From 8eec9db2436d52b74b18a34b2d479ba1acdf09b9 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Thu, 14 Aug 2008 11:19:07 +0200 Subject: [PATCH] ionice: cleanup man page Signed-off-by: Karel Zak --- schedutils/ionice.1 | 41 +++++++++++++++++------------------------ 1 file changed, 17 insertions(+), 24 deletions(-) diff --git a/schedutils/ionice.1 b/schedutils/ionice.1 index a17dd4f4..a434572d 100644 --- a/schedutils/ionice.1 +++ b/schedutils/ionice.1 @@ -2,29 +2,30 @@ .SH NAME ionice \- get/set program io scheduling class and priority .SH SYNOPSIS -.B ionice -[\fI-c\fR] \fI[-n\fR] [\fI-p\fR] [COMMAND [ARG...]] +.BI "ionice [\-p " pid "] [\-c " class "] [\-n " classdata " ] [\-t] [COMMAND [ARG ...]]" .SH DESCRIPTION -This program sets the io scheduling class and priority for a program. As of -this writing, Linux supports 3 scheduling classes: +This program sets or gets the io scheduling class and priority for a program. +If no arguments or just \fI-p\fR is given, \fIionice\fR will query the current +io scheduling class and priority for that process. -\fBIdle\fR. +As of this writing, Linux supports 3 scheduling classes: + +.IP "\fBIdle\fP" A program running with idle io priority will only get disk time when no other program has asked for disk io for a defined grace period. The impact of idle io processes on normal system activity should be zero. This scheduling class does not take a priority argument. Presently, this scheduling class is permitted for an ordinary user (since kernel 2.6.25). - -\fBBest effort\fR. +.IP "\fBBest effort\fP" This is the default scheduling class for any process that hasn't asked for a specific io priority. Programs inherit the CPU nice setting for io priorities. This class takes a priority argument from \fI0-7\fR, with lower number being higher priority. Programs running at the same best effort priority are served in a round-robin fashion. -\fBReal time\fR. +.IP "\fBReal time\fP" The RT scheduling class is given first access to the disk, regardless of what else is going on in the system. Thus the RT class needs to be used with some care, as it can starve other processes. As with the best effort class, @@ -32,26 +33,18 @@ some care, as it can starve other processes. As with the best effort class, will receive on each scheduling window. This scheduling class is not permitted for an ordinary (i.e., non-root) user. -If no arguments or just \fI-p\fR is given, \fIionice\fR will query the -current io scheduling class and priority for that process. - .SH OPTIONS -.LP -.TP 7 -\fB-c\fP -The scheduling class. 1 for real time, 2 for best-effort, 3 for idle. -.TP 7 -\fB-n\fP +.IP "\fB-c \fIclass\fP" +The scheduling class. \fI1\fR for real time, \fI2\fR for best-effort, \fI3\fR for idle. +.IP "\fB-n \fIclassdata\fP" The scheduling class data. This defines the class data, if the class accepts an argument. For real time and best-effort, \fI0-7\fR is valid data. -.TP 7 -\fB-p\fP +.IP "\fB-p \fIpid\fP" Pass in a process pid to change an already running process. If this argument is not given, \fBionice\fP will run the listed program with the given parameters. -.TP 7 -\fB-t\fP +.IP "\fB-t\fP" Ignore failure to set requested priority. If COMMAND is specified, run it even in case it was not possible to set desired scheduling priority, what can happen due to insufficient privilegies or old kernel version. @@ -59,15 +52,15 @@ can happen due to insufficient privilegies or old kernel version. .SH EXAMPLES .LP .TP 7 -# \fBionice\fP -c3 -p89 +# \fBionice\fP -c 3 -p 89 .TP 7 Sets process with PID 89 as an idle io process. .TP 7 -# \fBionice\fP -c2 -n0 bash +# \fBionice\fP -c 2 -n 0 bash .TP 7 Runs 'bash' as a best-effort program with highest priority. .TP 7 -# \fBionice\fP -p89 +# \fBionice\fP -p 89 .TP 7 Returns the class and priority of the process with PID 89. -- 2.39.5