From owner-freebsd-current@FreeBSD.ORG Sun Dec 18 10:34:41 2011 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 652C6106564A; Sun, 18 Dec 2011 10:34:41 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-vx0-f182.google.com (mail-vx0-f182.google.com [209.85.220.182]) by mx1.freebsd.org (Postfix) with ESMTP id 9BEF08FC13; Sun, 18 Dec 2011 10:34:40 +0000 (UTC) Received: by vcbfk1 with SMTP id fk1so5897013vcb.13 for ; Sun, 18 Dec 2011 02:34:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=s6kIoTrilkDgvCqa7CBeAusmCWmQmTPCl4RVMTG7W7o=; b=odf2/KQtLGeZG11305gEP1KiG7+ubW+oPsc0+7Eh8JLQguv73H4Ua8edlUNJ1tn3Ls hdqo8DlYC7pwZkaRQP3wBMZf+fswsbnnmZ0+DEwryKtpV3YdRC0aQLf6dR9SSXKf4uFk cVdOKApp/s6YE6A3yN8lV+o80IFCotsTmKyKA= MIME-Version: 1.0 Received: by 10.220.151.204 with SMTP id d12mr7411703vcw.40.1324204479840; Sun, 18 Dec 2011 02:34:39 -0800 (PST) Sender: adrian.chadd@gmail.com Received: by 10.52.26.50 with HTTP; Sun, 18 Dec 2011 02:34:39 -0800 (PST) In-Reply-To: <20111218102600.GA44118@freebsd.org> References: <4EE1EAFE.3070408@m5p.com> <4EE22421.9060707@gmail.com> <4EE6060D.5060201@mail.zedat.fu-berlin.de> <4EE69C5A.3090005@FreeBSD.org> <20111213104048.40f3e3de@nonamehost.> <20111213090051.GA3339@vniz.net> <4EED5200.20302@cran.org.uk> <20111218164924.L64681@sola.nimnet.asn.au> <20111218075241.GA45367@vniz.net> <20111218102401.GA42627@freebsd.org> <20111218102600.GA44118@freebsd.org> Date: Sun, 18 Dec 2011 02:34:39 -0800 X-Google-Sender-Auth: uHpK_GNrw2hgPHGTKxPMp-CpkzM Message-ID: From: Adrian Chadd To: Alexander Best Content-Type: text/plain; charset=ISO-8859-1 X-Mailman-Approved-At: Sun, 18 Dec 2011 22:02:50 +0000 Cc: Bruce Cran , Ivan Klymenko , Doug Barton , Ian Smith , "O. Hartmann" , Current FreeBSD , freebsd-stable@freebsd.org, freebsd-performance@freebsd.org Subject: Re: SCHED_ULE should not be the default X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 18 Dec 2011 10:34:41 -0000 The trouble is that there's lots of anecdotal evidence, but noone's really gone digging deep into _their_ example of why it's broken. The developers who know this stuff don't see anything wrong. That hints to me it may be something a little more creepy - as an example, the interplay between netisr/swi/taskqueue/callbacks and such. It may be that something is being starved that isn't obviously obvious. It's just a stab in the dark, but it sounds somewhat plausible based on what I've seen ULE do in my network throughput hacking. I applaud reppie for trying to make it as easy as possible for people to use KTR to provide scheduler traces for him to go digging with, so please, if you have these issues and you can absolutely reproduce them, please follow his instructions and work with him to get him what he needs. Adrian (wow, lots of personal pronouns packed into one sentence. It must be sleep time.)