From: Peter Zijlstra <peterz@infradead.org>
To: raz ben yehuda <raziebe@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>,
linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Lior Brafman <LBrafman@manz.com>,
Torsten Scherer <TScherer@manz.com>,
Rasty Slutsker <RSlutsker@manz.com>
Subject: Re: Subject: [PATCH 2/2] priority System V Semaphores
Date: Thu, 22 Dec 2011 09:59:12 +0100 [thread overview]
Message-ID: <1324544352.24803.9.camel@twins> (raw)
In-Reply-To: <1324500515.5467.18.camel@raz>
On Wed, 2011-12-21 at 22:48 +0200, raz ben yehuda wrote:
> Vxworks is the use case. And there are plenty of companies with
> vxWorks software and in i believe they will migrate sooner or later to
> PreemptRT. My current company uses old wrapper software that implements
> vxWorks semaphores as system V semaphores. vxWorks semaphores have a priority
> feature which is widely used.
> I will probably change it some time in the future to posix semaphores , but posix
> semaphores are implemented in glibc with futexes and atomic ops and i rather
> mess with kernel and not glibc. funny , but true. glibc is harder.
Semaphores are a fscking trainwreck for real-time programming. Don't use
them, full stop. If you do, you're doing it wrong, it's really that
simple.
Use PI mutexes, which are already fully supported in glibc, no extra
patching needed.
Full NAK for any and all priority fudging for any semaphore
implementation.
next prev parent reply other threads:[~2011-12-22 8:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-20 22:23 Subject: [PATCH 2/2] priority System V Semaphores raz ben yehuda
2011-12-21 18:31 ` Manfred Spraul
2011-12-21 20:48 ` raz ben yehuda
2011-12-22 3:58 ` Steven Rostedt
2011-12-22 8:59 ` Peter Zijlstra [this message]
2011-12-22 13:00 ` Raz
2011-12-22 14:00 ` Peter Zijlstra
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