1 /******************************************************************************/ 2 /* */ 3 /* Copyright (c) International Business Machines Corp., 2008 */ 4 /* */ 5 /* This program is free software; you can redistribute it and/or modify */ 6 /* it under the terms of the GNU General Public License as published by */ 7 /* the Free Software Foundation; either version 2 of the License, or */ 8 /* (at your option) any later version. */ 9 /* */ 10 /* This program is distributed in the hope that it will be useful, */ 11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ 12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See */ 13 /* the GNU General Public License for more details. */ 14 /* */ 15 /* You should have received a copy of the GNU General Public License */ 16 /* along with this program; if not, write to the Free Software */ 17 /* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ 18 /* */ 19 /******************************************************************************/ 20 21 /******************************************************************************/ 22 /* */ 23 /* File: cpuctl_latency_check_task.c */ 24 /* */ 25 /* Description: This is a c program that runs a task which does frequent sleep*/ 26 /* on a busy machine and checks if there is any added latency */ 27 /* The file is to be used by script */ 28 /* */ 29 /* Total Tests: 1 */ 30 /* */ 31 /* Test Name: cpu_controller_latency_tests */ 32 /* */ 33 /* Test Assertion */ 34 /* Please refer to the file cpuctl_testplan.txt */ 35 /* */ 36 /* Author: Sudhir Kumar skumar (at) linux.vnet.ibm.com */ 37 /* */ 38 /* History: */ 39 /* Created- 26/11/2008 -Sudhir Kumar <skumar (at) linux.vnet.ibm.com> */ 40 /* */ 41 /******************************************************************************/ 42 43 #include <unistd.h> 44 #include <math.h> 45 #include <signal.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <sys/time.h> 49 #include <string.h> 50 51 #include "../libcontrollers/libcontrollers.h" 52 53 /* #define VERBOSE 1 to print verbose output */ 54 55 #ifdef VERBOSE 56 #define verbose(x...) printf(x) 57 #else 58 #define verbose(x...) do {} while (0); 59 #endif 60 61 #define NUM_TIMES 200 /* How many intervals you want to check */ 62 #define INTERVALS 1 /* How many milliseconds interval in iterations */ 63 #define USECONDS 1000 /* microseconds to sleep */ 64 #define info printf("The results FAIL is just intuitive and not exact" \ 65 " failure. Please look at cpuctl_testplan.txt in the test directory.\n"); 66 67 char *TCID = "cpuctl_latency_tests"; 68 int TST_COUNT = 1; 69 int TST_TOTAL = 1; 70 pid_t script_pid; 71 72 int main(int argc, char *argv[]) 73 { 74 int count, i = 0, iteration = 0; 75 int fail = 0, ALLOWED; 76 char mytaskfile[FILENAME_MAX]; 77 int test_num; 78 struct timeval prev_time, cur_time; 79 unsigned int actual, actual_s, actual_us, sleeptime; 80 unsigned int delta, delta_max = 0; 81 pid_t script_pid; 82 83 if ((argc < 4) || (argc > 5)) { 84 printf("Invalid #args received from script. Exiting test..\n"); 85 exit(1); 86 } 87 88 test_num = atoi(argv[1]); 89 script_pid = (pid_t) atoi(argv[2]); 90 ALLOWED = atoi(argv[3]); 91 if ((test_num < 0) || (script_pid < 0) || (ALLOWED < 0)) { 92 printf("Invalid args received from script. Exiting test..\n"); 93 exit(1); 94 } 95 96 if (test_num == 2) { 97 strncpy(mytaskfile, argv[4], FILENAME_MAX); 98 strncat(mytaskfile, "/tasks", 99 FILENAME_MAX - strlen(mytaskfile) - 1); 100 write_to_file(mytaskfile, "a", getpid()); 101 102 /* Give a chance to other tasks too to go to their class */ 103 sleep(8); 104 } 105 106 printf("TINFO \tThe latency check task started\n"); 107 108 /* Let us start capturing the time now */ 109 for (count = NUM_TIMES; count >= 0; count -= INTERVALS) { 110 if (gettimeofday(&prev_time, NULL) == -1) 111 perror("In Iteration no 1 \n"); 112 /* sleep for specified time */ 113 sleeptime = count * USECONDS; 114 usleep(sleeptime); 115 116 if (gettimeofday(&cur_time, NULL) == -1) 117 perror("In Iteration no 1 \n"); 118 119 /* Get the actual difference */ 120 actual_s = cur_time.tv_sec - prev_time.tv_sec; 121 actual_us = cur_time.tv_usec - prev_time.tv_usec; 122 actual = 1e6 * actual_s + actual_us; 123 delta = actual - sleeptime; 124 125 /* capture the maximum latency observed */ 126 if (delta >= delta_max) { 127 delta_max = delta; 128 iteration = i; 129 } 130 131 if (delta > ALLOWED) 132 fail = 1; 133 134 verbose("Iteration %d: Exp(us) =%u, Actual =%u delta = %u\n", 135 i++, sleeptime, actual, delta); 136 } 137 138 if (fail) { 139 printf("FAIL \tThe Latency test %d failed\n", test_num); 140 printf("Max latency observed = %u in Iteration %d\n", 141 delta_max, iteration); 142 info; 143 } else { 144 printf("PASS \tThe Latency test %d passed\n", test_num); 145 printf("Max latency observed = %u microsec in Iteration %d\n", 146 delta_max, iteration); 147 } 148 return fail; 149 } 150
