1 #include <unistd.h>
2 #include <stdlib.h>
3 #include <pthread.h>
4 #include <spawn.h>
5 #include <mach/mach.h>
6 #include <mach/mach_time.h>
7 #include <TargetConditionals.h>
8 #include <sys/work_interval.h>
9 #include <sys/stat.h>
10 #include <sys/sysctl.h>
11
12 #include <darwintest.h>
13 #include <darwintest_utils.h>
14 #include <perfdata/perfdata.h>
15 #include "sched_test_utils.h"
16
17 #include "thread_group_fairness_workload_config.h"
18
19 T_GLOBAL_META(T_META_NAMESPACE("xnu.scheduler"),
20 T_META_RADAR_COMPONENT_NAME("xnu"),
21 T_META_RADAR_COMPONENT_VERSION("scheduler"),
22 T_META_TAG_PERF,
23 T_META_TAG_VM_NOT_ELIGIBLE);
24
25 static const size_t MAX_PDJ_PATH_LEN = 256;
26 static unsigned int num_cores;
27
28 static void
workload_config_load(void)29 workload_config_load(void)
30 {
31 int ret;
32 size_t len = 0;
33 ret = sysctlbyname("kern.workload_config", NULL, &len,
34 sched_thread_group_fairness_workload_config_plist,
35 sched_thread_group_fairness_workload_config_plist_len);
36 if (ret == -1 && errno == ENOENT) {
37 T_SKIP("kern.workload_config failed");
38 }
39 T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "kern.workload_config");
40 }
41
42 static void
workload_config_cleanup(void)43 workload_config_cleanup(void)
44 {
45 size_t len = 0;
46 sysctlbyname("kern.workload_config", NULL, &len, "", 1);
47 }
48
49 static void
environment_init(void)50 environment_init(void)
51 {
52 wait_for_quiescence_default();
53
54 num_cores = (unsigned int) dt_ncpu();
55
56 if (platform_is_amp()) {
57 /*
58 * Derecommend all clusters except the E cores, to ensure that thread groups
59 * compete over the same cores irrespective of CLPC's cluster recommendations
60 */
61 char *clpcctrl_args[] = {"-C", "e", NULL};
62 execute_clpcctrl(clpcctrl_args, false);
63 }
64
65 /*
66 * Load a test workload plist containing a Workload ID with
67 * WorkloadClass == DISCRETIONARY, in order to mark the thread group
68 * for that workload as THREAD_GROUP_FLAGS_EFFICIENT
69 */
70 T_ATEND(workload_config_cleanup);
71 workload_config_load();
72 }
73
74 static void
set_work_interval_id(work_interval_t * handle,uint32_t work_interval_flags)75 set_work_interval_id(work_interval_t *handle, uint32_t work_interval_flags)
76 {
77 int ret;
78 mach_port_t port = MACH_PORT_NULL;
79
80 ret = work_interval_copy_port(*handle, &port);
81 T_QUIET; T_ASSERT_POSIX_ZERO(ret, "work_interval_copy_port");
82
83 struct work_interval_workload_id_params wlid_params = {
84 .wlidp_flags = WORK_INTERVAL_WORKLOAD_ID_HAS_ID,
85 .wlidp_wicreate_flags = work_interval_flags,
86 .wlidp_name = (uintptr_t)"com.test.myapp.discretionary",
87 };
88
89 ret = __work_interval_ctl(WORK_INTERVAL_OPERATION_SET_WORKLOAD_ID, port, &wlid_params, sizeof(wlid_params));
90 T_QUIET; T_ASSERT_POSIX_ZERO(ret, "WORK_INTERVAL_OPERATION_SET_WORKLOAD_ID");
91 }
92
93 static uint32_t
make_work_interval(work_interval_t * handle,uint32_t work_type_flags)94 make_work_interval(work_interval_t *handle, uint32_t work_type_flags)
95 {
96 int ret;
97 uint32_t work_interval_flags = WORK_INTERVAL_FLAG_JOINABLE | WORK_INTERVAL_FLAG_GROUP | work_type_flags;
98 ret = work_interval_create(handle, work_interval_flags);
99 T_QUIET; T_ASSERT_POSIX_SUCCESS(ret, "work_interval_create");
100
101 if (work_type_flags & WORK_INTERVAL_FLAG_HAS_WORKLOAD_ID) {
102 set_work_interval_id(handle, work_interval_flags);
103 }
104 return work_interval_flags;
105 }
106
107 struct thread_data {
108 work_interval_t *handle;
109 uint32_t work_interval_flags;
110 };
111
112 static void *
spin_thread_fn(void * arg)113 spin_thread_fn(void *arg)
114 {
115 struct thread_data *info = (struct thread_data *)arg;
116 int ret;
117
118 /* Join the thread group associated with the work interval handle */
119 ret = work_interval_join(*(info->handle));
120 T_QUIET; T_ASSERT_POSIX_ZERO(ret, "work_interval_join");
121
122 /* Spin indefinitely */
123 volatile uint64_t spin_count = 0;
124 while (mach_absolute_time() < UINT64_MAX) {
125 spin_count++;
126 }
127 return NULL;
128 }
129
130 static void
start_threads(pthread_t * threads,struct thread_data * thread_datas,work_interval_t * handle,uint32_t work_interval_flags)131 start_threads(pthread_t *threads, struct thread_data *thread_datas, work_interval_t *handle, uint32_t work_interval_flags)
132 {
133 int ret;
134 for (unsigned int i = 0; i < num_cores; i++) {
135 thread_datas[i].handle = handle;
