1 /*
2 * Test to validate that we can schedule threads on all hw.ncpus cores according to _os_cpu_number
3 *
4 * <rdar://problem/29545645>
5 * <rdar://problem/30445216>
6 *
7 * xcrun -sdk macosx.internal clang -o cpucount cpucount.c -ldarwintest -g -Weverything
8 * xcrun -sdk iphoneos.internal clang -arch arm64 -o cpucount-ios cpucount.c -ldarwintest -g -Weverything
9 * xcrun -sdk macosx.internal clang -o cpucount cpucount.c -ldarwintest -arch arm64e -Weverything
10 */
11
12 #include <darwintest.h>
13
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <unistd.h>
17 #include <pthread.h>
18 #include <sys/sysctl.h>
19 #include <sys/proc_info.h>
20 #include <libproc.h>
21
22 #include <mach/mach.h>
23 #include <mach/mach_time.h>
24
25 #include <os/tsd.h> /* private header for _os_cpu_number */
26
27 T_GLOBAL_META(
28 T_META_RUN_CONCURRENTLY(false),
29 T_META_BOOTARGS_SET("enable_skstb=1"),
30 T_META_CHECK_LEAKS(false),
31 T_META_ASROOT(true),
32 T_META_ALL_VALID_ARCHS(true),
33 T_META_RADAR_COMPONENT_NAME("xnu"),
34 T_META_RADAR_COMPONENT_VERSION("scheduler")
35 );
36
37 #define KERNEL_BOOTARGS_MAX_SIZE 1024
38 static char kernel_bootargs[KERNEL_BOOTARGS_MAX_SIZE];
39
40 #define KERNEL_VERSION_MAX_SIZE 1024
41 static char kernel_version[KERNEL_VERSION_MAX_SIZE];
42
43 static mach_timebase_info_data_t timebase_info;
44
45 static uint64_t
abs_to_nanos(uint64_t abs)46 abs_to_nanos(uint64_t abs)
47 {
48 return abs * timebase_info.numer / timebase_info.denom;
49 }
50
51 static int32_t
get_csw_count()52 get_csw_count()
53 {
54 struct proc_taskinfo taskinfo;
55 int rv;
56
57 rv = proc_pidinfo(getpid(), PROC_PIDTASKINFO, 0, &taskinfo, sizeof(taskinfo));
58 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "PROC_PIDTASKINFO");
59
60 return taskinfo.pti_csw;
61 }
62
63 // noinline hopefully keeps the optimizer from hoisting it out of the loop
64 // until rdar://68253516 is fixed.
65 __attribute__((noinline))
66 static uint32_t
fixed_os_cpu_number(void)67 fixed_os_cpu_number(void)
68 {
69 uint32_t cpu_number = _os_cpu_number();
70
71 return cpu_number;
72 }
73
74
75 T_DECL(count_cpus, "Tests we can schedule bound threads on all hw.ncpus cores and that _os_cpu_number matches")
76 {
77 int rv;
78
79 setvbuf(stdout, NULL, _IONBF, 0);
80 setvbuf(stderr, NULL, _IONBF, 0);
81
82 /* Validate what kind of kernel we're on */
83 size_t kernel_version_size = sizeof(kernel_version);
84 rv = sysctlbyname("kern.version", kernel_version, &kernel_version_size, NULL, 0);
85 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "kern.version");
86
87 T_LOG("kern.version: %s\n", kernel_version);
88
89 /* Double check that darwintest set the boot arg we requested */
90 size_t kernel_bootargs_size = sizeof(kernel_bootargs);
91 rv = sysctlbyname("kern.bootargs", kernel_bootargs, &kernel_bootargs_size, NULL, 0);
92 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "kern.bootargs");
93
94 T_LOG("kern.bootargs: %s\n", kernel_bootargs);
95
96 if (NULL == strstr(kernel_bootargs, "enable_skstb=1")) {
97 T_FAIL("enable_skstb=1 boot-arg is missing");
98 }
99
100 kern_return_t kr;
101 kr = mach_timebase_info(&timebase_info);
102 T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "mach_timebase_info");
103
104 int bound_cpu_out = 0;
105 size_t bound_cpu_out_size = sizeof(bound_cpu_out);
106 rv = sysctlbyname("kern.sched_thread_bind_cpu", &bound_cpu_out, &bound_cpu_out_size, NULL, 0);
