1 /* 2 * Copyright (c) 2015 Eugene Syromyatnikov <evgsyr (at) gmail.com> 3 * Copyright (c) 2015-2016 Dmitry V. Levin <ldv (at) 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 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