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From: "Martijn Sipkema" <msipkema@sipkema-digital.com>
To: "The Linux Audio Developers' Mailing List" 
	<linux-audio-dev@music.columbia.edu>,
	"Paul Davis" <paul@linuxaudiosystems.com>
Cc: <florin@sgi.com>, <linux-kernel@vger.kernel.org>,
	<linux-audio-dev@music.columbia.edu>,
	<albert@users.sourceforge.net>
Subject: Re: [linux-audio-dev] Re: desktop and multimedia as an afterthought?
Date: Tue, 13 Jul 2004 13:09:28 +0100	[thread overview]
Message-ID: <008501c468d2$405d8c70$161b14ac@boromir> (raw)
In-Reply-To: 20040712172458.2659db52.akpm@osdl.org

[...]
> Please double-check that there are no priority inversion problems and that
> the application is correctly setting the scheduling policy and that it is
> mlocking everything appropriately.

I don't think it is currently possible to have cooperating threads with
different priorities without priority inversion when using a mutex to
serialize access to shared data; and using a mutex is in fact the only portable
way to do that...

Thus, the fact that Linux does not support protocols to prevent priority
inversion (please correct me if I am wrong) kind of suggests that supporting
realtime applications is not considered very important.

It is often heard in the Linux audio community that mutexes are not realtime
safe and a lock-free ringbuffer should be used instead. Using such a lock-free
ringbuffer requires non-standard atomic integer operations and does not
guarantee memory synchronization (and should probably not perform
significantly better than a decent mutex implementation) and is thus not
portable.

--ms



  parent reply	other threads:[~2004-07-13 11:11 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-12 20:45 desktop and multimedia as an afterthought? Albert Cahalan
2004-07-12 23:54 ` Paul Davis
2004-07-13  0:18   ` Con Kolivas
2004-07-13  1:11     ` Paul Davis
2004-07-13  3:25     ` Florin Andrei
2004-07-13  0:24   ` Andrew Morton
2004-07-13  1:49     ` Thomas Charbonnel
2004-07-13 10:22       ` Andrew Morton
2004-07-13 11:01         ` Thomas Charbonnel
2004-07-13  3:22     ` Florin Andrei
2004-07-13  8:30     ` Takashi Iwai
2004-07-13 11:09     ` Kasper Sandberg
2004-07-13 12:09     ` Martijn Sipkema [this message]
2004-07-13 14:55       ` [linux-audio-dev] " Paul Davis
2004-07-13 22:37         ` Martijn Sipkema
2004-07-13 22:31           ` Fons Adriaensen
2004-07-13 19:12       ` Bill Huey
2004-07-13 20:00         ` Lee Revell
2004-07-13 22:44         ` Martijn Sipkema
2004-07-13 22:08           ` Bill Huey
2004-07-13 23:37             ` Martijn Sipkema

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