tests/qht-bench.c

   1 /*
   2  * Copyright (C) 2016, Emilio G. Cota <cota@braap.org>
   3  *
   4  * License: GNU GPL, version 2 or later.
   5  *   See the COPYING file in the top-level directory.
   6  */
   7 #include "qemu/osdep.h"
   8 #include "qemu/processor.h"
   9 #include "qemu/atomic.h"
  10 #include "qemu/qht.h"
  11 #include "qemu/rcu.h"
  12 #include "qemu/xxhash.h"
  13
  14 struct thread_stats {
  15     size_t rd;
  16     size_t not_rd;
  17     size_t in;
  18     size_t not_in;
  19     size_t rm;
  20     size_t not_rm;
  21     size_t rz;
  22     size_t not_rz;
  23 };
  24
  25 struct thread_info {
  26     void (*func)(struct thread_info *);
  27     struct thread_stats stats;
  28     uint64_t r;
  29     bool write_op; /* writes alternate between insertions and removals */
  30     bool resize_down;
  31 } QEMU_ALIGNED(64); /* avoid false sharing among threads */
  32
  33 static struct qht ht;
  34 static QemuThread *rw_threads;
  35
  36 #define DEFAULT_RANGE (4096)
  37 #define DEFAULT_QHT_N_ELEMS DEFAULT_RANGE
  38
  39 static unsigned int duration = 1;
  40 static unsigned int n_rw_threads = 1;
  41 static unsigned long lookup_range = DEFAULT_RANGE;
  42 static unsigned long update_range = DEFAULT_RANGE;
  43 static size_t init_range = DEFAULT_RANGE;
  44 static size_t init_size = DEFAULT_RANGE;
  45 static size_t n_ready_threads;
  46 static long populate_offset;
  47 static long *keys;
  48
  49 static size_t resize_min;
  50 static size_t resize_max;
  51 static struct thread_info *rz_info;
  52 static unsigned long resize_delay = 1000;
  53 static double resize_rate; /* 0.0 to 1.0 */
  54 static unsigned int n_rz_threads = 1;
  55 static QemuThread *rz_threads;
  56 static bool precompute_hash;
  57
  58 static double update_rate; /* 0.0 to 1.0 */
  59 static uint64_t update_threshold;
  60 static uint64_t resize_threshold;
  61
  62 static size_t qht_n_elems = DEFAULT_QHT_N_ELEMS;
  63 static int qht_mode;
  64
  65 static bool test_start;
  66 static bool test_stop;
  67
  68 static struct thread_info *rw_info;
  69
  70 static const char commands_string[] =
  71     " -d = duration, in seconds\n"
  72     " -n = number of threads\n"
  73     "\n"
  74     " -o = offset at which keys start\n"
  75     " -p = precompute hashes\n"
  76     "\n"
  77     " -g = set -s,-k,-K,-l,-r to the same value\n"
  78     " -s = initial size hint\n"
  79     " -k = initial number of keys\n"
  80     " -K = initial range of keys (will be rounded up to pow2)\n"
  81     " -l = lookup range of keys (will be rounded up to pow2)\n"
  82     " -r = update range of keys (will be rounded up to pow2)\n"
  83     "\n"
  84     " -u = update rate (0.0 to 100.0), 50/50 split of insertions/removals\n"
  85     "\n"
  86     " -R = enable auto-resize\n"
  87     " -S = resize rate (0.0 to 100.0)\n"
  88     " -D = delay (in us) between potential resizes\n"
  89     " -N = number of resize threads";
  90
  91 static void usage_complete(int argc, char *argv[])
  92 {
  93     fprintf(stderr, "Usage: %s [options]\n", argv[0]);
  94     fprintf(stderr, "options:\n%s\n", commands_string);
  95     exit(-1);
  96 }
  97
  98 static bool is_equal(const void *ap, const void *bp)
  99 {
 100     const long *a = ap;
 101     const long *b = bp;
 102
 103     return *a == *b;
 104 }
 105
 106 static uint32_t h(unsigned long v)
 107 {
 108     return qemu_xxhash2(v);
 109 }
 110
 111 static uint32_t hval(unsigned long v)
 112 {
 113     return v;
 114 }
 115
 116 static uint32_t (*hfunc)(unsigned long v) = h;
 117
 118 /*
 119  * From: https://en.wikipedia.org/wiki/Xorshift
 120  * This is faster than rand_r(), and gives us a wider range (RAND_MAX is only
 121  * guaranteed to be >= INT_MAX).
