disk-utils/elvtune.c

   1 /*
   2  *  elvtune.c - I/O elevator tuner
   3  *
   4  *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  *  This file may be redistributed under the terms of the GNU General
  20  *  Public License, version 2.
  21  */
  22
  23 #include <fcntl.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <getopt.h>
  27 #include <unistd.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <sys/ioctl.h>
  31 #include <sys/utsname.h>
  32 #include "nls.h"
  33 #include "blkdev.h"
  34 #include "linux_version.h"
  35
  36 /* this has to match with the kernel structure */
  37 /* current version for ac19 and 2.2.16 */
  38 typedef struct blkelv_ioctl_arg_s {
  39         int queue_ID;
  40         int read_latency;
  41         int write_latency;
  42         int max_bomb_segments;
  43 } blkelv_ioctl_arg_t;
  44
  45 static void
  46 usage(void) {
  47         fprintf(stderr, "elvtune (%s)\n", PACKAGE_STRING);
  48         fprintf(stderr, _("usage:\n"));
  49         fprintf(stderr, "\telvtune [-r r_lat] [-w w_lat] [-b b_lat]"
  50                         " /dev/blkdev1 [/dev/blkdev2...]\n");
  51         fprintf(stderr, "\telvtune -h\n");
  52         fprintf(stderr, "\telvtune -v\n");
  53         fprintf(stderr, _("\tNOTE: elvtune only works with 2.4 kernels\n"));
  54         /* (ioctls exist in 2.2.16 - 2.5.57) */
  55 }
  56
  57 static void
  58 version(void) {
  59         fprintf(stderr, "elvtune (%s)\n", PACKAGE_STRING);
  60 }
  61
  62 int
  63 main(int argc, char * argv[]) {
  64         int read_value = 0xbeefbeef, write_value = 0xbeefbeef, bomb_value = 0xbeefbeef;
  65         int read_set, write_set, bomb_set, set;
  66         char * devname;
  67         int fd;
  68         blkelv_ioctl_arg_t elevator;
  69
  70         read_set = write_set = bomb_set = set = 0;
  71
  72         setlocale(LC_MESSAGES, "");
  73         bindtextdomain(PACKAGE, LOCALEDIR);
  74         textdomain(PACKAGE);
  75
  76         for (;;) {
  77                 int opt;
  78
  79                 opt = getopt(argc, argv, "r:w:b:hv");
  80                 if (opt == -1)
  81                         break;
  82                 switch (opt) {
  83                 case 'r':
  84                         read_value = atoi(optarg);
  85                         read_set = set = 1;
  86                         break;
  87                 case 'w':
  88                         write_value = atoi(optarg);
  89                         write_set = set = 1;
  90                         break;
  91                 case 'b':
  92                         bomb_value = atoi(optarg);
  93                         bomb_set = set = 1;
  94                         break;
  95
  96                 case 'h':
  97                         usage(), exit(0);
  98                 case 'v':
  99                         version(), exit(0);
 100
 101                 case '?':
 102                 default:
 103                 case ':':
 104                         fprintf(stderr, _("parse error\n"));
 105                         exit(1);
 106                 }
 107         }
 108
 109         if (optind >= argc)
 110                 fprintf(stderr, _("missing blockdevice, use -h for help\n")), exit(1);
 111
 112         while (optind < argc) {
 113                 devname = argv[optind++];
 114
 115                 fd = open(devname, O_RDONLY|O_NONBLOCK);
 116                 if (fd < 0) {
 117                         perror("open");
 118                         break;
 119                 }
 120
 121                 /* mmj: If we get EINVAL it's not a 2.4 kernel, so warn about
 122                    that and exit. It should return ENOTTY however, so check for
 123                    that as well in case it gets corrected in the future */
 124
 125                 if (ioctl(fd, BLKELVGET, &elevator) < 0) {
 126                         int errsv = errno;
 127                         perror("ioctl get");
 128                         if ((errsv == EINVAL || errsv == ENOTTY) &&
 129                             get_linux_version() >= KERNEL_VERSION(2,5,58)) {
 130                                 fprintf(stderr,
 131                                         _("\nelvtune is only useful on older "
 132                                         "kernels;\nfor 2.6 use IO scheduler "
 133                                         "sysfs tunables instead..\n"));
 134                         }
 135                         break;
 136                 }
 137
 138                 if (set) {
 139                         if (read_set)
 140                                 elevator.read_latency = read_value;
 141                         if (write_set)
 142                                 elevator.write_latency = write_value;
 143                         if (bomb_set)
 144                                 elevator.max_bomb_segments = bomb_value;
 145
 146                         if (ioctl(fd, BLKELVSET, &elevator) < 0) {
 147                                 perror("ioctl set");
 148                                 break;
 149                         }
 150                         if (ioctl(fd, BLKELVGET, &elevator) < 0) {
 151                                 perror("ioctl reget");
 152                                 break;
 153                         }
 154                 }
 155
 156                 printf("\n%s elevator ID\t\t%d\n", devname, elevator.queue_ID);
 157                 printf("\tread_latency:\t\t%d\n", elevator.read_latency);
 158                 printf("\twrite_latency:\t\t%d\n", elevator.write_latency);
 159                 printf("\tmax_bomb_segments:\t%d\n\n", elevator.max_bomb_segments);
 160
 161                 if (close(fd) < 0) {
 162                         perror("close");
 163                         break;
 164                 }
 165         }
 166
 167         return 0;
 168 }