.\" chrt(1) manpage
.\"
.\" Copyright (C) 2004 Robert Love
+.\" Copyright (C) 2015 Karel Zak <kzak@redhat.com>
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License,
.\" with this program; if not, write to the Free Software Foundation, Inc.,
.\" 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
.\"
-.TH CHRT 1 "August 2014" "util-linux" "User Commands"
+.TH CHRT 1 "January 2016" "util-linux" "User Commands"
.SH NAME
chrt \- manipulate the real-time attributes of a process
.SH SYNOPSIS
.PP
.B chrt
sets or retrieves the real-time scheduling attributes of an existing \fIpid\fR,
-or runs \fIcommand\fR with the given attributes. Both the policy (one of
-.BR SCHED_OTHER ,
-.BR SCHED_FIFO ,
-.BR SCHED_RR ,
-.BR SCHED_BATCH ,
-.BR SCHED_DEADLINE ,
-or
-.BR SCHED_IDLE )
-and the priority can be set and retrieved.
-.PP
-The
-.BR SCHED_BATCH
-policy is supported since Linux 2.6.16. The
-.BR SCHED_IDLE
-policy is supported since Linux 2.6.23. The
-.BR SCHED_DEADLINE
-policy is supported since Linux 3.14.
-.PP
-The
-.BR SCHED_RESET_ON_FORK
-flag for policies SCHED_RR and SCHED_FIFO is supported
-since Linux 2.6.31.
-.SH OPTIONS
+or runs \fIcommand\fR with the given attributes.
+
+.SH POLICIES
.TP
-.BR -a ,\ --all-tasks
-Set or retrieve the scheduling attributes of all the tasks (threads) for a
-given PID.
+\fB\-o\fR, \fB\-\-other\fR
+Set policy scheduling policy to
+.BR SCHED_OTHER .
+This is the default Linux scheduling policy.
+.TP
+\fB\-f\fR, \fB\-\-fifo\fR
+Set policy scheduling policy to SCHED_FIFO.
+.TP
+\fB\-r\fR, \fB\-\-rr\fR
+Set scheduling policy to
+.BR SCHED_RR .
+When policy is not defined the
+.B SCHED_RR
+is used as default.
.TP
-.BR -b ,\ --batch
+\fB\-b\fR, \fB\-\-batch\fR
Set scheduling policy to
.B SCHED_BATCH
-(Linux-specific). The priority argument has to be set to zero.
+(Linux-specific, supported since 2.6.16). The priority argument has to be set to zero.
+.TP
+\fB\-i\fR, \fB\-\-idle\fR
+Set scheduling policy to
+.B SCHED_IDLE
+(Linux-specific, supported since 2.6.23). The priority argument has to be set to zero.
.TP
.BR -d ,\ --deadline
Set policy scheduling policy to
.BR SCHED_DEADLINE
-(Linux-specific). The priority argument has to be set to zero. See also \fB\-\-sched\-runtime\fR,
-\fB\-\-sched\-deadline\fR and \fB\-\-sched\-period\fR. The relation between
-the options required by kernel is runtime <= deadline <= period.
+(Linux-specific, supported since 3.14). The priority argument has to be set to
+zero. See also \fB\-\-sched\-runtime\fR, \fB\-\-sched\-deadline\fR and
+\fB\-\-sched\-period\fR. The relation between the options required by kernel is
+runtime <= deadline <= period.
.B chrt
copies \fIperiod\fR to \fIdeadline\fR if \fB\-\-sched\-deadline\fR is no specified and
\fIdeadline\fR to \fIruntime\fR if \fB\-\-sched\-runtime\fR is no specified. It means at least
\fB\-\-sched\-period\fR has to be specified. See
.BR sched (7)
for more details.
+
+.SH "SCHEDULING OPTIONS"
.TP
-.BR -f ,\ --fifo
-Set scheduling policy to
-.BR SCHED_FIFO .
-.TP
-.BR -i ,\ --idle
-Set scheduling policy to
-.B SCHED_IDLE
-(Linux-specific). The priority argument has to be set to zero.
-.TP
-.BR -m ,\ --max
-Show minimum and maximum valid priorities, then exit.