 122  */
 123 static uint64_t xorshift64star(uint64_t x)
 124 {
 125     x ^= x >> 12; /* a */
 126     x ^= x << 25; /* b */
 127     x ^= x >> 27; /* c */
 128     return x * UINT64_C(2685821657736338717);
 129 }
 130
 131 static void do_rz(struct thread_info *info)
 132 {
 133     struct thread_stats *stats = &info->stats;
 134
 135     if (info->r < resize_threshold) {
 136         size_t size = info->resize_down ? resize_min : resize_max;
 137         bool resized;
 138
 139         resized = qht_resize(&ht, size);
 140         info->resize_down = !info->resize_down;
 141
 142         if (resized) {
 143             stats->rz++;
 144         } else {
 145             stats->not_rz++;
 146         }
 147     }
 148     g_usleep(resize_delay);
 149 }
 150
 151 static void do_rw(struct thread_info *info)
 152 {
 153     struct thread_stats *stats = &info->stats;
 154     uint32_t hash;
 155     long *p;
 156
 157     if (info->r >= update_threshold) {
 158         bool read;
 159
 160         p = &keys[info->r & (lookup_range - 1)];
 161         hash = hfunc(*p);
 162         read = qht_lookup(&ht, p, hash);
 163         if (read) {
 164             stats->rd++;
 165         } else {
 166             stats->not_rd++;
 167         }
 168     } else {
 169         p = &keys[info->r & (update_range - 1)];
 170         hash = hfunc(*p);
 171         if (info->write_op) {
 172             bool written = false;
 173
 174             if (qht_lookup(&ht, p, hash) == NULL) {
 175                 written = qht_insert(&ht, p, hash, NULL);
 176             }
 177             if (written) {
 178                 stats->in++;
 179             } else {
 180                 stats->not_in++;
 181             }
 182         } else {
 183             bool removed = false;
 184
 185             if (qht_lookup(&ht, p, hash)) {
 186                 removed = qht_remove(&ht, p, hash);
 187             }
 188             if (removed) {
 189                 stats->rm++;
 190             } else {
 191                 stats->not_rm++;
 192             }
 193         }
 194         info->write_op = !info->write_op;
 195     }
 196 }
 197
 198 static void *thread_func(void *p)
 199 {
 200     struct thread_info *info = p;
 201
 202     rcu_register_thread();
 203
 204     atomic_inc(&n_ready_threads);
 205     while (!atomic_read(&test_start)) {
 206         cpu_relax();
 207     }
 208
 209     rcu_read_lock();
 210     while (!atomic_read(&test_stop)) {
 211         info->r = xorshift64star(info->r);
 212         info->func(info);
 213     }
 214     rcu_read_unlock();
 215
 216     rcu_unregister_thread();
 217     return NULL;
 218 }
 219
 220 /* sets everything except info->func */
 221 static void prepare_thread_info(struct thread_info *info, int i)
 222 {
 223     /* seed for the RNG; each thread should have a different one */
 224     info->r = (i + 1) ^ time(NULL);
 225     /* the first update will be a write */
 226     info->write_op = true;
 227     /* the first resize will be down */
 228     info->resize_down = true;
 229
 230     memset(&info->stats, 0, sizeof(info->stats));
 231 }
 232
 233 static void
 234 th_create_n(QemuThread **threads, struct thread_info **infos, const char *name,
 235             void (*func)(struct thread_info *), int offset, int n)
 236 {
 237     struct thread_info *info;
 238     QemuThread *th;
 239     int i;
 240
 241     th = g_malloc(sizeof(*th) * n);
 242     *threads = th;
 243
 244     info = qemu_memalign(64, sizeof(*info) * n);
 245     *infos = info;
 246
 247     for (i = 0; i < n; i++) {
 248         prepare_thread_info(&info[i], offset + i);
 249         info[i].func = func;
 250         qemu_thread_create(&th[i], name, thread_func, &info[i],
 251                            QEMU_THREAD_JOINABLE);
 252     }
 253 }
 254
 255 static void create_threads(void)
 256 {
 257     th_create_n(&rw_threads, &rw_info, "rw", do_rw, 0, n_rw_threads);