107
108 if (rv == -1) {
109 if (errno == ENOENT) {
110 T_FAIL("kern.sched_thread_bind_cpu doesn't exist, must set enable_skstb=1 boot-arg on development kernel");
111 }
112 if (errno == EPERM) {
113 T_FAIL("must run as root");
114 }
115 }
116
117 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "read kern.sched_thread_bind_cpu");
118 T_QUIET; T_ASSERT_EQ(bound_cpu_out, -1, "kern.sched_thread_bind_cpu should exist, start unbound");
119
120 struct sched_param param = {.sched_priority = 63};
121
122 rv = pthread_setschedparam(pthread_self(), SCHED_FIFO, ¶m);
123 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "pthread_setschedparam");
124
125 uint32_t sysctl_ncpu = 0;
126 size_t ncpu_size = sizeof(sysctl_ncpu);
127 rv = sysctlbyname("hw.ncpu", &sysctl_ncpu, &ncpu_size, NULL, 0);
128 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "sysctlbyname(hw.ncpu)");
129
130 T_LOG("hw.ncpu: %2d\n", sysctl_ncpu);
131
132 T_ASSERT_GT(sysctl_ncpu, 0, "at least one CPU exists");
133
134 for (uint32_t cpu_to_bind = 0; cpu_to_bind < sysctl_ncpu; cpu_to_bind++) {
135 int32_t before_csw_count = get_csw_count();
136 T_LOG("(csw %4d) attempting to bind to cpu %2d\n", before_csw_count, cpu_to_bind);
137
138 uint64_t start = mach_absolute_time();
139
140 rv = sysctlbyname("kern.sched_thread_bind_cpu", NULL, 0, &cpu_to_bind, sizeof(cpu_to_bind));
141
142 uint64_t end = mach_absolute_time();
143
144 if (rv == -1 && errno == ENOTSUP) {
145 T_SKIP("Binding is available, but this process doesn't support binding (e.g. Rosetta on Aruba)");
146 }
147
148 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "kern.sched_thread_bind_cpu(%u)", cpu_to_bind);
149
150 uint32_t os_cpu_number_reported = fixed_os_cpu_number();
151
152 bound_cpu_out = 0;
153 rv = sysctlbyname("kern.sched_thread_bind_cpu", &bound_cpu_out, &bound_cpu_out_size, NULL, 0);
154 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "read kern.sched_thread_bind_cpu");
155
156 T_QUIET; T_EXPECT_EQ((int)cpu_to_bind, bound_cpu_out,
157 "should report bound cpu id matching requested bind target");
158
159 uint64_t delta_abs = end - start;
160 uint64_t delta_ns = abs_to_nanos(delta_abs);
161
162 int32_t after_csw_count = get_csw_count();
163
164 T_LOG("(csw %4d) bound to cpu %2d in %f milliseconds\n",
165 after_csw_count, cpu_to_bind,
166 ((double)delta_ns / 1000000.0));
167
168 if (cpu_to_bind > 0) {
169 T_QUIET; T_EXPECT_LT(before_csw_count, after_csw_count,
170 "should have had to context switch to execute the bind");
171 }
172
173 T_LOG("cpu %2d reported id %2d\n",
174 cpu_to_bind, os_cpu_number_reported);
175
176 T_QUIET;
177 T_EXPECT_EQ(cpu_to_bind, os_cpu_number_reported,
178 "should report same CPU number as was bound to");
179 }
180
181 int unbind = -1; /* pass -1 in order to unbind the thread */
182
183 rv = sysctlbyname("kern.sched_thread_bind_cpu", NULL, 0, &unbind, sizeof(unbind));
184
185 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "kern.sched_thread_bind_cpu(%u)", unbind);
186
187 rv = sysctlbyname("kern.sched_thread_bind_cpu", &bound_cpu_out, &bound_cpu_out_size, NULL, 0);
188
189 T_QUIET; T_ASSERT_POSIX_SUCCESS(rv, "read kern.sched_thread_bind_cpu");
190 T_QUIET; T_ASSERT_EQ(bound_cpu_out, -1, "thread should be unbound at the end");
191
192 T_PASS("test has run threads on all CPUS");
193 }
194