From owner-freebsd-questions@FreeBSD.ORG Tue Jul 27 20:52:07 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 31B0E106566B for ; Tue, 27 Jul 2010 20:52:07 +0000 (UTC) (envelope-from amvandemore@gmail.com) Received: from mail-gx0-f182.google.com (mail-gx0-f182.google.com [209.85.161.182]) by mx1.freebsd.org (Postfix) with ESMTP id DC6668FC08 for ; Tue, 27 Jul 2010 20:52:06 +0000 (UTC) Received: by gxk24 with SMTP id 24so1775490gxk.13 for ; Tue, 27 Jul 2010 13:52:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:cc:content-type; bh=oZCmRnJs8Yo3ec75GnkMNI5P9/jA1Iwh0hbD2e8uTVQ=; b=wtqwqyVMR7bWMFgSChCVDmzufsYBV3CR9+FbJhDJlcV5/jk+3A2T08G0poMnK2+iO+ mjQoHRNM787vD4Qb5jdCA0iOyVaCktGum0S2euZm25FXTAtHkCh9T3K+6iq2yVE+0JvN sqndMGolMJ6lNdTrbVdTBYmToEoGt6X1PcRw4= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=lAEEGQA6/gviLSXQZgX6APNu6z03d6M2CWYj/CCnmRx/0mdQlkHGnSFMZS5a4MJO8W xUISElwO3jwf0ZEorJsPUuJn8sDXQnIGFqZa4BqLByUSOhBicnxU9/fYQxNeoX8s8Qbc KZIDVTFaIqv35cQutsWNog2dWdC9Psjt4oZhI= MIME-Version: 1.0 Received: by 10.150.73.38 with SMTP id v38mr11764163yba.430.1280263926316; Tue, 27 Jul 2010 13:52:06 -0700 (PDT) Received: by 10.151.107.12 with HTTP; Tue, 27 Jul 2010 13:52:06 -0700 (PDT) In-Reply-To: References: Date: Tue, 27 Jul 2010 15:52:06 -0500 Message-ID: From: Adam Vande More To: Debacker 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: Tue, 27 Jul 2010 20:52:07 -0000 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. If you're running 8.1, try "man gsched", it's new and haven't tried it. 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. -- Adam Vande More