tools/perf/bench/syscall.c

   1 /*
   2  *
   3  * syscall.c
   4  *
   5  * syscall: Benchmark for system call performance
   6  */
   7 #include "../perf.h"
   8 #include "../util/util.h"
   9 #include <subcmd/parse-options.h>
  10 #include "../builtin.h"
  11 #include "bench.h"
  12
  13 #include <stdio.h>
  14 #include <sys/time.h>
  15 #include <sys/syscall.h>
  16 #include <sys/types.h>
  17 #include <sys/wait.h>
  18 #include <unistd.h>
  19 #include <stdlib.h>
  20
  21 #ifndef __NR_fork
  22 #define __NR_fork -1
  23 #endif
  24
  25 #define LOOPS_DEFAULT 10000000
  26 static  int loops = LOOPS_DEFAULT;
  27
  28 static const struct option options[] = {
  29         OPT_INTEGER('l', "loop",        &loops,         "Specify number of loops"),
  30         OPT_END()
  31 };
  32
  33 static const char * const bench_syscall_usage[] = {
  34         "perf bench syscall <options>",
  35         NULL
  36 };
  37
  38 static void test_fork(void)
  39 {
  40         pid_t pid = fork();
  41
  42         if (pid < 0) {
  43                 fprintf(stderr, "fork failed\n");
  44                 exit(1);
  45         } else if (pid == 0) {
  46                 exit(0);
  47         } else {
  48                 if (waitpid(pid, NULL, 0) < 0) {
  49                         fprintf(stderr, "waitpid failed\n");
  50                         exit(1);
  51                 }
  52         }
  53 }
  54
  55 static void test_execve(void)
  56 {
  57         const char *pathname = "/bin/true";
  58         char *const argv[] = { (char *)pathname, NULL };
  59         pid_t pid = fork();
  60
  61         if (pid < 0) {
  62                 fprintf(stderr, "fork failed\n");
  63                 exit(1);
  64         } else if (pid == 0) {
  65                 execve(pathname, argv, NULL);
  66                 fprintf(stderr, "execve /bin/true failed\n");
  67                 exit(1);
  68         } else {
  69                 if (waitpid(pid, NULL, 0) < 0) {
  70                         fprintf(stderr, "waitpid failed\n");
  71                         exit(1);
  72                 }
  73         }
  74 }
  75
  76 static int bench_syscall_common(int argc, const char **argv, int syscall)
  77 {
  78         struct timeval start, stop, diff;
  79         unsigned long long result_usec = 0;
  80         const char *name = NULL;
  81         int i;
  82
  83         argc = parse_options(argc, argv, options, bench_syscall_usage, 0);
  84
  85         gettimeofday(&start, NULL);
  86
  87         for (i = 0; i < loops; i++) {
  88                 switch (syscall) {
  89                 case __NR_getppid:
  90                         getppid();
  91                         break;
  92                 case __NR_getpgid:
  93                         getpgid(0);
  94                         break;
  95                 case __NR_fork:
  96                         test_fork();
  97                         /* Only loop 10000 times to save time */
  98                         if (i == 10000)
  99                                 loops = 10000;
 100                         break;
 101                 case __NR_execve:
 102                         test_execve();
 103                         /* Only loop 10000 times to save time */
 104                         if (i == 10000)
 105                                 loops = 10000;
 106                         break;
 107                 default:
 108                         break;
 109                 }
 110         }
 111
 112         gettimeofday(&stop, NULL);
 113         timersub(&stop, &start, &diff);
 114
 115         switch (syscall) {
 116         case __NR_getppid:
 117                 name = "getppid()";
 118                 break;
 119         case __NR_getpgid:
 120                 name = "getpgid()";
 121                 break;
 122         case __NR_fork:
 123                 name = "fork()";
 124                 break;
 125         case __NR_execve:
 126                 name = "execve()";
 127                 break;
 128         default:
 129                 break;
 130         }
 131
 132         switch (bench_format) {
 133         case BENCH_FORMAT_DEFAULT:
 134                 printf("# Executed %'d %s calls\n", loops, name);
 135
 136                 result_usec = diff.tv_sec * 1000000;
 137                 result_usec += diff.tv_usec;
 138
 139                 printf(" %14s: %lu.%03lu [sec]\n\n", "Total time",
 140                        (unsigned long) diff.tv_sec,
 141                        (unsigned long) (diff.tv_usec/1000));
 142
 143                 printf(" %14lf usecs/op\n",
 144                        (double)result_usec / (double)loops);
 145                 printf(" %'14d ops/sec\n",
 146                        (int)((double)loops /
 147                              ((double)result_usec / (double)1000000)));
 148                 break;
 149
 150         case BENCH_FORMAT_SIMPLE:
 151                 printf("%lu.%03lu\n",
 152                        (unsigned long) diff.tv_sec,
 153                        (unsigned long) (diff.tv_usec / 1000));
 154                 break;
 155
 156         default:
 157                 /* reaching here is something disaster */
 158                 fprintf(stderr, "Unknown format:%d\n", bench_format);
 159                 exit(1);
 160                 break;
 161         }
 162
 163         return 0;
 164 }
 165
 166 int bench_syscall_basic(int argc, const char **argv)
 167 {
 168         return bench_syscall_common(argc, argv, __NR_getppid);
 169 }
 170
 171 int bench_syscall_getpgid(int argc, const char **argv)
 172 {
 173         return bench_syscall_common(argc, argv, __NR_getpgid);
 174 }
 175
 176 int bench_syscall_fork(int argc, const char **argv)
 177 {
 178         return bench_syscall_common(argc, argv, __NR_fork);
 179 }
 180
 181 int bench_syscall_execve(int argc, const char **argv)
 182 {
 183         return bench_syscall_common(argc, argv, __NR_execve);
 184 }