From owner-freebsd-performance@FreeBSD.ORG Wed Oct 24 19:29:36 2007 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 943FF16A417 for ; Wed, 24 Oct 2007 19:29:36 +0000 (UTC) (envelope-from josh.carroll@gmail.com) Received: from py-out-1112.google.com (py-out-1112.google.com [64.233.166.177]) by mx1.freebsd.org (Postfix) with ESMTP id 51BAF13C48A for ; Wed, 24 Oct 2007 19:29:36 +0000 (UTC) (envelope-from josh.carroll@gmail.com) Received: by py-out-1112.google.com with SMTP id u77so318523pyb for ; Wed, 24 Oct 2007 12:29:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=mA9bNu/H0Dmg6317CEGakFLfGL8DrIvZ58xXlfSWJxE=; b=RdvpwG8ILT0FjgWsHMyNJCjsPCARi8FJXbPVhCA4aha05KC5Bl0KHG04s/v2lr1vQsNA7lCE5xTml7pDk3/jyUx3TNqHb8GgCNKuF/8C8fqzIyfqd+f388hfGFP1ehCKED4CY268Q/WdOjRNVsIfSPMH/w6UxWbhcih89QZKQkA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:reply-to:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=okbE1h63dn6c0T/QgGvlbDvXqEloHBrwXn4u2VyvbW2AjWDJI4ShxOxGkm4XEm+uXQMjjCk+vSdmVeILzCPYByepGzhSih8OsaBewb/0eCIa3u+qWpB77Eps+t1gwnioFSTo2UpaqJcY0tE1xrrb6MwfS7OSRnuDhBb5RDiKC5g= Received: by 10.35.14.18 with SMTP id r18mr1050015pyi.1193254164329; Wed, 24 Oct 2007 12:29:24 -0700 (PDT) Received: by 10.35.117.12 with HTTP; Wed, 24 Oct 2007 12:29:24 -0700 (PDT) Message-ID: <8cb6106e0710241229i12852d8cq436f4c955ac62c56@mail.gmail.com> Date: Wed, 24 Oct 2007 15:29:24 -0400 From: "Josh Carroll" To: "Jeff Roberson" In-Reply-To: <20071024111105.M598@10.0.0.1> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <8cb6106e0710230902x4edf2c8eu2d912d5de1f5d4a2@mail.gmail.com> <20071024111105.M598@10.0.0.1> Cc: remy.nonnenmacher@activnetworks.com, freebsd-performance@freebsd.org Subject: Re: ULE vs. 4BSD in RELENG_7 X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: josh.carroll@gmail.com List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 19:29:36 -0000 > Your tests with ffmpeg threads vs processes probably is triggering more > context switches due to lock contention in the kernel in the threads case. > This is also likely the problem with some super-smack tests. On each > context switch 4BSD has an opportunity to perfectly balance the CPUs. ULE > does not because it's too costly and hinders other workloads. Thanks for the response Jeff, I appreciate it. Is this something that the scheduler can recognize and auto-tune itself for? E.g. have it recognize the scenario differences and do what 4BSD is doing for cases such as ffmpeg and what ULE otherwise does in other circumstances? I guess this would not come without its own overhead, which might defeat the purpose anyway. > I don't doubt that we can improve things further. It will just have to > wait for another few weeks before I'm able to do much about it. Thanks again, I do appreciate your work and help. So you're anticipating nothing can be done at all, or did you mean at the moment until you get your equipment back and get settled? Or is this something that would need to be looked at in -current rather than 7-STABLE? Regards, Josh