Please, review. The 'blklimits' command is the command-line interface
for I/O topology stuff in libblkid.
Karel
>From 4167095502b88cb62b6e856956c74ea188cec415 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@xxxxxxxxxx>
Date: Thu, 13 May 2010 10:14:43 +0200
Subject: [PATCH] blklimits: new command (print I/O topology)
The blklimits program is the command-line interface to working with
I/O topology support in the libblkid library. For example:
# blklimits /dev/sdb
alignment offset: 0
minimum io size: 4096
optimal io size: 32768
logical sector size: 512
physical sector size: 4096
CC: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Karel Zak <kzak@xxxxxxxxxx>
---
sys-utils/.gitignore | 1 +
sys-utils/Makefile.am | 8 ++
sys-utils/blklimits.8 | 69 ++++++++++++++++++
sys-utils/blklimits.c | 104 +++++++++++++++++++++++++++
tests/commands.sh.in | 1 +
tests/expected/blklimits/iolimits-512-4K-63 | 5 ++
tests/ts/blklimits/iolimits-512-4K-63 | 41 +++++++++++
7 files changed, 229 insertions(+), 0 deletions(-)
create mode 100644 sys-utils/blklimits.8
create mode 100644 sys-utils/blklimits.c
create mode 100644 tests/expected/blklimits/iolimits-512-4K-63
create mode 100755 tests/ts/blklimits/iolimits-512-4K-63
diff --git a/sys-utils/.gitignore b/sys-utils/.gitignore
index 7985d7a..7249430 100644
--- a/sys-utils/.gitignore
+++ b/sys-utils/.gitignore
@@ -1,4 +1,5 @@
arch
+blklimits
ctrlaltdel
cytune
dmesg
diff --git a/sys-utils/Makefile.am b/sys-utils/Makefile.am
index 76828cc..6e4c262 100644
--- a/sys-utils/Makefile.am
+++ b/sys-utils/Makefile.am
@@ -16,13 +16,21 @@ usrsbin_exec_PROGRAMS += ldattach tunelp rtcwake
dist_man_MANS += dmesg.1 ctrlaltdel.8 cytune.8 setarch.8 \
ldattach.8 lscpu.1 tunelp.8 rtcwake.8
+
+if BUILD_LIBBLKID
+usrsbin_exec_PROGRAMS += blklimits
+dist_man_MANS += blklimits.8
+blklimits_LDADD = $(ul_libblkid_la)
+blklimits_CFLAGS = $(AM_CFLAGS) -I$(ul_libblkid_incdir)
endif
+endif # linux
cytune_SOURCES = cytune.c cyclades.h
tunelp_SOURCES = tunelp.c lp.h
info_TEXINFOS = ipc.texi
+
if BUILD_FALLOCATE
usrbin_exec_PROGRAMS += fallocate
fallocate_SOURCES = fallocate.c ../lib/strtosize.c
diff --git a/sys-utils/blklimits.8 b/sys-utils/blklimits.8
new file mode 100644
index 0000000..a0fc4cf
--- /dev/null
+++ b/sys-utils/blklimits.8
@@ -0,0 +1,69 @@
+.\" -*- nroff -*-
+.TH BLKLIMITS 8 "May 2010" "Version 1.0"
+.SH NAME
+blklimits \- print block device I/O limits
+.SH SYNOPSIS
+.B blklimits
+.RB [ \-h ]
+.I devname
+.SH DESCRIPTION
+The
+.B blklimits
+program is the command-line interface to working with I/O topology support in
+the libblkid library.
+.PP
+The I/O limits information are exported to the userspace since kernel 2.6.31 by
+sys filesystem or ioclts. The libblkid library provides unified API for I/O
+limits. The library is also able to gather information from DM, MD, LVM and
+EVMS on systems with older kernels.
+.PP
+The exit code returned by
+.B blklimits
+is 0 on success and 1 on failure.
+.PP
+.SH OPTIONS
+.IP "\fB\-h, \-\-help\fP"
+Print help and exit.
+.SH I/O LIMITS INFORMATION
+.TP
+.I alignment offset
+Storage devices may report a physical block size that is bigger than the
+logical block size (for instance a drive with 4KiB physical sectors exposing
+512-byte logical blocks to the operating system). This parameter indicates how
+many bytes the beginning of the device is offset from the disk's natural
+alignment.
+.TP
+.I logical sector size
+This is the smallest unit the storage device can address. It is typically 512
+bytes.
+.TP
+.I minimum io size
+Storage devices may report a granularity or preferred minimum I/O size which is
+the smallest request the device can perform without incurring a performance
+penalty. For disk drives this is often the physical block size. For RAID
+arrays it is often the stripe chunk size. A properly aligned multiple of
+minimum_io_size is the preferred request size for workloads where a high number
+of I/O operations is desired.
+.TP
+.I optimal io size
+Storage devices may report an optimal I/O size, which is the device's preferred
+unit for sustained I/O. This is rarely reported for disk drives. For RAID
+arrays it is usually the stripe width or the internal track size. A properly
+aligned multiple of optimal_io_size is the preferred request size for workloads
+where sustained throughput is desired. If no optimal I/O size is reported this
+variable contains zero.
+.TP
+.I physical sector size
+This is the smallest unit a physical storage device can write atomically. It
+is usually the same as the logical block size but may be bigger. One example
+is SATA drives with 4KiB sectors that expose a 512-byte logical block size to
+the operating system. For stacked block devices the physical sector size
+variable contains the maximum physical sector size of the component devices.
