From owner-freebsd-multimedia@FreeBSD.ORG Thu Apr 22 05:48:12 2010 Return-Path: Delivered-To: freebsd-multimedia@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E96571065670 for ; Thu, 22 Apr 2010 05:48:11 +0000 (UTC) (envelope-from areilly@bigpond.net.au) Received: from nskntqsrv01p.mx.bigpond.com (nskntqsrv01p.mx.bigpond.com [61.9.168.231]) by mx1.freebsd.org (Postfix) with ESMTP id 6DFC48FC19 for ; Thu, 22 Apr 2010 05:48:11 +0000 (UTC) Received: from nskntotgx01p.mx.bigpond.com ([124.188.161.100]) by nskntmtas06p.mx.bigpond.com (InterMail vM.7.05.02.08 201-2174-114-118-20080528) with ESMTP id <20100422042930.YQHN1419.nskntmtas06p.mx.bigpond.com@nskntotgx01p.mx.bigpond.com>; Thu, 22 Apr 2010 04:29:30 +0000 Received: from duncan.reilly.home ([124.188.161.100]) by nskntotgx01p.mx.bigpond.com with ESMTP id <20100422042929.BNAC1945.nskntotgx01p.mx.bigpond.com@duncan.reilly.home>; Thu, 22 Apr 2010 04:29:29 +0000 Date: Thu, 22 Apr 2010 14:29:29 +1000 From: Andrew Reilly To: Roman Divacky Message-ID: <20100422042929.GA79075@duncan.reilly.home> References: <20100421152338.GA77210@freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100421152338.GA77210@freebsd.org> User-Agent: Mutt/1.4.2.3i X-Authentication-Info: Submitted using SMTP AUTH LOGIN at nskntotgx01p.mx.bigpond.com from [124.188.161.100] using ID areilly@bigpond.net.au at Thu, 22 Apr 2010 04:29:29 +0000 X-RPD-ScanID: Class unknown; VirusThreatLevel unknown, RefID str=0001.0A150202.4BCFD0A9.016D,ss=1,fgs=0 X-SIH-MSG-ID: qhE6FtHuXAD+xDJw0jPvNAJ+xA/u8yI74J0WRdJsoQQZSkfduMHeU677NrMwgcz21jxcNh6PPGgqYKz0X4/QsuM= Cc: freebsd-multimedia@freebsd.org, Alexander Best , freebsd-current@FreeBSD.org Subject: Re: [CFT]: ClangBSD is selfhosting, we need testers now X-BeenThere: freebsd-multimedia@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Multimedia discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Apr 2010 05:48:12 -0000 On Wed, Apr 21, 2010 at 05:23:38PM +0200, Roman Divacky wrote: > On Wed, Apr 21, 2010 at 05:20:57PM +0200, Alexander Best wrote: > > i might have stumbled upon a problem with clang. i've compiled a kernel from > > the clang branch using `make kernel INSTKERNNAME=clang` and booted from it. > > i'm now experiencing audio problems with mp3s and certain video files. > > playback is awfully slow and the audio output gets distorted massively. `top` > > however reports no high cpu load and `vmstat -i` doesn't report anything > > unusual either. > > > > this problem doesn't occur with a regular gcc-kernel. > > > > both kernels are running under a regular (gcc) world. > > > > i thought it might be a problem with acpi, but disabling acpi > > (hint.acpi.0.disabled=1) gives me a system freeze. > > I've heard about this problem but did not manage to reproduce that. > > can you try to bisect what file is being miscompiled? ie. compile > half of the kernel with gcc and half with clang and bisect this > way to a single file. The FreeBSD sound subsystem has a sample-rate converter built into the feeder that (from a cursory look) is probably quite carefully tweaked to be able to perform well (or at all). I've added -multimedia to the CC line, because they're the guys who are going to know the details. It's possible that some GCC-specific manifest constants are being tested-for, with sub-optimal fall-back code being run, instead. In the mean-time, Alexander, are there any sound-related sysctls that you can tweak so that the audio playback that you're doing does *not* involve sample rate conversion? Cheers, -- Andrew