qemu

qht-bench.c (14073B)

---

 /*
  * Copyright (C) 2016, Emilio G. Cota <cota@braap.org>
  *
  * License: GNU GPL, version 2 or later.
  *   See the COPYING file in the top-level directory.
  */
 #include "qemu/osdep.h"
 #include "qemu/processor.h"
 #include "qemu/atomic.h"
 #include "qemu/qht.h"
 #include "qemu/rcu.h"
 #include "qemu/xxhash.h"
 #include "qemu/memalign.h"
 
 struct thread_stats {
     size_t rd;
     size_t not_rd;
     size_t in;
     size_t not_in;
     size_t rm;
     size_t not_rm;
     size_t rz;
     size_t not_rz;
 };
 
 struct thread_info {
     void (*func)(struct thread_info *);
     struct thread_stats stats;
     /*
      * Seed is in the range [1..UINT64_MAX], because the RNG requires
      * a non-zero seed.  To use, subtract 1 and compare against the
      * threshold with </>=.  This lets threshold = 0 never match (0% hit),
      * and threshold = UINT64_MAX always match (100% hit).
      */
     uint64_t seed;
     bool write_op; /* writes alternate between insertions and removals */
     bool resize_down;
 } QEMU_ALIGNED(64); /* avoid false sharing among threads */
 
 static struct qht ht;
 static QemuThread *rw_threads;
 
 #define DEFAULT_RANGE (4096)
 #define DEFAULT_QHT_N_ELEMS DEFAULT_RANGE
 
 static unsigned int duration = 1;
 static unsigned int n_rw_threads = 1;
 static unsigned long lookup_range = DEFAULT_RANGE;
 static unsigned long update_range = DEFAULT_RANGE;
 static size_t init_range = DEFAULT_RANGE;
 static size_t init_size = DEFAULT_RANGE;
 static size_t n_ready_threads;
 static long populate_offset;
 static long *keys;
 
 static size_t resize_min;
 static size_t resize_max;
 static struct thread_info *rz_info;
 static unsigned long resize_delay = 1000;
 static double resize_rate; /* 0.0 to 1.0 */
 static unsigned int n_rz_threads = 1;
 static QemuThread *rz_threads;
 static bool precompute_hash;
 
 static double update_rate; /* 0.0 to 1.0 */
 static uint64_t update_threshold;
 static uint64_t resize_threshold;
 
 static size_t qht_n_elems = DEFAULT_QHT_N_ELEMS;
 static int qht_mode;
 
 static bool test_start;
 static bool test_stop;
 
 static struct thread_info *rw_info;
 
 static const char commands_string[] =
     " -d = duration, in seconds\n"
     " -n = number of threads\n"
     "\n"
     " -o = offset at which keys start\n"
     " -p = precompute hashes\n"
     "\n"
     " -g = set -s,-k,-K,-l,-r to the same value\n"
     " -s = initial size hint\n"
     " -k = initial number of keys\n"
     " -K = initial range of keys (will be rounded up to pow2)\n"
     " -l = lookup range of keys (will be rounded up to pow2)\n"
     " -r = update range of keys (will be rounded up to pow2)\n"
     "\n"
     " -u = update rate (0.0 to 100.0), 50/50 split of insertions/removals\n"
     "\n"
     " -R = enable auto-resize\n"
     " -S = resize rate (0.0 to 100.0)\n"
     " -D = delay (in us) between potential resizes\n"
     " -N = number of resize threads";
 
 static void usage_complete(int argc, char *argv[])
 {
     fprintf(stderr, "Usage: %s [options]\n", argv[0]);
     fprintf(stderr, "options:\n%s\n", commands_string);
     exit(-1);
 }
 
 static bool is_equal(const void *ap, const void *bp)
 {
     const long *a = ap;
     const long *b = bp;
 
     return *a == *b;
 }
 
 static uint32_t h(unsigned long v)
 {
     return qemu_xxhash2(v);
 }
 
 static uint32_t hval(unsigned long v)
 {
     return v;
 }
 
 static uint32_t (*hfunc)(unsigned long v) = h;
 
