1 /*
2 * Copyright (c) 2015 Eugene Syromyatnikov <evgsyr@gmail.com>
3 * Copyright (c) 2015-2016 Dmitry V. Levin <ldv@altlinux.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /**
30 * @file
31 * This test burns some CPU cycles in user space and kernel space in order to
32 * get some non-zero values returned by times(2).
33 */
34
35 #include "tests.h"
36 #include <sched.h>
37 #include <stdio.h>
38 #include <time.h>
39 #include <unistd.h>
40
41 #include <asm/unistd.h>
42 #include <sys/times.h>
43 #include <sys/wait.h>
44
45 enum {
46 NUM_USER_ITERS = 1000000,
47 PARENT_CPUTIME_LIMIT_NSEC = 200000000,
48 CHILD_CPUTIME_LIMIT_NSEC = 300000000
49 };
50
51 int
main(void)52 main (void)
53 {
54 struct timespec ts;
55 volatile int dummy = 0;
56 int i = 0;
57
58 pid_t pid = fork();
59 if (pid < 0)
60 perror_msg_and_fail("fork");
61
62 const long cputime_limit =
63 pid ? PARENT_CPUTIME_LIMIT_NSEC : CHILD_CPUTIME_LIMIT_NSEC;
64
65 /* Enjoying my user time */
66 while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
67 if (ts.tv_sec || ts.tv_nsec >= cputime_limit)
68 break;
69
70 if (i && !(ts.tv_sec || ts.tv_nsec))
71 error_msg_and_skip("clock_gettime(CLOCK_PROCESS_CPUTIME_ID, {0, 0})");
72
73 for (i = 0; i < NUM_USER_ITERS; ++i)
74 ++dummy;
75 }
76
77 /* Enjoying my system time */
78 while (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) == 0) {
79 if (ts.tv_sec || ts.tv_nsec >= cputime_limit * 2)
80 break;
81
82 sched_yield();
83 }
84
85 if (pid == 0) {
86 return 0;
87 } else {
88 wait(NULL);
89 }
90
91 struct tms tbuf;
92 unsigned long long llres;
93
94 /*
95 * On systems where user's and kernel's long types are the same,
96 * prefer direct times syscall over libc's times function because
97 * the latter is more prone to return value truncation.
98 */
99 #undef USE_LIBC_SYSCALL
100 #if defined __NR_times && \
101 !defined(LINUX_MIPSN32) && \
102 !(defined __x86_64__ && defined __ILP32__)
103 # define USE_LIBC_SYSCALL 1
104 #endif
105
106 #if defined USE_LIBC_SYSCALL
107 long res = syscall(__NR_times, &tbuf);
108
109 if (-1L == res)
110 perror_msg_and_skip("times");
111 else
112 llres = (unsigned long) res;
113 #elif defined __NR_times && defined __x86_64__ && defined __ILP32__
114 register long arg asm("rdi") = (long) &tbuf;
115 asm volatile("syscall\n\t"
116 : "=a"(llres)
117 : "0"(__NR_times), "r"(arg)
118 : "memory", "cc", "r11", "cx");
119 if (llres > 0xfffffffffffff000)
120 return 77;
121 #else
122 clock_t res = times(&tbuf);
123
124 if ((clock_t) -1 == res)
125 perror_msg_and_skip("times");
126 if (sizeof(res) < sizeof(unsigned long long))
127 llres = (unsigned long) res;
128 else
129 llres = res;
130 #endif
131
132 printf("times({tms_utime=%llu, tms_stime=%llu, ",
133 (unsigned long long) tbuf.tms_utime,
134 (unsigned long long) tbuf.tms_stime);
135 printf("tms_cutime=%llu, tms_cstime=%llu}) = %llu\n",
136 (unsigned long long) tbuf.tms_cutime,
137 (unsigned long long) tbuf.tms_cstime,
138 llres);
139 puts("+++ exited with 0 +++");
140
141 return 0;
142 }
143