+\fB\-T\fR, \fB\-\-sched\-runtime\fR \fInanoseconds\fR
+Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific).
.TP
-.BR -o ,\ --other
-Set policy scheduling policy to
-.BR SCHED_OTHER .
+\fB\-P\fR, \fB\-\-sched\-period\fR \fInanoseconds\fR
+Specifies period parameter for SCHED_DEADLINE policy (Linux-specific).
.TP
-.BR -p ,\ --pid
-Operate on an existing PID and do not launch a new task.
+\fB\-D\fR, \fB\-\-sched\-deadline\fR \fInanoseconds\fR
+Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific).
.TP
-.BR -R ,\ --reset-on-fork
+\fB\-R\fR, \fB\-\-reset-on-fork\fR
Add
.B SCHED_RESET_ON_FORK
flag to the
.B SCHED_FIFO
or
.B SCHED_RR
-scheduling policy (Linux-specific).
-.TP
-.BR -r ,\ --rr
-Set scheduling policy to
-.BR SCHED_RR .
-When policy is not defined the
-.B SCHED_RR
-is used as default.
+scheduling policy (Linux-specific, supported since 2.6.31).
+
+.SH OPTIONS
.TP
-\fB\-T\fR, \fB\-\-sched\-runtime\fR \fInanoseconds\fR
-Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific).
+.BR -a ,\ --all-tasks
+Set or retrieve the scheduling attributes of all the tasks (threads) for a
+given PID.
.TP
-\fB\-P\fR, \fB\-\-sched\-period\fR \fInanoseconds\fR
-Specifies period parameter for SCHED_DEADLINE policy (Linux-specific).
+.BR -m ,\ --max
+Show minimum and maximum valid priorities, then exit.
.TP
-\fB\-D\fR, \fB\-\-sched\-deadline\fR \fInanoseconds\fR
-Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific).
+.BR -p ,\ --pid
+Operate on an existing PID and do not launch a new task.
.TP
.BR -v ,\ --verbose
Show status information.
.BR CAP_SYS_NICE
to change the scheduling attributes of a process. Any user can retrieve the
scheduling information.
+
.SH NOTES
Only
.BR SCHED_FIFO ,
.SH SEE ALSO
.BR taskset (1),
.BR nice (1),
-.BR renice (1)
+.BR renice (1),
.BR sched (7)
.sp
See
.BR sched_setscheduler (2)
for a description of the Linux scheduling scheme.
-.SH AUTHOR
-Written by Robert M. Love.
-.SH COPYRIGHT
-Copyright \(co 2004 Robert M. Love.
-This is free software; see the source for copying conditions. There is NO
-warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+.SH AUTHORS
+.UR rml@tech9.net
+Robert Love
+.UE
+.br
+.UR kzak@redhat.com
+Karel Zak
+.UE
.SH AVAILABILITY
The chrt command is part of the util-linux package and is available from
ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
-.TH FALLOCATE 1 "September 2011" "util-linux" "User Commands"
-.SH NAME
-fallocate \- preallocate or deallocate space to a file
-.SH SYNOPSIS
-.B fallocate
-.RB [ \-c ]
-.RB [ \-n ]
-.RB [ \-p ]
-.RB [ \-z ]
-.RB [ \-o
-.IR offset ]
-.B \-l
-.IR length
-.I filename
-.PP
-.B fallocate \-d
-.RB [ \-o
-.IR offset ]
-.RB [ \-l
-.IR length ]
-.I filename
-.SH DESCRIPTION
-.B fallocate
-is used to manipulate the allocated disk space for a file, either to deallocate
-or preallocate it. For filesystems which support the fallocate system call,
-preallocation is done quickly by allocating blocks and marking them as
-uninitialized, requiring no IO to the data blocks. This is much faster than
-creating a file by filling it with zeros.
-.PP
-The exit code returned by
-.B fallocate
-is 0 on success and 1 on failure.
