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diff --git a/schedutils/chrt.1 b/schedutils/chrt.1 new file mode 100644 index 0000000..166579e --- /dev/null +++ b/schedutils/chrt.1 @@ -0,0 +1,173 @@ +.\" 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, +.\" version 2, as published by the Free Software Foundation. +.\" +.\" The GNU General Public License's references to "object code" +.\" and "executables" are to be interpreted as the output of any +.\" document formatting or typesetting system, including +.\" intermediate and printed output. +.\" +.\" This manual 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. +.\" +.TH CHRT 1 "January 2016" "util-linux" "User Commands" +.SH NAME +chrt \- manipulate the real-time attributes of a process +.SH SYNOPSIS +.B chrt +[options] +.IR priority\ command\ [ argument ...] +.br +.B chrt +[options] +.B \-p +.RI [ priority ]\ pid +.SH DESCRIPTION +.PP +.B chrt +sets or retrieves the real-time scheduling attributes of an existing \fIpid\fR, +or runs \fIcommand\fR with the given attributes. + +.SH POLICIES +.TP +\fB\-o\fR, \fB\-\-other\fR +Set scheduling policy to +.BR SCHED_OTHER . +This is the default Linux scheduling policy. +.TP +\fB\-f\fR, \fB\-\-fifo\fR +Set scheduling policy to \fBSCHED_FIFO\fR. +.TP +\fB\-r\fR, \fB\-\-rr\fR +Set scheduling policy to +.BR SCHED_RR . +When no policy is defined, the +.B SCHED_RR +is used as the default. +.TP +\fB\-b\fR, \fB\-\-batch\fR +Set scheduling policy to +.B SCHED_BATCH +(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 scheduling policy to +.B SCHED_DEADLINE +(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 the kernel is +runtime <= deadline <= period. +.B chrt +copies \fIperiod\fR to \fIdeadline\fR if \fB\-\-sched\-deadline\fR is not specified and +\fIdeadline\fR to \fIruntime\fR if \fB\-\-sched\-runtime\fR is not specified. +It means that at least \fB\-\-sched\-period\fR has to be specified. See +.BR sched (7) +for more details. + +.SH "SCHEDULING OPTIONS" +.TP +\fB\-T\fR, \fB\-\-sched\-runtime\fR \fInanoseconds\fR +Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific). +.TP +\fB\-P\fR, \fB\-\-sched\-period\fR \fInanoseconds\fR +Specifies period parameter for SCHED_DEADLINE policy (Linux-specific). +.TP +\fB\-D\fR, \fB\-\-sched\-deadline\fR \fInanoseconds\fR +Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific). +.TP +\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, supported since 2.6.31). + +.SH OPTIONS +.TP +.BR -a ,\ --all-tasks +Set or retrieve the scheduling attributes of all the tasks (threads) for a +given PID. +.TP +.BR -m ,\ --max +Show minimum and maximum valid priorities, then exit. +.TP +.BR -p ,\ --pid +Operate on an existing PID and do not launch a new task. +.TP +.BR -v ,\ --verbose +Show status information. +.TP +.BR -V ,\ --version +Display version information and exit. +.TP +.BR -h ,\ --help +Display help text and exit. +.SH USAGE +.TP +The default behavior is to run a new command: +.B chrt +.I priority +.IR command\ [ arguments ] +.TP +You can also retrieve the real-time attributes of an existing task: +.B chrt \-p +.I pid +.TP +Or set them: +.B chrt \-r \-p +.I priority pid +.SH PERMISSIONS +A user must possess +.B CAP_SYS_NICE +to change the scheduling attributes of a process. Any user can retrieve the +scheduling information. + +.SH NOTES +Only +.BR SCHED_FIFO , +.B SCHED_OTHER +and +.B SCHED_RR +are part of POSIX 1003.1b Process Scheduling. The other scheduling attributes +may be ignored on some systems. +.P +Linux' default scheduling policy is +.BR SCHED_OTHER . +.SH SEE ALSO +.BR nice (1), +.BR renice (1), +.BR taskset (1), +.BR sched (7) +.sp +See +.BR sched_setscheduler (2) +for a description of the Linux scheduling scheme. +.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 +https://www.kernel.org/pub/linux/utils/util-linux/. |