From owner-freebsd-questions@FreeBSD.ORG Wed Jul 28 05:23:36 2010 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BE0551065674 for ; Wed, 28 Jul 2010 05:23:36 +0000 (UTC) (envelope-from debackerl@gmail.com) Received: from mail-fx0-f54.google.com (mail-fx0-f54.google.com [209.85.161.54]) by mx1.freebsd.org (Postfix) with ESMTP id 4B37F8FC16 for ; Wed, 28 Jul 2010 05:23:35 +0000 (UTC) Received: by fxm13 with SMTP id 13so1041381fxm.13 for ; Tue, 27 Jul 2010 22:23:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:mime-version:received:in-reply-to :references:from:date:message-id:subject:to:cc:content-type; bh=vTfao7jJZxdGAfaOnvORgw/2nhLAIcymplYQtc637MQ=; b=h7CQkbyWCNnhWDYX6HkzQSPchOaz6EPi8ITlMR0sOfsie1NNAFDeRKR+IB5VjfdP4M Cbn3RAXLOIQ5VhnOsbsjWplHNmNVnXAyplR0HX4BMjJ1WCL1XDx2+qyw2kr9Lru4q9y7 ZM++F3MPLHw10w3rryinoQ2xfhvmXqTQcqByc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=nkbkjivq2JRxACLf+QsyHk5X2Sb8JqKDBS2iaZL5H3W/pvsyJqEf0PHaaLR2wGkrx3 gQ/elEVGXMwsimhC9dEgzsH+U77yATfk9HozDQtOnOUyhZIMvPnS9rIRtnGZBhRwgaZ8 R77621QcvObJAh3oGBIuKZZHwADjWIub/EbmU= Received: by 10.223.117.194 with SMTP id s2mr9169931faq.57.1280294614995; Tue, 27 Jul 2010 22:23:34 -0700 (PDT) MIME-Version: 1.0 Received: by 10.223.115.193 with HTTP; Tue, 27 Jul 2010 22:23:14 -0700 (PDT) In-Reply-To: References: From: Debacker Date: Wed, 28 Jul 2010 07:23:14 +0200 Message-ID: To: Adam Vande More Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: Andrew Gould , freebsd-questions@freebsd.org Subject: Re: Real-Time Video Recording (ionice equivalent) X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Jul 2010 05:23:36 -0000 On Tue, Jul 27, 2010 at 10:52 PM, Adam Vande More wrote: > On Tue, Jul 27, 2010 at 2:29 PM, Debacker wrote: > >> Of course, just like you could put real-time processes in one CPU, and >> normal processes on another to avoid implement complex algorithms. >> While your solution is pragmatic, I would like to know if there are >> "clean" >> ways to do it. If not, this would be a documented use case to why would >> anyone actually need an I/O scheduler. >> > > First, top-posting on this list is considered rude. Please don't do that. > Sorry, I didn't want to hurt anyone, I just didn't know the traditions of this mailing-list, I'll be careful from now on. If you're running 8.1, try "man gsched", it's new and haven't tried it. > Excellent! I can use 8.1, it's for a new setup. > Other than that, the traditional way would be to give higher priority to > the process that needs it. It's the poor man's io scheduler, but it > generally does work well. > > If you have lots of concurrent io and are running a UFS file-system, > consider running gjournal as it scales those requests better. > > Also if you're hardware supports it, NCQ is available via the ahci and a > few other modules. It will make your requests more efficient. > Thank you for your tips. I'm happy that I will be able to use FreeBSD for this job. Laurent Debacker