RLIMIT_RTTIME documentation for getrlimit.2

RLIMIT_RTTIME documentation for getrlimit.2

[Michael Kerrisk]

Peter,

Below is the draft text that I will add to the getrlimit.2 man page to describe
RLIMIT_RTTIME.  Does it look okay to you?  (I will add a pointer in
sched_setscheduler.2 to this description in getrlimit.2.)

       RLIMIT_RTTIME (Since Linux 2.6.25)
              Specifies a limit on the amount of CPU time that a
              process  scheduled  under  a  real-time scheduling
              policy may consume without making a blocking  sys-
              tem  call.   For  the  purpose of this limit, each
              time a process makes a blocking system  call,  the
              count  of  its consumed CPU time is reset to zero.
              The CPU time count is not  reset  if  the  process
              continues  trying to use the CPU but is preempted,
              its   time   slice   expires,    or    it    calls
              sched_yield(2).

              Upon  reaching the soft limit, the process is sent
              a SIGXCPU  signal.   If  the  process  catches  or
              ignores  this  signal  and continues consuming CPU
              time, then SIGXCPU will  be  generated  once  each
              second  until  the hard limit is reached, at which
              point the process is sent a SIGKILL signal.

              The intended use of this limit is to stop  a  run-
              away real-time process from locking up the system.

Cheers,

Michael

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Re: RLIMIT_RTTIME documentation for getrlimit.2

[Michael Kerrisk]

Hey Peter,

Ping!

Cheers,

Michael


---------- Forwarded message ----------
From: Michael Kerrisk <mtk.manpages-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
Date: Fri, Apr 18, 2008 at 6:52 PM
Subject: RLIMIT_RTTIME documentation for getrlimit.2
To: Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>
Cc: Eugene Teo <eugeneteo-X4ZF2iejbADYtjvyW6yDsg@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Neil Horman <nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org>, Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>,
linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org


Peter,

Below is the draft text that I will add to the getrlimit.2 man page to describe
RLIMIT_RTTIME.  Does it look okay to you?  (I will add a pointer in
sched_setscheduler.2 to this description in getrlimit.2.)

      RLIMIT_RTTIME (Since Linux 2.6.25)
             Specifies a limit on the amount of CPU time that a
             process  scheduled  under  a  real-time scheduling
             policy may consume without making a blocking  sys-
             tem  call.   For  the  purpose of this limit, each
             time a process makes a blocking system  call,  the
             count  of  its consumed CPU time is reset to zero.
             The CPU time count is not  reset  if  the  process
             continues  trying to use the CPU but is preempted,
             its   time   slice   expires,    or    it    calls
             sched_yield(2).

             Upon  reaching the soft limit, the process is sent
             a SIGXCPU  signal.   If  the  process  catches  or
             ignores  this  signal  and continues consuming CPU
             time, then SIGXCPU will  be  generated  once  each
             second  until  the hard limit is reached, at which
             point the process is sent a SIGKILL signal.

             The intended use of this limit is to stop  a  run-
             away real-time process from locking up the system.

Cheers,

Michael




-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html
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Re: RLIMIT_RTTIME documentation for getrlimit.2

[Peter Zijlstra]

On Mon, 2008-04-28 at 13:44 +0200, Michael Kerrisk wrote:
> Hey Peter,
> 
> Ping!

Thanks for the reminder ;-)

> Cheers,
> 
> Michael
> 
> 
> ---------- Forwarded message ----------
> From: Michael Kerrisk <mtk.manpages-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
> Date: Fri, Apr 18, 2008 at 6:52 PM
> Subject: RLIMIT_RTTIME documentation for getrlimit.2
> To: Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>
> Cc: Eugene Teo <eugeneteo-X4ZF2iejbADYtjvyW6yDsg@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
> Neil Horman <nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org>, Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>,
> linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> 
> 
> Peter,
> 
> Below is the draft text that I will add to the getrlimit.2 man page to describe
> RLIMIT_RTTIME.  Does it look okay to you?  (I will add a pointer in
> sched_setscheduler.2 to this description in getrlimit.2.)
> 
>       RLIMIT_RTTIME (Since Linux 2.6.25)
>              Specifies a limit on the amount of CPU time that a
>              process  scheduled  under  a  real-time scheduling
>              policy may consume without making a blocking  sys-
>              tem  call.   For  the  purpose of this limit, each
>              time a process makes a blocking system  call,  the
>              count  of  its consumed CPU time is reset to zero.
>              The CPU time count is not  reset  if  the  process
>              continues  trying to use the CPU but is preempted,
>              its   time   slice   expires,    or    it    calls
>              sched_yield(2).
> 
>              Upon  reaching the soft limit, the process is sent
>              a SIGXCPU  signal.   If  the  process  catches  or
>              ignores  this  signal  and continues consuming CPU
>              time, then SIGXCPU will  be  generated  once  each
>              second  until  the hard limit is reached, at which
>              point the process is sent a SIGKILL signal.
> 
>              The intended use of this limit is to stop  a  run-
>              away real-time process from locking up the system.

Looks excellent, thanks!

Acked-by: Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>

in so far that is applicable to man pages ;-)

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Re: RLIMIT_RTTIME documentation for getrlimit.2

[Michael Kerrisk]

>  > Below is the draft text that I will add to the getrlimit.2 man page to describe
>  > RLIMIT_RTTIME.  Does it look okay to you?  (I will add a pointer in
>  > sched_setscheduler.2 to this description in getrlimit.2.)
>  >
>  >       RLIMIT_RTTIME (Since Linux 2.6.25)
>  >              Specifies a limit on the amount of CPU time that a
>  >              process  scheduled  under  a  real-time scheduling
>  >              policy may consume without making a blocking  sys-
>  >              tem  call.   For  the  purpose of this limit, each
>  >              time a process makes a blocking system  call,  the
>  >              count  of  its consumed CPU time is reset to zero.
>  >              The CPU time count is not  reset  if  the  process
>  >              continues  trying to use the CPU but is preempted,
>  >              its   time   slice   expires,    or    it    calls
>  >              sched_yield(2).
>  >
>  >              Upon  reaching the soft limit, the process is sent
>  >              a SIGXCPU  signal.   If  the  process  catches  or
>  >              ignores  this  signal  and continues consuming CPU
>  >              time, then SIGXCPU will  be  generated  once  each
>  >              second  until  the hard limit is reached, at which
>  >              point the process is sent a SIGKILL signal.
>  >
>  >              The intended use of this limit is to stop  a  run-
>  >              away real-time process from locking up the system.
>
>
> Looks excellent, thanks!

Good -- thanks for checking it over.

>  Acked-by: Peter Zijlstra <a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>
>
>  in so far that is applicable to man pages ;-)

It works for me.

Cheers,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html
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