1 /*
2 * Copyright (c) 2018 Google, Inc.
3 *
4 * SPDX-License-Identifier: GPL-2.0-or-later
5 *
6 * A single small task executes. Task placement is verified.
7 */
8
9 #define _GNU_SOURCE
10 #include <errno.h>
11 #include <pthread.h>
12 #include <sched.h>
13 #include <time.h>
14
15 #include "tst_test.h"
16 #include "tst_safe_file_ops.h"
17 #include "tst_safe_pthread.h"
18
19 #include "trace_parse.h"
20 #include "util.h"
21
22 #define TRACE_EVENTS "sched_switch"
23
24 static int small_task_tid;
25
26 #define MIN_CORRECT_CLUSTER_PCT 90
27 #define BURN_SEC 5
task_fn(void * arg LTP_ATTRIBUTE_UNUSED)28 static void *task_fn(void *arg LTP_ATTRIBUTE_UNUSED)
29 {
30 small_task_tid = gettid();
31
32 printf("Small task executing for %ds...\n", BURN_SEC);
33 burn(BURN_SEC * USEC_PER_SEC, 1);
34
35 return NULL;
36 }
37
parse_results(void)38 static int parse_results(void)
39 {
40 int i, pct;
41 unsigned long long exec_start_us = 0;
42 unsigned long long correct_us = 0;
43 unsigned long long total_us = 0;
44 cpu_set_t cpuset;
45
46 if (find_cpus_with_capacity(0, &cpuset)) {
47 printf("Failed to find the CPUs in the little cluster.\n");
48 return -1;
49 }
50
51 for (i = 0; i < num_trace_records; i++) {
52 struct trace_sched_switch *t = trace[i].event_data;
53 unsigned long long segment_us;
54
55 if (trace[i].event_type != TRACE_RECORD_SCHED_SWITCH)
56 continue;
57
58 if (t->next_pid == small_task_tid) {
59 if (exec_start_us) {
60 printf("Trace parse fail: double exec start\n");
61 return -1;
62 }
63 exec_start_us = TS_TO_USEC(trace[i].ts);
64 continue;
65 }
66 if (t->prev_pid != small_task_tid)
67 continue;
68 /* End of task execution segment. */
69 if (!exec_start_us) {
70 printf("Trace parse fail: double exec end\n");
71 return -1;
72 }
73 segment_us = TS_TO_USEC(trace[i].ts);
74 segment_us -= exec_start_us;
75 exec_start_us = 0;
76 if (CPU_ISSET(trace[i].cpu, &cpuset))
77 correct_us += segment_us;
78 total_us += segment_us;
79 }
80
81 pct = (correct_us * 100) / total_us;
82 printf("Total time task scheduled: %lld usec\n"
83 "Time scheduled on a little CPU: %lld usec (%d%%)\n",
84 total_us, correct_us, pct);
85
86 return (pct < MIN_CORRECT_CLUSTER_PCT);
87 }
88
run(void)89 static void run(void)
90 {
91 pthread_t task_thread;
92
93 tst_res(TINFO, "Minimum correct cluster time percentage: %d%%\n",
94 MIN_CORRECT_CLUSTER_PCT);
95
96 /* configure and enable tracing */
97 tracefs_write("tracing_on", "0");
98 tracefs_write("buffer_size_kb", "16384");
99 tracefs_write("set_event", TRACE_EVENTS);
100 tracefs_write("trace", "\n");
101 tracefs_write("tracing_on", "1");
102
103 SAFE_PTHREAD_CREATE(&task_thread, NULL, task_fn, NULL);
104 SAFE_PTHREAD_JOIN(task_thread, NULL);
105
106 /* disable tracing */
107 tracefs_write("tracing_on", "0");
108 LOAD_TRACE();
109
110 if (parse_results())
111 tst_res(TFAIL, "Small task ran too much on non-small CPUs.\n");
112 else
113 tst_res(TPASS, "Small task ran appropriately on small CPUs.\n");
114 }
115
116 static struct tst_test test = {
117 .test_all = run,
118 .setup = trace_setup,
119 .cleanup = trace_cleanup,
120 };
121