 258     th_create_n(&rz_threads, &rz_info, "rz", do_rz, n_rw_threads, n_rz_threads);
 259 }
 260
 261 static void pr_params(void)
 262 {
 263     printf("Parameters:\n");
 264     printf(" duration:          %d s\n", duration);
 265     printf(" # of threads:      %u\n", n_rw_threads);
 266     printf(" initial # of keys: %zu\n", init_size);
 267     printf(" initial size hint: %zu\n", qht_n_elems);
 268     printf(" auto-resize:       %s\n",
 269            qht_mode & QHT_MODE_AUTO_RESIZE ? "on" : "off");
 270     if (resize_rate) {
 271         printf(" resize_rate:       %f%%\n", resize_rate * 100.0);
 272         printf(" resize range:      %zu-%zu\n", resize_min, resize_max);
 273         printf(" # resize threads   %u\n", n_rz_threads);
 274     }
 275     printf(" update rate:       %f%%\n", update_rate * 100.0);
 276     printf(" offset:            %ld\n", populate_offset);
 277     printf(" initial key range: %zu\n", init_range);
 278     printf(" lookup range:      %lu\n", lookup_range);
 279     printf(" update range:      %lu\n", update_range);
 280 }
 281
 282 static void do_threshold(double rate, uint64_t *threshold)
 283 {
 284     if (rate == 1.0) {
 285         *threshold = UINT64_MAX;
 286     } else {
 287         *threshold = rate * UINT64_MAX;
 288     }
 289 }
 290
 291 static void htable_init(void)
 292 {
 293     unsigned long n = MAX(init_range, update_range);
 294     uint64_t r = time(NULL);
 295     size_t retries = 0;
 296     size_t i;
 297
 298     /* avoid allocating memory later by allocating all the keys now */
 299     keys = g_malloc(sizeof(*keys) * n);
 300     for (i = 0; i < n; i++) {
 301         long val = populate_offset + i;
 302
 303         keys[i] = precompute_hash ? h(val) : hval(val);
 304     }
 305
 306     /* some sanity checks */
 307     g_assert_cmpuint(lookup_range, <=, n);
 308
 309     /* compute thresholds */
 310     do_threshold(update_rate, &update_threshold);
 311     do_threshold(resize_rate, &resize_threshold);
 312
 313     if (resize_rate) {
 314         resize_min = n / 2;
 315         resize_max = n;
 316         assert(resize_min < resize_max);
 317     } else {
 318         n_rz_threads = 0;
 319     }
 320
 321     /* initialize the hash table */
 322     qht_init(&ht, is_equal, qht_n_elems, qht_mode);
 323     assert(init_size <= init_range);
 324
 325     pr_params();
 326
 327     fprintf(stderr, "Initialization: populating %zu items...", init_size);
 328     for (i = 0; i < init_size; i++) {
 329         for (;;) {
 330             uint32_t hash;
 331             long *p;
 332
 333             r = xorshift64star(r);
 334             p = &keys[r & (init_range - 1)];
 335             hash = hfunc(*p);
 336             if (qht_insert(&ht, p, hash, NULL)) {
 337                 break;
 338             }
 339             retries++;
 340         }
 341     }
 342     fprintf(stderr, " populated after %zu retries\n", retries);
 343 }
 344
 345 static void add_stats(struct thread_stats *s, struct thread_info *info, int n)
 346 {
 347     int i;
 348
 349     for (i = 0; i < n; i++) {
 350         struct thread_stats *stats = &info[i].stats;
 351
 352         s->rd += stats->rd;
 353         s->not_rd += stats->not_rd;
 354
 355         s->in += stats->in;
 356         s->not_in += stats->not_in;
 357
 358         s->rm += stats->rm;
 359         s->not_rm += stats->not_rm;
 360
 361         s->rz += stats->rz;
 362         s->not_rz += stats->not_rz;
 363     }
 364 }
 365
 366 static void pr_stats(void)
 367 {
 368     struct thread_stats s = {};
 369     double tx;
 370
 371     add_stats(&s, rw_info, n_rw_threads);
 372     add_stats(&s, rz_info, n_rz_threads);
 373
 374     printf("Results:\n");
 375
 376     if (resize_rate) {
 377         printf(" Resizes:           %zu (%.2f%% of %zu)\n",
 378                s.rz, (double)s.rz / (s.rz + s.not_rz) * 100, s.rz + s.not_rz);