 /*
  * From: https://en.wikipedia.org/wiki/Xorshift
  * This is faster than rand_r(), and gives us a wider range (RAND_MAX is only
  * guaranteed to be >= INT_MAX).
  */
 static uint64_t xorshift64star(uint64_t x)
 {
     x ^= x >> 12; /* a */
     x ^= x << 25; /* b */
     x ^= x >> 27; /* c */
     return x * UINT64_C(2685821657736338717);
 }
 
 static void do_rz(struct thread_info *info)
 {
     struct thread_stats *stats = &info->stats;
     uint64_t r = info->seed - 1;
 
     if (r < resize_threshold) {
         size_t size = info->resize_down ? resize_min : resize_max;
         bool resized;
 
         resized = qht_resize(&ht, size);
         info->resize_down = !info->resize_down;
 
         if (resized) {
             stats->rz++;
         } else {
             stats->not_rz++;
         }
     }
     g_usleep(resize_delay);
 }
 
 static void do_rw(struct thread_info *info)
 {
     struct thread_stats *stats = &info->stats;
     uint64_t r = info->seed - 1;
     uint32_t hash;
     long *p;
 
     if (r >= update_threshold) {
         bool read;
 
         p = &keys[r & (lookup_range - 1)];
         hash = hfunc(*p);
         read = qht_lookup(&ht, p, hash);
         if (read) {
             stats->rd++;
         } else {
             stats->not_rd++;
         }
     } else {
         p = &keys[r & (update_range - 1)];
         hash = hfunc(*p);
         if (info->write_op) {
             bool written = false;
 
             if (qht_lookup(&ht, p, hash) == NULL) {
                 written = qht_insert(&ht, p, hash, NULL);
             }
             if (written) {
                 stats->in++;
             } else {
                 stats->not_in++;
             }
         } else {
             bool removed = false;
 
             if (qht_lookup(&ht, p, hash)) {
                 removed = qht_remove(&ht, p, hash);
             }
             if (removed) {
                 stats->rm++;
             } else {
                 stats->not_rm++;
             }
         }
         info->write_op = !info->write_op;
     }
 }
 
 static void *thread_func(void *p)
 {
     struct thread_info *info = p;
 
     rcu_register_thread();
 
     qatomic_inc(&n_ready_threads);
     while (!qatomic_read(&test_start)) {
         cpu_relax();
     }
 
     rcu_read_lock();
     while (!qatomic_read(&test_stop)) {
         info->seed = xorshift64star(info->seed);
         info->func(info);
     }
     rcu_read_unlock();
 
     rcu_unregister_thread();
     return NULL;
 }
 
 /* sets everything except info->func */
 static void prepare_thread_info(struct thread_info *info, int i)
 {
     /* seed for the RNG; each thread should have a different one */
     info->seed = (i + 1) ^ time(NULL);
     /* the first update will be a write */
     info->write_op = true;
     /* the first resize will be down */
     info->resize_down = true;
 
     memset(&info->stats, 0, sizeof(info->stats));
 }
 
 static void
 th_create_n(QemuThread **threads, struct thread_info **infos, const char *name,
             void (*func)(struct thread_info *), int offset, int n)
 {
     struct thread_info *info;
     QemuThread *th;
     int i;
 
     th = g_malloc(sizeof(*th) * n);
     *threads = th;
 
     info = qemu_memalign(64, sizeof(*info) * n);
     *infos = info;
 
     for (i = 0; i < n; i++) {
         prepare_thread_info(&info[i], offset + i);
         info[i].func = func;
         qemu_thread_create(&th[i], name, thread_func, &info[i],
                            QEMU_THREAD_JOINABLE);
     }
 }
 
 static void create_threads(void)
 {
     th_create_n(&rw_threads, &rw_info, "rw", do_rw, 0, n_rw_threads);
     th_create_n(&rz_threads, &rz_info, "rz", do_rz, n_rw_threads, n_rz_threads);
 }
 
