1 /*
2 *
3 * Copyright 2015 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19 /* Test gpr per-cpu support:
20 gpr_cpu_num_cores()
21 gpr_cpu_current_cpu()
22 */
23
24 #include <grpc/support/cpu.h>
25
26 #include <stdio.h>
27 #include <string.h>
28
29 #include <grpc/support/alloc.h>
30 #include <grpc/support/log.h>
31 #include <grpc/support/sync.h>
32 #include <grpc/support/time.h>
33
34 #include "src/core/lib/gprpp/thd.h"
35 #include "test/core/util/test_config.h"
36
37 /* Test structure is essentially:
38 1) Figure out how many cores are present on the test system
39 2) Create 3 times that many threads
40 3) Have each thread do some amount of work (basically want to
41 gaurantee that all threads are running at once, and enough of them
42 to run on all cores).
43 4) Each thread checks what core it is running on, and marks that core
44 as "used" in the test.
45 5) Count number of "used" cores.
46
47 The test will fail if:
48 1) gpr_cpu_num_cores() == 0
49 2) Any result from gpr_cpu_current_cpu() >= gpr_cpu_num_cores()
50 3) Ideally, we would fail if not all cores were seen as used. Unfortunately,
51 this is only probabilistically true, and depends on the OS, it's
52 scheduler, etc. So we just print out an indication of how many were seen;
53 hopefully developers can use this to sanity check their system.
54 */
55
56 /* Status shared across threads */
57 struct cpu_test {
58 gpr_mu mu;
59 int nthreads;
60 uint32_t ncores;
61 int is_done;
62 gpr_cv done_cv;
63 int* used; /* is this core used? */
64 unsigned r; /* random number */
65 };
66
worker_thread(void * arg)67 static void worker_thread(void* arg) {
68 struct cpu_test* ct = static_cast<struct cpu_test*>(arg);
69 uint32_t cpu;
70 unsigned r = 12345678;
71 unsigned i, j;
72 /* Avoid repetitive division calculations */
73 int64_t max_i = 1000 / grpc_test_slowdown_factor();
74 int64_t max_j = 1000 / grpc_test_slowdown_factor();
75 for (i = 0; i < max_i; i++) {
76 /* run for a bit - just calculate something random. */
77 for (j = 0; j < max_j; j++) {
78 r = (r * 17) & ((r - i) | (r * i));
79 }
80 cpu = gpr_cpu_current_cpu();
81 GPR_ASSERT(cpu < ct->ncores);
82 gpr_mu_lock(&ct->mu);
83 ct->used[cpu] = 1;
84 for (j = 0; j < ct->ncores; j++) {
85 if (!ct->used[j]) break;
86 }
87 gpr_mu_unlock(&ct->mu);
88 if (j == ct->ncores) {
89 break; /* all cpus have been used - no further use in running this test */
90 }
91 }
92 gpr_mu_lock(&ct->mu);
93 ct->r = r; /* make it look like we care about r's value... */
94 ct->nthreads--;
95 if (ct->nthreads == 0) {
96 ct->is_done = 1;
97 gpr_cv_signal(&ct->done_cv);
98 }
99 gpr_mu_unlock(&ct->mu);
100 }
101
cpu_test(void)102 static void cpu_test(void) {
103 uint32_t i;
104 int cores_seen = 0;
105 struct cpu_test ct;
106 ct.ncores = gpr_cpu_num_cores();
107 GPR_ASSERT(ct.ncores > 0);
108 ct.nthreads = static_cast<int>(ct.ncores) * 3;
109 ct.used = static_cast<int*>(gpr_malloc(ct.ncores * sizeof(int)));
110 memset(ct.used, 0, ct.ncores * sizeof(int));
111 gpr_mu_init(&ct.mu);
112 gpr_cv_init(&ct.done_cv);
113 ct.is_done = 0;
114
115 uint32_t nthreads = ct.ncores * 3;
116 grpc_core::Thread* thd =
117 static_cast<grpc_core::Thread*>(gpr_malloc(sizeof(*thd) * nthreads));
118
119 for (i = 0; i < nthreads; i++) {
120 thd[i] = grpc_core::Thread("grpc_cpu_test", &worker_thread, &ct);
121 thd[i].Start();
122 }
123 gpr_mu_lock(&ct.mu);
124 while (!ct.is_done) {
125 gpr_cv_wait(&ct.done_cv, &ct.mu, gpr_inf_future(GPR_CLOCK_MONOTONIC));
126 }
127 gpr_mu_unlock(&ct.mu);
128 for (i = 0; i < nthreads; i++) {
129 thd[i].Join();
130 }
131 gpr_free(thd);
132 fprintf(stderr, "Saw cores [");
133 fflush(stderr);
134 for (i = 0; i < ct.ncores; i++) {
135 if (ct.used[i]) {
136 fprintf(stderr, "%d,", i);
137 fflush(stderr);
138 cores_seen++;
139 }
140 }
141 fprintf(stderr, "] (%d/%d)\n", cores_seen, ct.ncores);
142 fflush(stderr);
143 gpr_free(ct.used);
144 }
145
main(int argc,char * argv[])146 int main(int argc, char* argv[]) {
147 grpc_test_init(argc, argv);
148 cpu_test();
149 return 0;
150 }
151