From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marco Stornelli Subject: Re: UIO - interrupt performance Date: Mon, 20 Oct 2008 13:55:41 +0200 Message-ID: <48FC71BD.9070703@coritel.it> References: <5958B8D7916AB84781FE0E7B57C218CB75AB98@306900ANEX2.global.avaya.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5958B8D7916AB84781FE0E7B57C218CB75AB98@306900ANEX2.global.avaya.com> Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: "Douglas, Jim (Jim)" Cc: Embedded Linux mailing list I quite agree with Ben and Christian. I think UIO drivers are usable for simple devices, I think they aren't mature (will it ever be?) to use it with complicated devices or with strict requirement. Regards, Douglas, Jim (Jim) ha scritto: > We are contemplating porting a large number of device drivers to Linux. > The pragmatic solution is to keep them in user mode (using the UIO > framework) where possible ... they are written in C++ for a start. > > The obvious disadvantages of user mode device drivers are security / > isolation. The main benefit is ease of development. > > Do you know what the *technical* disadvantages of this approach might > be? I am most concerned about possible impact on interrupt handling. > > For example, I assume the context switching overhead is higher, and that > interrupt latency is more difficult to predict? > > --jim douglas > Avaya UK, Registered in England and Wales under Registered Number > 3049861, Registered Address: Avaya House, Cathedral Hill, Guildford, > Surrey, GU2 7YL. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-embedded" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Marco Stornelli Embedded Software Engineer CoRiTeL - Consorzio di Ricerca sulle Telecomunicazioni http://www.coritel.it marco.stornelli@coritel.it +39 06 72582838