src/testsuite/irqbench/irqbench.c

   1 /*
   2  * Copyright (C) 2006 Jan Kiszka <jan.kiszka@web.de>.
   3  *
   4  * Xenomai is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * Xenomai is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with Xenomai; if not, write to the Free Software Foundation,
  16  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  */
  18
  19 #include <limits.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <signal.h>
  24 #include <unistd.h>
  25 #include <sys/io.h>
  26 #include <sys/mman.h>
  27
  28
  29 #define SERPORT                 0
  30 #define PARPORT                 1
  31
  32 /* --- Serial port --- */
  33
  34 #define MCR_DTR                 0x01
  35 #define MCR_RTS                 0x02
  36 #define MCR_OUT2                0x08
  37
  38 #define MSR_DELTA               0x0F
  39
  40 #define LCR(base) (base + 3) /* Line Control Register */
  41 #define MCR(base) (base + 4) /* Modem Control Register */
  42 #define LSR(base) (base + 5) /* Line Status Register */
  43 #define MSR(base) (base + 6) /* Modem Status Register */
  44
  45 /* --- Parallel port --- */
  46
  47 #define CTRL_INIT               0x04
  48 #define CTRL_STROBE             0x10
  49
  50 #define DATA(base) (base + 0) /* Data register */
  51 #define STAT(base) (base + 1) /* Status register */
  52 #define CTRL(base) (base + 2) /* Control register */
  53
  54 static double tsc2ns_scale;
  55 static long long min_lat = LONG_MAX;
  56 static long long max_lat = LONG_MIN;
  57 static long long avg_lat;
  58 static long outer_loops;
  59 static int warmup = 1;
  60 static int terminate;
  61 static unsigned long port_ioaddr = 0x3F8;
  62 static int port_type = SERPORT;
  63 static unsigned int toggle;
  64 static long loop_avg;
  65 static long long period = 100000;
  66 static int trigger_trace;
  67
  68 static inline long long rdtsc(void)
  69 {
  70         unsigned long long tsc;
  71
  72         __asm__ __volatile__("rdtsc" : "=A" (tsc));
  73         return tsc;
  74 }
  75
  76 static long tsc2ns(long long tsc)
  77 {
  78         if (tsc > LONG_MAX || tsc < LONG_MIN) {
  79                 fprintf(stderr, "irqbench: overflow (%lld ns)!\n",
  80                         (long long)(tsc2ns_scale * (double)tsc));
  81                 exit(2);
  82         }
  83         return (long)(tsc2ns_scale * (double)tsc);
  84 }
  85
  86 static inline long long ns2tsc(long long ns)
  87 {
  88         return (long long)(((double)ns) / tsc2ns_scale);
  89 }
  90
  91 static void calibrate_tsc(void)
  92 {
  93         FILE *proc;
  94         char *lineptr = NULL;
  95         size_t len;
  96         double cpu_mhz;
  97
  98         proc = fopen("/proc/cpuinfo", "r");
  99         if (proc == NULL) {
 100                 perror("irqbench: Unable to open /proc/cpuinfo");
 101                 exit(1);
 102         }
 103
 104         while (getline(&lineptr, &len, proc) != -1)
 105                 if (strncmp(lineptr, "cpu MHz", 7) == 0) {
 106                         sscanf(strchr(lineptr, ':') + 1, "%lf", &cpu_mhz);
 107                         break;
 108                 }
 109
 110         if (lineptr)
 111                 free(lineptr);
 112         fclose(proc);
 113
 114         printf("CPU frequency: %.3lf MHz\n", cpu_mhz);
 115
 116         tsc2ns_scale = 1000.0 / cpu_mhz;
 117 }
 118
 119 static void sighand(int signal)
 120 {
 121         if (warmup)
 122                 exit(0);
 123         else
 124                 terminate = 1;
 125 }
 126
 127 static void do_inner_loop(void)
 128 {
 129         long long start, delay, timeout;
 130         long lat;
 131
 132         __asm__ __volatile__("cli");
 133
 134         if (port_type ==  SERPORT) {
 135                 start = rdtsc();
 136
 137                 toggle ^= MCR_RTS;
 138                 outb(toggle, MCR(port_ioaddr));
 139
 140                 timeout = start + period * 100;
 141                 while ((inb(MSR(port_ioaddr)) & MSR_DELTA) == 0 &&
 142                        rdtsc() < timeout);
 143
 144                 delay = rdtsc() - start;
 145         } else {
 146                 int status = inb(STAT(port_ioaddr));
 147
 148                 outb(0x08, DATA(port_ioaddr));
 149
 150                 start = rdtsc();
 151
 152                 outb(0x00, DATA(port_ioaddr));
 153
 154                 timeout = start + period * 100;
 155                 while (inb(STAT(port_ioaddr)) == status &&
 156                        rdtsc() < timeout);
 157
 158                 delay = rdtsc() - start;
 159         }
 160
 161         if (!warmup) {
 162                 lat = tsc2ns(delay);
 163
 164                 loop_avg += lat;
 165                 if (lat < min_lat)
 166                         min_lat = lat;
 167                 if (lat > max_lat) {
 168                         max_lat = lat;
 169                         if (trigger_trace) {
 170                                 if (port_type == SERPORT) {
 171                                         toggle ^= MCR_DTR;
 172                                         outb(toggle, MCR(port_ioaddr));
 173                                 } else {
 174                                         outb(0x18, DATA(port_ioaddr));
