From owner-freebsd-current@FreeBSD.ORG Thu May 7 10:04:48 2009 Return-Path: Delivered-To: Current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 912571065670 for ; Thu, 7 May 2009 10:04:48 +0000 (UTC) (envelope-from astrodog@gmail.com) Received: from fk-out-0910.google.com (fk-out-0910.google.com [209.85.128.187]) by mx1.freebsd.org (Postfix) with ESMTP id 1F40A8FC1B for ; Thu, 7 May 2009 10:04:47 +0000 (UTC) (envelope-from astrodog@gmail.com) Received: by fk-out-0910.google.com with SMTP id f33so349264fkf.11 for ; Thu, 07 May 2009 03:04:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=tOQlZKJm6xUt9ZnELW597VJypUAtIhL92HAvnbrINBw=; b=RNMNqG4IrTzAf1Y2pRmtNQvnM6itwadn606iDyqGL1t+2FFtfcf/9IsgvJgvetMVEV GMkmBzDfVEZKgXUCbU7fA0PqM7qvOsO/q/XlxnuISBPvPoqQ3qawT2y5HrDGqMdr+B+m xFUqlaBMWcwq5fJ3bKfgsVId9mKM6ddYi8mDM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=F6Oi3GBKkVhiHIRG90+AcOC1VkEUABV0J9KKCP64u+k+1cKGWgPTu+lwju/K19jaLr +yACqYTzUl23OBLxluyPtf4/yUubQe84Q64aKA+Ad9RltT6dZtOtaXEbft+VpVz2bZJn 28YXcc/WBW7JyfU88b2HyCwXNtornOG0DBuzQ= MIME-Version: 1.0 Received: by 10.223.103.133 with SMTP id k5mr1480866fao.23.1241688970263; Thu, 07 May 2009 02:36:10 -0700 (PDT) In-Reply-To: <758865.1091.qm@web63907.mail.re1.yahoo.com> References: <758865.1091.qm@web63907.mail.re1.yahoo.com> Date: Thu, 7 May 2009 04:36:10 -0500 Message-ID: <2fd864e0905070236m4ff62796y3839a1d21c1ed610@mail.gmail.com> From: Astrodog To: barney_cordoba@yahoo.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: pluknet , "Current@freebsd.org" Subject: Re: Hypertherading 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: Thu, 07 May 2009 10:04:48 -0000 The big thing I've seen in all of the tests of HT is that it's incredibly dependent on the type of load one's trying to run. Loads which consist largely of mathematical calculations and very latency-sensitive loads seem to be hurt by it, and desktop loads seem to see either nothing, or a mild improvement. The scheduler is better at handling this kind of decision than the CPU is, in most cases. (To say nothing of the annoyance HT causes for the scheduler, imo) JeffR can probably explain what actually happens with HT enabled (as far as scheduling decisions go) better than I can. --- Harrison