From owner-freebsd-stable@FreeBSD.ORG Sun Jul 20 23:59:47 2014 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 3E17C260 for ; Sun, 20 Jul 2014 23:59:47 +0000 (UTC) Received: from qmta02.emeryville.ca.mail.comcast.net (qmta02.emeryville.ca.mail.comcast.net [IPv6:2001:558:fe2d:43:76:96:30:24]) by mx1.freebsd.org (Postfix) with ESMTP id 1D9DC2B3A for ; Sun, 20 Jul 2014 23:59:47 +0000 (UTC) Received: from omta08.emeryville.ca.mail.comcast.net ([76.96.30.12]) by qmta02.emeryville.ca.mail.comcast.net with comcast id UnQ81o0080FhH24A2nzm1u; Sun, 20 Jul 2014 23:59:46 +0000 Received: from jdc.koitsu.org ([69.181.136.108]) by omta08.emeryville.ca.mail.comcast.net with comcast id Unzl1o00b2LW5AV8Unzmew; Sun, 20 Jul 2014 23:59:46 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id B9A621744B1; Sun, 20 Jul 2014 16:59:45 -0700 (PDT) Date: Sun, 20 Jul 2014 16:59:45 -0700 From: Jeremy Chadwick To: hiren panchasara Subject: Re: Consistently "high" CPU load on 10.0-STABLE Message-ID: <20140720235945.GA90603@icarus.home.lan> References: <20140720062413.GA56318@icarus.home.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20140121; t=1405900786; bh=cGMuYzoZadN3GhiH0zUPK1pSMkVC47w9B2PpvD/8ZVM=; h=Received:Received:Received:Date:From:To:Subject:Message-ID: MIME-Version:Content-Type; b=nahkbyJtVToJZJ/qoixJi+ZeXKeXwi5h4CiODzlvEBkVO4MqfJJ9YLMNxr2pWYIJo bqs91bP77C2DF5CuzAx7PbA8ezgZ3x1MBO8Mb1m/dberxuawyyAi1dUlpKAsfVLtKf CqcuoABElahcBm5NkV50DEuaX83DWD27H7laYzgUSkYQShftgQ7eWOsXqoiX5yhWuR 6Cqczz2W4lYfapkMOi4sFSBcSnJiKVgEiWyWrgWGLjiXDxR3/zIz6K3AAmffHcnrms kGZR7y4OPUWwS71eCJw4eyY1HUzAIFoLWbC+U8D9HLAHCvk+j+tZ6lx7NeyRRNbRT8 wd5YKO1DvKrcQ== Cc: FreeBSD Stable Mailing List X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 20 Jul 2014 23:59:47 -0000 On Sun, Jul 20, 2014 at 04:36:10PM -0700, hiren panchasara wrote: > On Sat, Jul 19, 2014 at 11:24 PM, Jeremy Chadwick wrote: > > (Please keep me CC'd as I'm not subscribed to freebsd-stable@) > [skip] > > > > I do have DTrace enabled/built on this box but I have absolutely no clue > > how to go about profiling things. For example maybe output of this sort > > would be helpful (but I've no idea how to get it): > > > > http://lists.freebsd.org/pipermail/freebsd-stable/2014-July/079276.html > > You can probably use hotkernel or something similar? > http://www.freebsd.org/doc/handbook/dtrace-using.html Yeah, I've given that a try. I think all that script does, in layman's terms, is count the number of occurrences of a kernel function/symbol being called. If there was a single kernel function being called repeatedly in excess then it would show up there, but if it's more like a mutex being held for a long time I don't think hotkernel would show this. Meaning: it doesn't actually indicate "how much" time something took, just the number of times something was run. I think this was why Adrian was advocating KTR. procsystime might be more useful if I had reason to think it was a userland process, but the jury's still out on that one (I haven't seen anything userland show up in top that would indicate CPU usage, which is why I'm more suspicious of the kernel). -- | Jeremy Chadwick jdc@koitsu.org | | UNIX Systems Administrator http://jdc.koitsu.org/ | | Making life hard for others since 1977. PGP 4BD6C0CB |