 175                                         outb(0x10, DATA(port_ioaddr));
 176                                 }
 177                         }
 178                 }
 179         }
 180
 181         __asm__ __volatile__("sti");
 182
 183         while (rdtsc() < start + period);
 184 }
 185
 186 int main(int argc, char *argv[])
 187 {
 188         int ioaddr_set = 0;
 189         unsigned long long count = 1;
 190         int c;
 191
 192         signal(SIGINT, sighand);
 193         signal(SIGTERM, sighand);
 194         signal(SIGHUP, sighand);
 195         signal(SIGALRM, sighand);
 196
 197         calibrate_tsc();
 198
 199         while ((c = getopt(argc, argv, "p:T:o:a:f")) != EOF)
 200                 switch (c) {
 201                 case 'p':
 202                         period = atoi(optarg) * 1000;
 203                         break;
 204
 205                 case 'T':
 206                         alarm(atoi(optarg));
 207                         break;
 208
 209                 case 'o':
 210                         port_type = atoi(optarg);
 211                         break;
 212
 213                 case 'a':
 214                         port_ioaddr = strtol(optarg, NULL, 0);
 215                         ioaddr_set = 1;
 216                         break;
 217
 218                 case 'f':
 219                         trigger_trace = 1;
 220                         break;
 221
 222                 default:
 223                         fprintf(stderr, "usage: irqbench [options]\n"
 224                                 "  [-p <period_us>]             # signal period, default=100 us\n"
 225                                 "  [-T <test_duration_seconds>] # default=0, so ^C to end\n"
 226                                 "  [-o <port_type>]             # 0=serial (default), 1=parallel\n"
 227                                 "  [-a <port_io_address>]       # default=0x3f8/0x378\n"
 228                                 "  [-f]                         # freeze trace for each new max latency\n");
 229                         exit(2);
 230                 }
 231
 232         /* set defaults for parallel port */
 233         if (port_type == 1 && !ioaddr_set)
 234                 port_ioaddr = 0x378;
 235
 236         if (iopl(3) < 0) {
 237                 fprintf(stderr, "irqbench: superuser permissions required\n");
 238                 exit(1);
 239         }
 240         mlockall(MCL_CURRENT | MCL_FUTURE);
 241
 242         switch (port_type) {
 243         case SERPORT:
 244                 toggle = MCR_OUT2;
 245                 inb(MSR(port_ioaddr));
 246                 break;
 247
 248         case PARPORT:
 249                 outb(CTRL_INIT, CTRL(port_ioaddr));
 250                 break;
 251
 252         default:
 253                 fprintf(stderr, "irqbench: invalid port type\n");
 254                 exit(1);
 255         }
 256
 257         period = ns2tsc(period);
 258
 259         printf("Port type:     %s\n"
 260                "Port address:  0x%lx\n\n",
 261                (port_type == SERPORT) ? "serial" : "parallel", port_ioaddr);
 262
 263         printf("Waiting on target...\n");
 264
 265         while (1)
 266                 if (port_type ==  SERPORT) {
 267                         toggle ^= MCR_RTS;
 268                         outb(toggle, MCR(port_ioaddr));
 269                         usleep(100000);
 270                         if ((inb(MSR(port_ioaddr)) & MSR_DELTA) != 0)
 271                                 break;
 272                 } else {
 273                         int status = inb(STAT(port_ioaddr));
 274
 275                         outb(0x08, DATA(port_ioaddr));
 276                         outb(0x00, DATA(port_ioaddr));
 277                         usleep(100000);
 278                         if (inb(STAT(port_ioaddr)) != status)
 279                                 break;
 280                 }
 281
 282         printf("Warming up...\n");
 283
 284         while (!terminate) {
 285                 long long loop_timeout = rdtsc() + ns2tsc(1000000000LL);
 286                 int inner_loops = 0;
 287
 288                 loop_avg = 0;
 289                 while (rdtsc() < loop_timeout) {
 290                         do_inner_loop();
 291                         inner_loops++;
 292                 }
 293
 294                 count += inner_loops;
 295
 296                 if (!warmup && !terminate) {
 297                         loop_avg /= inner_loops;
 298
 299                         printf("%llu: %.3f / %.3f / %.3f us\n", count,
 300                                ((double)min_lat) / 1000.0,
 301                                ((double)loop_avg) / 1000.0,
 302                                ((double)max_lat) / 1000.0);
 303
 304                         avg_lat += loop_avg;
 305                         outer_loops++;
 306                 } else
 307                         warmup = 0;
 308         }
 309
 310         avg_lat /= outer_loops;
 311         printf("---\n%llu: %.3f / %.3f / %.3f us\n", count,
 312                ((double)min_lat) / 1000.0, ((double)avg_lat) / 1000.0,
 313                ((double)max_lat) / 1000.0);
 314
 315         return 0;
 316 }