From mboxrd@z Thu Jan  1 00:00:00 1970
From: John Sigler <linux.kernel@free.fr>
Subject: Re: Pin-pointing the root of unusual application latencies
Date: Wed, 25 Jul 2007 17:46:28 +0200
Message-ID: <46A77054.8040203@free.fr>
References: <469600F7.3060603@free.fr> <20070725133835.GA17616@elte.hu> <46A758B5.9070602@free.fr> <200707251728.00207.fzu@wemgehoertderstaat.de>
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Cc: Ingo Molnar <mingo@elte.hu>, linux-rt-users@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Karsten Wiese <fzu@wemgehoertderstaat.de>
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Karsten Wiese wrote:

> John Sigler wrote:
> 
>> Is there some form of priority inheritance? Does the IRQ handler get a 
>> priority boost if a high priority task is waiting for it?
> 
> No. But that would be "nice to have".

No to the first question? to the second question? or to both? :-)

In kernel/futex.c does "PI" stand for Priority Inheritance?

e.g.

/*
  * Priority Inheritance state:
  */
struct futex_pi_state {
	/*
	 * list of 'owned' pi_state instances - these have to be
	 * cleaned up in do_exit() if the task exits prematurely:
	 */
	struct list_head list;

	/*
	 * The PI object:
	 */
	struct rt_mutex pi_mutex;

	struct task_struct *owner;
	atomic_t refcount;

	union futex_key key;
};