136 thread_datas[i].work_interval_flags = work_interval_flags;
137 ret = pthread_create(&threads[i], NULL, spin_thread_fn, &thread_datas[i]);
138 T_QUIET; T_ASSERT_POSIX_ZERO(ret, "pthread_create");
139 }
140 }
141
142 static uint64_t
snapshot_user_time_usec(pthread_t * threads)143 snapshot_user_time_usec(pthread_t *threads)
144 {
145 kern_return_t kr;
146 uint64_t cumulative_user_time_usec = 0;
147 mach_msg_type_number_t count = THREAD_BASIC_INFO_COUNT;
148 for (unsigned int i = 0; i < num_cores; i++) {
149 mach_port_t thread_port = pthread_mach_thread_np(threads[i]);
150 thread_basic_info_data_t info;
151 kr = thread_info(thread_port, THREAD_BASIC_INFO, (thread_info_t)&info, &count);
152 T_QUIET; T_ASSERT_MACH_SUCCESS(kr, "thread_info");
153 uint64_t thread_usr_usec = (uint64_t) (info.user_time.seconds) * USEC_PER_SEC + (uint64_t) info.user_time.microseconds;
154 cumulative_user_time_usec += thread_usr_usec;
155 }
156 return cumulative_user_time_usec;
157 }
158
159 T_DECL(thread_group_fairness,
160 "Ensure that thread groups tagged as higher priority do not starve out "
161 "thread groups tagged as lower priority when both behave as CPU spinners",
162 T_META_ASROOT(YES))
163 {
164 T_SETUPBEGIN;
165
166 environment_init();
167
168 /*
169 * Create two work intervals with corresponding thread groups that would
170 * be associated with differing priorities.
171 */
172 work_interval_t lower_pri_handle, higher_pri_handle;
173 uint32_t lower_pri_flags = make_work_interval(&lower_pri_handle, WORK_INTERVAL_TYPE_DEFAULT | WORK_INTERVAL_FLAG_HAS_WORKLOAD_ID);
174 uint32_t higher_pri_flags = make_work_interval(&higher_pri_handle, WORK_INTERVAL_TYPE_DEFAULT);
175
176 /* Start threads to join the lower priority thread group */
177 pthread_t lower_threads[num_cores];
178 struct thread_data lower_thread_datas[num_cores];
179 start_threads(lower_threads, lower_thread_datas, &lower_pri_handle, lower_pri_flags);
180
181 /* Start threads to join the higher priority thread group */
182 pthread_t higher_threads[num_cores];
183 struct thread_data higher_thread_datas[num_cores];
184 start_threads(higher_threads, higher_thread_datas, &higher_pri_handle, higher_pri_flags);
185
186 T_SETUPEND;
187
188 /* Snapshot thread runtimes */
189 uint64_t start_lower_priority_runtime_usec = snapshot_user_time_usec(lower_threads);
190 uint64_t start_higher_priority_runtime_usec = snapshot_user_time_usec(higher_threads);
191
192 /* Allow thread groups time to compete */
193 sleep(3);
194
195 /*
196 * Snapshot runtimes again and compare the usage ratio between the lower and
197 * higher priority thread groups, to determine whether the lower priority group
198 * has been starved
199 */
200 uint64_t finish_lower_priority_runtime_usec = snapshot_user_time_usec(lower_threads);
201 uint64_t finish_higher_priority_runtime_usec = snapshot_user_time_usec(higher_threads);
202
203 uint64_t lower_priority_runtime = finish_lower_priority_runtime_usec - start_lower_priority_runtime_usec;
204 uint64_t higher_priority_runtime = finish_higher_priority_runtime_usec - start_higher_priority_runtime_usec;
205
206 T_QUIET; T_ASSERT_GT(lower_priority_runtime, 10000LL, "lower priority thread group got at least 10ms of CPU time");
207 T_QUIET; T_ASSERT_GT(higher_priority_runtime, 10000LL, "higher priority thread group got at least 10ms of CPU time");
208
209 /* Record the observed runtime ratio */
210 char pdj_path[MAX_PDJ_PATH_LEN];
211 pdwriter_t writer = pdwriter_open_tmp("xnu", "scheduler.thread_group_fairness", 0, 0, pdj_path, MAX_PDJ_PATH_LEN);
212 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(writer, "pdwriter_open_tmp");
213
214 double runtime_ratio_value;
215 double total_runtime = (double)(lower_priority_runtime + higher_priority_runtime);
216 if (lower_priority_runtime <= higher_priority_runtime) {
217 runtime_ratio_value = (double)(lower_priority_runtime) / total_runtime;
218 } else {
219 runtime_ratio_value = (double)(higher_priority_runtime) / total_runtime;
220 }
221 T_LOG("Observed timeshare ratio: %f", runtime_ratio_value);
222
223 pdwriter_new_value(writer, "Thread Group Runtime Ratio", PDUNIT_CUSTOM(runtime_ratio), runtime_ratio_value);
224 pdwriter_record_larger_better(writer);
225 pdwriter_close(writer);
226 /* Ensure that the perfdata file can be copied by BATS */
227 T_QUIET; T_ASSERT_POSIX_ZERO(chmod(pdj_path, 0644), "chmod");
228
229 T_END;
230 }
231