 static void pr_params(void)
 {
     printf("Parameters:\n");
     printf(" duration:          %d s\n", duration);
     printf(" # of threads:      %u\n", n_rw_threads);
     printf(" initial # of keys: %zu\n", init_size);
     printf(" initial size hint: %zu\n", qht_n_elems);
     printf(" auto-resize:       %s\n",
            qht_mode & QHT_MODE_AUTO_RESIZE ? "on" : "off");
     if (resize_rate) {
         printf(" resize_rate:       %f%%\n", resize_rate * 100.0);
         printf(" resize range:      %zu-%zu\n", resize_min, resize_max);
         printf(" # resize threads   %u\n", n_rz_threads);
     }
     printf(" update rate:       %f%%\n", update_rate * 100.0);
     printf(" offset:            %ld\n", populate_offset);
     printf(" initial key range: %zu\n", init_range);
     printf(" lookup range:      %lu\n", lookup_range);
     printf(" update range:      %lu\n", update_range);
 }
 
 static void do_threshold(double rate, uint64_t *threshold)
 {
     /*
      * For 0 <= rate <= 1, scale to fit in a uint64_t.
      *
      * Scale by 2**64, with a special case for 1.0.
      * The remainder of the possible values are scattered between 0
      * and 0xfffffffffffff800 (nextafter(0x1p64, 0)).
      *
      * Note that we cannot simply scale by UINT64_MAX, because that
      * value is not representable as an IEEE double value.
      *
      * If we scale by the next largest value, nextafter(0x1p64, 0),
      * then the remainder of the possible values are scattered between
      * 0 and 0xfffffffffffff000.  Which leaves us with a gap between
      * the final two inputs that is twice as large as any other.
      */
     if (rate == 1.0) {
         *threshold = UINT64_MAX;
     } else {
         *threshold = rate * 0x1p64;
     }
 }
 
 static void htable_init(void)
 {
     unsigned long n = MAX(init_range, update_range);
     uint64_t r = time(NULL);
     size_t retries = 0;
     size_t i;
 
     /* avoid allocating memory later by allocating all the keys now */
     keys = g_malloc(sizeof(*keys) * n);
     for (i = 0; i < n; i++) {
         long val = populate_offset + i;
 
         keys[i] = precompute_hash ? h(val) : hval(val);
     }
 
     /* some sanity checks */
     g_assert_cmpuint(lookup_range, <=, n);
 
     /* compute thresholds */
     do_threshold(update_rate, &update_threshold);
     do_threshold(resize_rate, &resize_threshold);
 
     if (resize_rate) {
         resize_min = n / 2;
         resize_max = n;
         assert(resize_min < resize_max);
     } else {
         n_rz_threads = 0;
     }
 
     /* initialize the hash table */
     qht_init(&ht, is_equal, qht_n_elems, qht_mode);
     assert(init_size <= init_range);
 
     pr_params();
 
     fprintf(stderr, "Initialization: populating %zu items...", init_size);
     for (i = 0; i < init_size; i++) {
         for (;;) {
             uint32_t hash;
             long *p;
 
             r = xorshift64star(r);
             p = &keys[r & (init_range - 1)];
             hash = hfunc(*p);
             if (qht_insert(&ht, p, hash, NULL)) {
                 break;
             }
             retries++;
         }
     }
     fprintf(stderr, " populated after %zu retries\n", retries);
 }
 
 static void add_stats(struct thread_stats *s, struct thread_info *info, int n)
 {
     int i;
 
     for (i = 0; i < n; i++) {
         struct thread_stats *stats = &info[i].stats;
 
         s->rd += stats->rd;
         s->not_rd += stats->not_rd;
 
         s->in += stats->in;
         s->not_in += stats->not_in;
 
         s->rm += stats->rm;
         s->not_rm += stats->not_rm;
 
         s->rz += stats->rz;
         s->not_rz += stats->not_rz;
     }
 }
 
 static void pr_stats(void)
 {
     struct thread_stats s = {};
     double tx;
 
