198                 OPT_BOOL('s', "single", &single, "run single-threaded code"),
 199                 OPT_BOOL('m', "multi", &multi, "run multi-threaded code"),
 200                 OPT_INTEGER('c', "count", &count, "number of passes"),
 201                 OPT_BOOL('d', "dump", &dump, "dump hash tables"),
 202                 OPT_BOOL('p', "perf", &perf, "compare single vs multi"),
 203                 OPT_INTEGER('a', "analyze", &analyze, "analyze different multi sizes"),
 204                 OPT_INTEGER(0, "step", &analyze_step, "analyze step factor"),
 205                 OPT_END(),
 206         };
 207         const char *prefix;
 208         uint64_t avg_single, avg_multi;
 209
 210         prefix = setup_git_directory();
 211
 212         argc = parse_options(argc, argv, prefix, options, usage, 0);
 213
 214         /*
 215          * istate->dir_hash is only created when ignore_case is set.
 216          */
 217         ignore_case = 1;
 218
 219         if (dump) {
 220                 if (perf || analyze > 0)
 221                         die("cannot combine dump, perf, or analyze");
 222                 if (count > 1)
 223                         die("count not valid with dump");
 224                 if (single && multi)
 225                         die("cannot use both single and multi with dump");
 226                 if (!single && !multi)
 227                         die("dump requires either single or multi");
 228                 dump_run();
 229                 return 0;
 230         }
 231
 232         if (perf) {
 233                 if (analyze > 0)
 234                         die("cannot combine dump, perf, or analyze");
 235                 if (single || multi)
 236                         die("cannot use single or multi with perf");
 237                 avg_single = time_runs(0);
 238                 avg_multi = time_runs(1);
 239                 if (avg_multi > avg_single)
 240                         die("multi is slower");
 241                 return 0;
 242         }
 243
 244         if (analyze) {
 245                 if (analyze < 500)
 246                         die("analyze must be at least 500");
 247                 if (!analyze_step)
 248                         analyze_step = analyze;
 249                 if (single || multi)
 250                         die("cannot use single or multi with analyze");
 251                 analyze_run();
 252                 return 0;
 253         }
 254
 255         if (!single && !multi)
 256                 die("require either -s or -m or both");
 257
 258         if (single)
 259                 time_runs(0);
 260         if (multi)
 261                 time_runs(1);
 262
 263         return 0;
 264 }