From owner-freebsd-hackers@FreeBSD.ORG Tue Aug 31 08:29:22 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B48E610656BA; Tue, 31 Aug 2010 08:29:22 +0000 (UTC) (envelope-from gljennjohn@googlemail.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 A8CC18FC1E; Tue, 31 Aug 2010 08:29:21 +0000 (UTC) Received: by fxm4 with SMTP id 4so4389960fxm.13 for ; Tue, 31 Aug 2010 01:29:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:received:received:date:from:to:cc:subject :message-id:in-reply-to:references:reply-to:x-mailer:mime-version :content-type:content-transfer-encoding; bh=FF95OBHJW6mUZesQaTUqkozxIhs10zB20SbqHLjB9Cg=; b=I/yLbWT1ulDHp+vbI67Ds2tn/Iy9Pj8G+Diswwbv9dyK1lqvUgnX1/JsZyXJtctg4q 3rgkS6aWmfKnG0O8o9qRHTcQenNe8kOO1I8eAGHI+fHZcqCPO1SQwKfOdhr+XLdytaA1 vEH9OG/GwBvt1mcOUbnySHRc++FJF68vCV4w4= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=date:from:to:cc:subject:message-id:in-reply-to:references:reply-to :x-mailer:mime-version:content-type:content-transfer-encoding; b=SxojT1+f1VxkEqYTd1JFZK/xo6NalzaFhydxZZs7W+HdyNIM/t4zCmenWTgsQlHhRs 5tatPmT2ORJ1+dhpSezkXscdlpMbmM9jsfk4WHtkYmu7oVZhsa3OxSfcDf51A1sw6rro 3tnsfMsv19Bqs8rejKdNjEI9aaEV6D1s6n1w0= Received: by 10.223.126.19 with SMTP id a19mr4918608fas.88.1283243360740; Tue, 31 Aug 2010 01:29:20 -0700 (PDT) Received: from ernst.jennejohn.org (p578E3809.dip.t-dialin.net [87.142.56.9]) by mx.google.com with ESMTPS id 2sm3832710faz.14.2010.08.31.01.29.19 (version=TLSv1/SSLv3 cipher=RC4-MD5); Tue, 31 Aug 2010 01:29:20 -0700 (PDT) Date: Tue, 31 Aug 2010 10:29:18 +0200 From: Gary Jennejohn To: gljennjohn@googlemail.com Message-ID: <20100831102918.4f5404cc@ernst.jennejohn.org> In-Reply-To: <20100830121148.11926306@ernst.jennejohn.org> References: <4C7A5C28.1090904@FreeBSD.org> <20100830110932.23425932@ernst.jennejohn.org> <4C7B82EA.2040104@FreeBSD.org> <20100830121148.11926306@ernst.jennejohn.org> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.18.7; amd64-portbld-freebsd9.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: freebsd-hackers@freebsd.org, Alexander Motin , FreeBSD-Current Subject: Re: One-shot-oriented event timers management X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: gljennjohn@googlemail.com List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 Aug 2010 08:29:22 -0000 On Mon, 30 Aug 2010 12:11:48 +0200 Gary Jennejohn wrote: > On Mon, 30 Aug 2010 13:07:38 +0300 > Alexander Motin wrote: > > > Gary Jennejohn wrote: > > > Hmm. I applied your patches and am now running the new kernel. But I > > > only installed the new kernel and didn't do make buildworld installworld. > > > > > > Mu systat -vm 1 doesn't look anything like yours. I'm seeing about 2300 > > > interrupts per second and most of those are coming from the hpet timers: > > > > > > 1122 hpet0:t0 > > > 1124 hpet0:t1 > > > > It means 1000Hz of hardclock (hz) events mixed with 127Hz of statclock > > (stathz) events. HPET timer here works in one-shot mode handling it. > > > > > So, what else did you do to reduce interrupts so much? > > > > > > Ah, I think I see it now. My desktop has only C1 enabled. Is that it? > > > Unfortunately, it appears that only C1 is supported :( > > > > Yes, as I have said, at this moment empty ticks skipped only while CPU > > is in C2/C3 states. In C1 state there is no way to handle lost events on > > wake up. While it may be not very dangerous, it is not very good. > > > > Too bad. I'd say that systems which are limited to C1 don't benefit > much (or not at all) from your changes. > OK, this is purely anecdotal, but I'll report it anyway. I was running pretty much all day with the patched kernel and things seemed to be working quite well. Then, after about 7 hours, everything just stopped. I had gkrellm running and noticed that it updated only when I moved the mouse. This behavior leads me to suspect that the timer interrupts had stopped working and the mouse interrupts were causing processes to get scheduled. Unfortunately, I wasn't able to get a dump and had to hit reset to recover. As I wrote above, this is only anecdotal, but I've never seen anything like this before applying the patches. -- Gary Jennejohn