-.SH OPTIONS
-The \fIlength\fR and \fIoffset\fR
-arguments may be followed by the multiplicative suffixes KiB (=1024),
-MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is
-optional, e.g., "K" has the same meaning as "KiB") or the suffixes
-KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
-.PP
-The options \fB\-\-collapse\-range\fP, \fB\-\-dig\-holes\fP, \fB\-\-punch\-hole\fP and
-\fB\-\-zero\-range\fP are mutually exclusive.
-.TP
-.BR \-c , " \-\-collapse\-range"
-Removes a byte range from a file, without leaving a hole. The byte range
-to be collapsed starts at \fIoffset\fP and continues
-for \fIlength\fR bytes. At the completion of the operation, the contents of
-the file starting at the location \fIoffset\fR+\fIlength\fR will be appended at the
-location \fIoffset\fR, and the file will be \fIlength\fR bytes smaller. The option
-\fB\-\-keep\-size\fR may not be specified for colapse range operation.
-.sp
-Available since Linux 3.15 for ext4 (only for extent-based files) and XFS.
-.TP
-.BR \-d , " \-\-dig\-holes"
-Detect and dig holes. This makes the file sparse in-place, without using extra
-disk space. The minimum size of the hole depends on filesystem I/O block size
-(usually 4096 bytes). Also, when using this option, \fB\-\-keep\-size\fP is
-implied. If no range is specified by \fB\-\-offset\fP and \fB\-\-length\fP,
-then the entire file is analyzed for holes.
-.sp
-You can think of this option as doing a "\fBcp --sparse\fP" and then renaming
-the destination file to the original, without the need for extra disk space.
-.sp
-See \fB\-\-punch\-hole\fP for a list of supported filesystems.
-.TP
-.BR \-l , " \-\-length " \fIlength
-Specifies the length of the range, in bytes.
-.TP
-.BR \-n , " \-\-keep\-size"
-Do not modify the apparent length of the file. This may effectively allocate
-blocks past EOF, which can be removed with a truncate.
-.TP
-.BR \-o , " \-\-offset " \fIoffset
-Specifies the beginning offset of the range, in bytes.
-.TP
-.BR \-p , " \-\-punch\-hole"
-Deallocates space (i.e., creates a hole) in the byte range starting at
-\fIoffset\fP and continuing for \fIlength\fR bytes. Within the
-specified range, partial filesystem blocks are zeroed, and whole
-filesystem blocks are removed from the file. After a successful
-call, subsequent reads from this range will return zeroes. This option
-may not be specified at the same time as the \fB\-\-zero\-range\fP option.
-Also, when using this option, \fB\-\-keep\-size\fP is implied.
-.sp
-Supported for XFS (since Linux 2.6.38), ext4 (since Linux 3.0),
-Btrfs (since Linux 3.7) and tmpfs (since Linux 3.5).
-.TP
-.BR \-v , " \-\-verbose"
-Enable verbose mode.
-.TP
-.BR \-z , " \-\-zero\-range"
-Zeroes space in the byte range starting at \fIoffset\fP and
-continuing for \fIlength\fR bytes. Within the specified range, blocks are
-preallocated for the regions that span the holes in the file. After
-a successful call, subsequent reads from this range will return zeroes.
-.sp
-Zeroing is done within the filesystem preferably by converting the
-range into unwritten extents. This approach means that the specified
-range will not be physically zeroed out on the device (except for
-partial blocks at the either end of the range), and I/O is
-(otherwise) required only to update metadata.
-.sp
-Option \fB\-\-keep\-size\fP can be specified to prevent file length
-modification.
-.sp
-Available since Linux 3.14 for ext4 (only for extent-based files) and XFS.
-.TP
-.BR \-V , " \-\-version"
-Display version information and exit.
-.TP
-.BR \-h , " \-\-help"
-Display help text and exit.
.SH AUTHORS
.UR sandeen@redhat.com
Eric Sandeen
.UR kzak@redhat.com
Karel Zak
.UE
-.SH SEE ALSO
-.BR fallocate (2),
-.BR posix_fallocate (3),
-.BR truncate (1)
-.SH AVAILABILITY
-The fallocate command is part of the util-linux package and is available from
-.UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
-Linux Kernel Archive
-.UE .
projects / thirdparty / util-linux.git / commitdiff