 379     }
 380
 381     printf(" Read:              %.2f M (%.2f%% of %.2fM)\n",
 382            (double)s.rd / 1e6,
 383            (double)s.rd / (s.rd + s.not_rd) * 100,
 384            (double)(s.rd + s.not_rd) / 1e6);
 385     printf(" Inserted:          %.2f M (%.2f%% of %.2fM)\n",
 386            (double)s.in / 1e6,
 387            (double)s.in / (s.in + s.not_in) * 100,
 388            (double)(s.in + s.not_in) / 1e6);
 389     printf(" Removed:           %.2f M (%.2f%% of %.2fM)\n",
 390            (double)s.rm / 1e6,
 391            (double)s.rm / (s.rm + s.not_rm) * 100,
 392            (double)(s.rm + s.not_rm) / 1e6);
 393
 394     tx = (s.rd + s.not_rd + s.in + s.not_in + s.rm + s.not_rm) / 1e6 / duration;
 395     printf(" Throughput:        %.2f MT/s\n", tx);
 396     printf(" Throughput/thread: %.2f MT/s/thread\n", tx / n_rw_threads);
 397 }
 398
 399 static void run_test(void)
 400 {
 401     int i;
 402
 403     while (atomic_read(&n_ready_threads) != n_rw_threads + n_rz_threads) {
 404         cpu_relax();
 405     }
 406
 407     atomic_set(&test_start, true);
 408     g_usleep(duration * G_USEC_PER_SEC);
 409     atomic_set(&test_stop, true);
 410
 411     for (i = 0; i < n_rw_threads; i++) {
 412         qemu_thread_join(&rw_threads[i]);
 413     }
 414     for (i = 0; i < n_rz_threads; i++) {
 415         qemu_thread_join(&rz_threads[i]);
 416     }
 417 }
 418
 419 static void parse_args(int argc, char *argv[])
 420 {
 421     int c;
 422
 423     for (;;) {
 424         c = getopt(argc, argv, "d:D:g:k:K:l:hn:N:o:pr:Rs:S:u:");
 425         if (c < 0) {
 426             break;
 427         }
 428         switch (c) {
 429         case 'd':
 430             duration = atoi(optarg);
 431             break;
 432         case 'D':
 433             resize_delay = atol(optarg);
 434             break;
 435         case 'g':
 436             init_range = pow2ceil(atol(optarg));
 437             lookup_range = pow2ceil(atol(optarg));
 438             update_range = pow2ceil(atol(optarg));
 439             qht_n_elems = atol(optarg);
 440             init_size = atol(optarg);
 441             break;
 442         case 'h':
 443             usage_complete(argc, argv);
 444             exit(0);
 445         case 'k':
 446             init_size = atol(optarg);
 447             break;
 448         case 'K':
 449             init_range = pow2ceil(atol(optarg));
 450             break;
 451         case 'l':
 452             lookup_range = pow2ceil(atol(optarg));
 453             break;
 454         case 'n':
 455             n_rw_threads = atoi(optarg);
 456             break;
 457         case 'N':
 458             n_rz_threads = atoi(optarg);
 459             break;
 460         case 'o':
 461             populate_offset = atol(optarg);
 462             break;
 463         case 'p':
 464             precompute_hash = true;
 465             hfunc = hval;
 466             break;
 467         case 'r':
 468             update_range = pow2ceil(atol(optarg));
 469             break;
 470         case 'R':
 471             qht_mode |= QHT_MODE_AUTO_RESIZE;
 472             break;
 473         case 's':
 474             qht_n_elems = atol(optarg);
 475             break;
 476         case 'S':
 477             resize_rate = atof(optarg) / 100.0;
 478             if (resize_rate > 1.0) {
 479                 resize_rate = 1.0;
 480             }
 481             break;
 482         case 'u':
 483             update_rate = atof(optarg) / 100.0;
 484             if (update_rate > 1.0) {
 485                 update_rate = 1.0;
 486             }
 487             break;
 488         }
 489     }
 490 }
 491
 492 int main(int argc, char *argv[])
 493 {
 494     parse_args(argc, argv);
 495     htable_init();
 496     create_threads();
 497     run_test();
 498     pr_stats();
 499     return 0;
 500 }