xref: /openbmc/qemu/tests/bench/atomic_add-bench.c (revision 50243407)
1 #include "qemu/osdep.h"
2 #include "qemu/thread.h"
3 #include "qemu/host-utils.h"
4 #include "qemu/processor.h"
5 
6 struct thread_info {
7     uint64_t r;
8 } QEMU_ALIGNED(64);
9 
10 struct count {
11     QemuMutex lock;
12     unsigned long val;
13 } QEMU_ALIGNED(64);
14 
15 static QemuThread *threads;
16 static struct thread_info *th_info;
17 static unsigned int n_threads = 1;
18 static unsigned int n_ready_threads;
19 static struct count *counts;
20 static unsigned int duration = 1;
21 static unsigned int range = 1024;
22 static bool use_mutex;
23 static bool test_start;
24 static bool test_stop;
25 
26 static const char commands_string[] =
27     " -n = number of threads\n"
28     " -m = use mutexes instead of atomic increments\n"
29     " -p = enable sync profiler\n"
30     " -d = duration in seconds\n"
31     " -r = range (will be rounded up to pow2)";
32 
33 static void usage_complete(char *argv[])
34 {
35     fprintf(stderr, "Usage: %s [options]\n", argv[0]);
36     fprintf(stderr, "options:\n%s\n", commands_string);
37 }
38 
39 /*
40  * From: https://en.wikipedia.org/wiki/Xorshift
41  * This is faster than rand_r(), and gives us a wider range (RAND_MAX is only
42  * guaranteed to be >= INT_MAX).
43  */
44 static uint64_t xorshift64star(uint64_t x)
45 {
46     x ^= x >> 12; /* a */
47     x ^= x << 25; /* b */
48     x ^= x >> 27; /* c */
49     return x * UINT64_C(2685821657736338717);
50 }
51 
52 static void *thread_func(void *arg)
53 {
54     struct thread_info *info = arg;
55 
56     qatomic_inc(&n_ready_threads);
57     while (!qatomic_read(&test_start)) {
58         cpu_relax();
59     }
60 
61     while (!qatomic_read(&test_stop)) {
62         unsigned int index;
63 
64         info->r = xorshift64star(info->r);
65         index = info->r & (range - 1);
66         if (use_mutex) {
67             qemu_mutex_lock(&counts[index].lock);
68             counts[index].val += 1;
69             qemu_mutex_unlock(&counts[index].lock);
70         } else {
71             qatomic_inc(&counts[index].val);
72         }
73     }
74     return NULL;
75 }
76 
77 static void run_test(void)
78 {
79     unsigned int i;
80 
81     while (qatomic_read(&n_ready_threads) != n_threads) {
82         cpu_relax();
83     }
84 
85     qatomic_set(&test_start, true);
86     g_usleep(duration * G_USEC_PER_SEC);
87     qatomic_set(&test_stop, true);
88 
89     for (i = 0; i < n_threads; i++) {
90         qemu_thread_join(&threads[i]);
91     }
92 }
93 
94 static void create_threads(void)
95 {
96     unsigned int i;
97 
98     threads = g_new(QemuThread, n_threads);
99     th_info = g_new(struct thread_info, n_threads);
100     counts = qemu_memalign(64, sizeof(*counts) * range);
101     memset(counts, 0, sizeof(*counts) * range);
102     for (i = 0; i < range; i++) {
103         qemu_mutex_init(&counts[i].lock);
104     }
105 
106     for (i = 0; i < n_threads; i++) {
107         struct thread_info *info = &th_info[i];
108 
109         info->r = (i + 1) ^ time(NULL);
110         qemu_thread_create(&threads[i], NULL, thread_func, info,
111                            QEMU_THREAD_JOINABLE);
112     }
113 }
114 
115 static void pr_params(void)
116 {
117     printf("Parameters:\n");
118     printf(" # of threads:      %u\n", n_threads);
119     printf(" duration:          %u\n", duration);
120     printf(" ops' range:        %u\n", range);
121 }
122 
123 static void pr_stats(void)
124 {
125     unsigned long long val = 0;
126     unsigned int i;
127     double tx;
128 
129     for (i = 0; i < range; i++) {
130         val += counts[i].val;
131     }
132     tx = val / duration / 1e6;
133 
134     printf("Results:\n");
135     printf("Duration:            %u s\n", duration);
136     printf(" Throughput:         %.2f Mops/s\n", tx);
137     printf(" Throughput/thread:  %.2f Mops/s/thread\n", tx / n_threads);
138 }
139 
140 static void parse_args(int argc, char *argv[])
141 {
142     int c;
143 
144     for (;;) {
145         c = getopt(argc, argv, "hd:n:mpr:");
146         if (c < 0) {
147             break;
148         }
149         switch (c) {
150         case 'h':
151             usage_complete(argv);
152             exit(0);
153         case 'd':
154             duration = atoi(optarg);
155             break;
156         case 'n':
157             n_threads = atoi(optarg);
158             break;
159         case 'm':
160             use_mutex = true;
161             break;
162         case 'p':
163             qsp_enable();
164             break;
165         case 'r':
166             range = pow2ceil(atoi(optarg));
167             break;
168         }
169     }
170 }
171 
172 int main(int argc, char *argv[])
173 {
174     parse_args(argc, argv);
175     pr_params();
176     create_threads();
177     run_test();
178     pr_stats();
179     return 0;
180 }
181