+++ /dev/null
-.\" -*- nroff -*-
-.TH ELVTUNE 8 "March 2000" "util-linux" "System Administration"
-.SH NAME
-elvtune \- I/O elevator tuner
-.SH SYNOPSIS
-.B elvtune
-.RB [ \-r
-.IR r_lat ]
-.RB [ \-w
-.IR w_lat ]
-.RB [ \-b
-.IR b_max ]
-.IR device ...
-.br
-.B elvtune \-h
-.br
-.B elvtune \-v
-.SH DESCRIPTION
-.B elvtune
-allows to tune the I/O elevator per blockdevice queue. The
-tuning can be safely done at runtime. Tuning the elevator means
-being able to change disk performance and interactiveness.
-In the output of
-.B elvtune
-the address of the queue tuned will be shown;
-it can be considered as a queue ID.
-Multiple partitions on the same harddisk will
-share the same queue and so tuning one partition will be
-like tuning the whole HD.
-.SH OPTIONS
-.TP
-.BI -r \ r_lat
-Set the maximum latency that the I/O scheduler will provide on
-each read.
-.TP
-.BI -w \ w_lat
-Set the maximum latency that the I/O scheduler will provide on
-each write.
-.TP
-.BI -b \ b_max
-Set the maximum coalescing factor allowed on writes when there are reads
-pending in the queue.
-.TP
-.BI -h
-Display help text and exit.
-.TP
-.BI -v
-Display version information and exit.
-.SH NOTE
-Actually, the only fields tunable are those relative
-to the IO scheduler. It's not possible to select
-a one-way or two-way elevator yet.
-.PP
-For logical blockdevices like LVM the tuning has to
-be done on the
-.I physical
-devices. Tuning the queue of the LVM logical device
-is useless.
-.SH RETURN VALUE
-0 on success and 1 on failure.
-.SH HISTORY
-Ioctls for tuning elevator behaviour were added in Linux 2.3.99-pre1.
-.SH AUTHORS
-Andrea Arcangeli <andrea@suse.de> SuSE
-.SH AVAILABILITY
-The elvtune command is part of the util-linux package and is available from
-ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
+++ /dev/null
-/*
- * elvtune.c - I/O elevator tuner
- *
- * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- */
-
-/*
- * This command is deprecated. The utility is in maintenance mode,
- * meaning we keep them in source tree for backward compatibility
- * only. Do not waste time making this command better, unless the
- * fix is about security or other very critical issue.
- *
- * See Documentation/deprecated.txt for more information.
- */
-
-#include <fcntl.h>
-#include <errno.h>
-#include <stdio.h>
-#include <getopt.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/ioctl.h>
-#include <sys/utsname.h>
-#include "nls.h"
-#include "blkdev.h"
-#include "closestream.h"
-#include "linux_version.h"
-
-/* this has to match with the kernel structure */
-/* current version for ac19 and 2.2.16 */
-typedef struct blkelv_ioctl_arg_s {
- int queue_ID;
- int read_latency;
- int write_latency;
- int max_bomb_segments;
-} blkelv_ioctl_arg_t;
-
-static void
-usage(void) {
- fprintf(stderr, "elvtune (%s)\n", PACKAGE_STRING);
- fprintf(stderr, _("usage:\n"));
- fprintf(stderr, "\telvtune [-r r_lat] [-w w_lat] [-b b_lat]"
- " /dev/blkdev1 [/dev/blkdev2...]\n");
- fprintf(stderr, "\telvtune -h\n");
- fprintf(stderr, "\telvtune -v\n");
- fprintf(stderr, _("\tNOTE: elvtune only works with 2.4 kernels\n"));
- /* (ioctls exist in 2.2.16 - 2.5.57) */
-}
-
-static void
-version(void) {
- fprintf(stderr, UTIL_LINUX_VERSION);
-}
-
-int
-main(int argc, char * argv[]) {
- int read_value = 0xbeefbeef, write_value = 0xbeefbeef, bomb_value = 0xbeefbeef;
- int read_set, write_set, bomb_set, set;
- char * devname;
- int fd;
- blkelv_ioctl_arg_t elevator;
-
- read_set = write_set = bomb_set = set = 0;
-
- setlocale(LC_MESSAGES, "");
- bindtextdomain(PACKAGE, LOCALEDIR);
- textdomain(PACKAGE);
- atexit(close_stdout);
-
- for (;;) {
- int opt;
-
- opt = getopt(argc, argv, "r:w:b:hv");
- if (opt == -1)
- break;
- switch (opt) {
- case 'r':
- read_value = atoi(optarg);
- read_set = set = 1;
- break;
- case 'w':
- write_value = atoi(optarg);
- write_set = set = 1;
- break;
- case 'b':
- bomb_value = atoi(optarg);
- bomb_set = set = 1;
- break;
-
- case 'h':
- usage(), exit(0);
- case 'v':
- version(), exit(0);
-
- default:
- usage(), exit(1);
- }
- }
-
- if (optind >= argc)
- fprintf(stderr, _("missing blockdevice, use -h for help\n")), exit(1);
-
- while (optind < argc) {
- devname = argv[optind++];
-
- fd = open(devname, O_RDONLY|O_NONBLOCK);
- if (fd < 0) {
- perror("open");
- break;
- }
-
- /* mmj: If we get EINVAL it's not a 2.4 kernel, so warn about
- that and exit. It should return ENOTTY however, so check for
- that as well in case it gets corrected in the future */
-
- if (ioctl(fd, BLKELVGET, &elevator) < 0) {
- int errsv = errno;
- perror("ioctl get");
- if ((errsv == EINVAL || errsv == ENOTTY) &&
- get_linux_version() >= KERNEL_VERSION(2,5,58)) {
- fprintf(stderr,
- _("\nelvtune is only useful on older "
- "kernels;\nfor 2.6 use IO scheduler "
- "sysfs tunables instead..\n"));
- }
- break;
- }
-
- if (set) {
- if (read_set)
- elevator.read_latency = read_value;
- if (write_set)
- elevator.write_latency = write_value;
- if (bomb_set)
- elevator.max_bomb_segments = bomb_value;
-
- if (ioctl(fd, BLKELVSET, &elevator) < 0) {
- perror("ioctl set");
- break;
- }
- if (ioctl(fd, BLKELVGET, &elevator) < 0) {
- perror("ioctl reget");
- break;
- }
- }
-
- printf("\n%s elevator ID\t\t%d\n", devname, elevator.queue_ID);
- printf("\tread_latency:\t\t%d\n", elevator.read_latency);
- printf("\twrite_latency:\t\t%d\n", elevator.write_latency);
- printf("\tmax_bomb_segments:\t%d\n\n", elevator.max_bomb_segments);
-
- if (close(fd) < 0) {
- perror("close");
- break;
- }
- }
-
- return 0;
-}
projects / thirdparty / util-linux.git / commitdiff