     add_stats(&s, rw_info, n_rw_threads);
     add_stats(&s, rz_info, n_rz_threads);
 
     printf("Results:\n");
 
     if (resize_rate) {
         printf(" Resizes:           %zu (%.2f%% of %zu)\n",
                s.rz, (double)s.rz / (s.rz + s.not_rz) * 100, s.rz + s.not_rz);
     }
 
     printf(" Read:              %.2f M (%.2f%% of %.2fM)\n",
            (double)s.rd / 1e6,
            (double)s.rd / (s.rd + s.not_rd) * 100,
            (double)(s.rd + s.not_rd) / 1e6);
     printf(" Inserted:          %.2f M (%.2f%% of %.2fM)\n",
            (double)s.in / 1e6,
            (double)s.in / (s.in + s.not_in) * 100,
            (double)(s.in + s.not_in) / 1e6);
     printf(" Removed:           %.2f M (%.2f%% of %.2fM)\n",
            (double)s.rm / 1e6,
            (double)s.rm / (s.rm + s.not_rm) * 100,
            (double)(s.rm + s.not_rm) / 1e6);
 
     tx = (s.rd + s.not_rd + s.in + s.not_in + s.rm + s.not_rm) / 1e6 / duration;
     printf(" Throughput:        %.2f MT/s\n", tx);
     printf(" Throughput/thread: %.2f MT/s/thread\n", tx / n_rw_threads);
 }
 
 static void run_test(void)
 {
     int i;
 
     while (qatomic_read(&n_ready_threads) != n_rw_threads + n_rz_threads) {
         cpu_relax();
     }
 
     qatomic_set(&test_start, true);
     g_usleep(duration * G_USEC_PER_SEC);
     qatomic_set(&test_stop, true);
 
     for (i = 0; i < n_rw_threads; i++) {
         qemu_thread_join(&rw_threads[i]);
     }
     for (i = 0; i < n_rz_threads; i++) {
         qemu_thread_join(&rz_threads[i]);
     }
 }
 
 static void parse_args(int argc, char *argv[])
 {
     int c;
 
     for (;;) {
         c = getopt(argc, argv, "d:D:g:k:K:l:hn:N:o:pr:Rs:S:u:");
         if (c < 0) {
             break;
         }
         switch (c) {
         case 'd':
             duration = atoi(optarg);
             break;
         case 'D':
             resize_delay = atol(optarg);
             break;
         case 'g':
             init_range = pow2ceil(atol(optarg));
             lookup_range = pow2ceil(atol(optarg));
             update_range = pow2ceil(atol(optarg));
             qht_n_elems = atol(optarg);
             init_size = atol(optarg);
             break;
         case 'h':
             usage_complete(argc, argv);
             exit(0);
         case 'k':
             init_size = atol(optarg);
             break;
         case 'K':
             init_range = pow2ceil(atol(optarg));
             break;
         case 'l':
             lookup_range = pow2ceil(atol(optarg));
             break;
         case 'n':
             n_rw_threads = atoi(optarg);
             break;
         case 'N':
             n_rz_threads = atoi(optarg);
             break;
         case 'o':
             populate_offset = atol(optarg);
             break;
         case 'p':
             precompute_hash = true;
             hfunc = hval;
             break;
         case 'r':
             update_range = pow2ceil(atol(optarg));
             break;
         case 'R':
             qht_mode |= QHT_MODE_AUTO_RESIZE;
             break;
         case 's':
             qht_n_elems = atol(optarg);
             break;
         case 'S':
             resize_rate = atof(optarg) / 100.0;
             if (resize_rate > 1.0) {
                 resize_rate = 1.0;
             }
             break;
         case 'u':
             update_rate = atof(optarg) / 100.0;
             if (update_rate > 1.0) {
                 update_rate = 1.0;
             }
             break;
         }
     }
 }
 
 int main(int argc, char *argv[])
 {
     parse_args(argc, argv);
     htable_init();
     create_threads();
     run_test();
     pr_stats();
     return 0;
 }