From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15060 invoked by alias); 11 Feb 2002 16:39:07 -0000 Mailing-List: contact ecos-discuss-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@sources.redhat.com Received: (qmail 15006 invoked from network); 11 Feb 2002 16:39:04 -0000 Received: from unknown (HELO pink.pearsoft.ch) (195.141.66.36) by sources.redhat.com with SMTP; 11 Feb 2002 16:39:04 -0000 Received: from bulldozer.hq.acn-group.ch (dyna-ne-18.dial.eunet.ch [193.72.12.241]) by pink.pearsoft.ch (8.11.2/(Pearsoft Technologies AG 2001.20.14)) with ESMTP id g1BGd2Q09479; Mon, 11 Feb 2002 17:39:02 +0100 Received: from localhost ([127.0.0.1]) by halftrack.hq.acn-group.ch with esmtp (Exim 3.34 #1 (Debian)) id 16aJSw-0004xJ-00; Mon, 11 Feb 2002 17:38:06 +0100 From: Robin Farine To: "Woller, Thomas" Cc: eCos users In-Reply-To: <973C11FE0E3ED41183B200508BC7774C022FBA8D@csexchange.crystal.cirrus.com> References: <973C11FE0E3ED41183B200508BC7774C022FBA8D@csexchange.crystal.cirrus.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Evolution/1.0 (Preview Release) Date: Mon, 11 Feb 2002 08:39:00 -0000 Message-Id: <1013445486.26972.4.camel@halftrack> Mime-Version: 1.0 Subject: RE: [ECOS] cyg_semaphore_post X-SW-Source: 2002-02/txt/msg00226.txt.bz2 On Mon, 2002-02-11 at 16:10, Woller, Thomas wrote: > we are also wondering how to handle the non-priority based (ie. > FIFO based) waiting under eCos. when there are a series of > threads waiting on the same semaphore, we basically want the > highest priority thread to run, NOT the first one that happened > to wait on the semaphore. some of our current s/w on another > RTOS that we are porting over currently supports both FIFO and > priority based semaphores/mutexes. so we think that core > modifications are the only option we have. we could just allow > the lower priority threads, that are first on the FIFO, to cycle > out with context switches at the most every system tick. not sure > if this is going to be too much latency for the higher priority > thread though, we'll have to test and see. > tom > You might try a mutex, a condition variable and an appropriate priority inversion protection protocol instead of a counting semaphore. [snip] Robin Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos and search the list archive: http://sources.redhat.com/ml/ecos-discuss