From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262490AbULOURH (ORCPT ); Wed, 15 Dec 2004 15:17:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262491AbULOURG (ORCPT ); Wed, 15 Dec 2004 15:17:06 -0500 Received: from gprs215-213.eurotel.cz ([160.218.215.213]:63616 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S262490AbULOUQj (ORCPT ); Wed, 15 Dec 2004 15:16:39 -0500 Date: Wed, 15 Dec 2004 21:16:18 +0100 From: Pavel Machek To: Gene Heskett Cc: linux-kernel@vger.kernel.org, Andrea Arcangeli , Zwane Mwaikambo , Con Kolivas Subject: Re: USB making time drift [was Re: dynamic-hz] Message-ID: <20041215201618.GA5797@elf.ucw.cz> References: <20041213002751.GP16322@dualathlon.random> <200412142159.23488.gene.heskett@verizon.net> <20041215091741.GA16322@dualathlon.random> <200412151144.38785.gene.heskett@verizon.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200412151144.38785.gene.heskett@verizon.net> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > >> Which way? I was running quite fast here, several minutes an > > > >In the future, if I disable the logic it goes in the past at the > > same speed it was previously going in the future. > > > >> hour, then I discovered the tickadj command, found its default > >> was 10000, and started reducing it. At 9926, I'm staying within > >> a sec an hour now. I have no idea when this started, I didn't > > > >That seems quite an hack, note I did an hack too and it make the > > drift much smaller (it gets manageable). But our modifications are > > wrong. > > > >The point is that this didn't happen with HZ=100, so it's not that > >tickadj is wrong, it's the tick adjustment code that doesn't work. > > > The HZ=1000 is the culprit? > > >You may want to recompile your kernel with HZ=100 and verify it goes > >away (I didn't verify myself, but I verified the max irq latency I > > get is 4msec, and in turn I'm sure HZ=100 would fix it > > Humm, that might also reduce the obviousness of the irq activity in > the audio, there are times when I can hear it very plainly while a > low level audio src is in use, like the sub-millivolt levels that come > out of my Hauppauge WinTV-GO+FM card. I keep having to turn the Try idle=poll. That noise may be commig from cpu switching between powersave and full speed. Pavel -- People were complaining that M$ turns users into beta-testers... ...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!