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From: GeunSik Lim <leemgs1@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
	linux-rt-users <linux-rt-users@vger.kernel.org>,
	tglx <tglx@linutronix.de>, williams <williams@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [RESEND] [PATCH 1/2 V3] ftrace: fix typo about map of kernel priority in ftrace.txt file.
Date: Thu, 28 May 2009 10:36:11 +0900	[thread overview]
Message-ID: <1243474571.14685.37.camel@centos51> (raw)
In-Reply-To: <1242884360.31161.77.camel@centos51>



>From 5764d50e29e08d86f7f3b7dff66d7c1ad4762ff8 Mon Sep 17 00:00:00 2001
From: GeunSik,Lim <leemgs1@gmail.com>
Date: Thu, 28 May 2009 09:57:28 +0900
Subject: [PATCH 1/2] ftrace: fix typo about map of kernel priority in ftrace.txt file.

Fix typo about chart to map the kernel priority to user land priorities.

   * About sched_setscheduler(2)
      Processes scheduled under SCHED_FIFO or SCHED_RR
      can have a (user-space) static priority in the range 1 to 99.
      (reference: http://www.kernel.org/doc/man-pages/online/pages/
                  man2/sched_setscheduler.2.html)

   * From: Steven Rostedt
      0 to 98 - maps to RT tasks 99 to 1 (SCHED_RR or SCHED_FIFO)

      99 - maps to internal kernel threads that want to be lower than RT tasks
      but higher than SCHED_OTHER tasks. Although I'm not sure if any
      kernel thread actually uses this. I'm not even sure how this can be
      set, because the internal sched_setscheduler function does not allow
      for it.

      100 to 139 - maps nice levels -20 to 19. These are not set via
      sched_setscheduler, but are set via the nice system call.

      140 - reserved for idle tasks.

        Signed-off-by: GeunSik Lim <geunsik.lim@samsung.com>
        Acked-by     : Steven Rostedt <rostedt@goodmis.org>
        CC           : Ingo Molnar <mingo@elte.hu>
---
 Documentation/trace/ftrace.txt |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index fd9a3e6..e362f50 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -518,9 +518,18 @@ priority with zero (0) being the highest priority and the nice
 values starting at 100 (nice -20). Below is a quick chart to map
 the kernel priority to user land priorities.
 
-  Kernel priority: 0 to 99    ==> user RT priority 99 to 0
-  Kernel priority: 100 to 139 ==> user nice -20 to 19
-  Kernel priority: 140        ==> idle task priority
+   Kernel Space                     User Space
+ ===============================================================
+   0(high) to  98(low)     user RT priority 99(high) to 1(low)
+                           with SCHED_RR or SCHED_FIFO
+ ---------------------------------------------------------------
+  99                       sched_priority is not used in scheduling
+                           decisions(it must be specified as 0)
+ ---------------------------------------------------------------
+ 100(high) to 139(low)     user nice -20(high) to 19(low)
+ ---------------------------------------------------------------
+ 140                       idle task priority
+ ---------------------------------------------------------------
 
 The task states are:
 
-- 
1.6.3.1


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GeunSik Lim (  S A M S U N G     E L E C T R O N I C S  )
e-Mail  :1) geunsik.lim@samsung.com
         2) leemgs@gmail.com , leemgs1@gmail.com
HomePage: http://blog.naver.com/invain/
-----------------------------------------------


  parent reply	other threads:[~2009-05-28  1:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-21  5:39 [PATCH 0/1 ,v3] sched: fix typo in sched-rt-group.txt file GeunSik Lim
2009-05-28  1:36 ` [RESEND] [PATCH 0/2 V3] description about static priority GeunSik Lim
2009-05-28 13:06   ` Peter Zijlstra
2009-05-29  1:07     ` GeunSik Lim
2009-05-28  1:36 ` GeunSik Lim [this message]
2009-05-28  1:36 ` [RESEND] [PATCH 2/2 V3] sched: fix typo in sched-rt-group.txt file GeunSik Lim

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