+.SH AUTHORS
+.nf
+Karel Zak <kzak@xxxxxxxxxx>
+.fi
+.SH AVAILABILITY
+The blklimits command is part of the util-linux-ng package and is available from
+ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
+
diff --git a/sys-utils/blklimits.c b/sys-utils/blklimits.c
new file mode 100644
index 0000000..2c06738
--- /dev/null
+++ b/sys-utils/blklimits.c
@@ -0,0 +1,104 @@
+/*
+ * blklimits - utility to print block device I/O limits (aka I/O topology)
+ *
+ * Copyright (C) 2010 Red Hat, Inc. All rights reserved.
+ * Written by Karel Zak <kzak@xxxxxxxxxx>
+ *
+ * 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, 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.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <err.h>
+#include <errno.h>
+
+#include <blkid.h>
+
+#include "nls.h"
+
+static void __attribute__((__noreturn__)) usage(FILE *out)
+{
+ fprintf(out, _("Usage: %s [options] <device>\n\nOptions:\n"),
+ program_invocation_short_name);
+
+ fprintf(out, _(
+ " -h, --help this help\n"));
+
+ fprintf(out, _("\nFor more information see blklimits(1).\n"));
+
+ exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+int main(int argc, char **argv)
+{
+ blkid_probe pr = NULL;
+ blkid_topology tp;
+ char *devname;
+ int c, rc = EXIT_FAILURE;
+
+ struct option longopts[] = {
+ { "help", 0, 0, 'h' },
+ { NULL, 0, 0, 0 }
+ };
+
+ setlocale(LC_ALL, "");
+ bindtextdomain(PACKAGE, LOCALEDIR);
+ textdomain(PACKAGE);
+
+ while ((c = getopt_long(argc, argv, "h", longopts, NULL)) != -1) {
+ switch(c) {
+ case 'h':
+ usage(stdout);
+ break;
+ default:
+ usage(stderr);
+ break;
+ }
+ }
+
+ if (optind == argc)
+ errx(EXIT_FAILURE, _("no device specified."));
+
+ devname = argv[optind++];
+ pr = blkid_new_probe_from_filename(devname);
+ if (!pr) {
+ warn(_("%s: failed to create a new libblkid probe"), devname);
+ goto done;
+ }
+
+ tp = blkid_probe_get_topology(pr);
+ if (!tp) {
+ warnx(_("%s: failed to gather topology information"), devname);
+ goto done;
+ }
+
+ printf(_("alignment offset: %6lu\n"),
+ blkid_topology_get_alignment_offset(tp));
+ printf(_("minimum io size: %6lu\n"),
+ blkid_topology_get_minimum_io_size(tp));
+ printf(_("optimal io size: %6lu\n"),
+ blkid_topology_get_optimal_io_size(tp));
+ printf(_("logical sector size: %6lu\n"),
+ blkid_topology_get_logical_sector_size(tp));
+ printf(_("physical sector size: %6lu\n"),
+ blkid_topology_get_physical_sector_size(tp));
+
+ rc = EXIT_SUCCESS;
+done:
+ blkid_free_probe(pr);
+ return rc;
+}
+
diff --git a/tests/commands.sh.in b/tests/commands.sh.in
index f52a686..39e6028 100644
--- a/tests/commands.sh.in
+++ b/tests/commands.sh.in
@@ -48,5 +48,6 @@ TS_CMD_HWCLOCK=${TS_CMD_HWCLOCK-"$TOPDIR/hwclock/hwclock"}
TS_CMD_LSCPU=${TS_CMD_LSCPU-"$TOPDIR/sys-utils/lscpu"}
TS_CMD_BLKID=${TS_CMD_BLKID-"$TOPDIR/misc-utils/blkid"}
+TS_CMD_BLKLIMITS=${TS_CMD_BLKLIMITS-"$TOPDIR/sys-utils/blklimits"}
TS_CMD_FDISK=${TS_CMD_FDISK-"$TOPDIR/fdisk/fdisk"}
diff --git a/tests/expected/blklimits/iolimits-512-4K-63 b/tests/expected/blklimits/iolimits-512-4K-63
new file mode 100644
index 0000000..c07b1aa
--- /dev/null
+++ b/tests/expected/blklimits/iolimits-512-4K-63
@@ -0,0 +1,5 @@
+alignment offset: 3584
+minimum io size: 4096
+optimal io size: 32768
+logical sector size: 512
+physical sector size: 4096
diff --git a/tests/ts/blklimits/iolimits-512-4K-63 b/tests/ts/blklimits/iolimits-512-4K-63
new file mode 100755
index 0000000..2b1d0d8
--- /dev/null
+++ b/tests/ts/blklimits/iolimits-512-4K-63
@@ -0,0 +1,41 @@
+#!/bin/bash
+
+#
+# This file is part of util-linux-ng.
+#
+# This file 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 file 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.
+#
+
+TS_TOPDIR="$(dirname $0)/../.."
+TS_DESC="512/4K +alignment_offset"
+
+. $TS_TOPDIR/functions.sh
+ts_init "$*"
+ts_skip_nonroot
+
+modprobe --dry-run --quiet scsi_debug
+[ "$?" == 0 ] || ts_skip "missing scsi_debug module"
+
+rmmod scsi_debug &> /dev/null
+modprobe scsi_debug dev_size_mb=50 sector_size=512 physblk_exp=3 lowest_aligned=7
+[ "$?" == 0 ] || ts_die "Cannot init device"
+
+sleep 1
+
+DEVNAME=$(grep scsi_debug /sys/block/*/device/model | awk -F '/' '{print $4}')
+[ "x${DEVNAME}" == "x" ] && ts_die "Cannot found device"
+
+DEVICE="/dev/${DEVNAME}"
+
+$TS_CMD_BLKLIMITS $DEVICE >> $TS_OUTPUT 2>&1
+
+rmmod scsi_debug
+ts_finalize
--
1.6.6.1
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