From owner-freebsd-doc@FreeBSD.ORG Thu Apr 23 18:39:07 2009 Return-Path: Delivered-To: doc@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EBE101065670 for ; Thu, 23 Apr 2009 18:39:07 +0000 (UTC) (envelope-from josh.m.ulrich@gmail.com) Received: from rv-out-0506.google.com (rv-out-0506.google.com [209.85.198.228]) by mx1.freebsd.org (Postfix) with ESMTP id C57BC8FC14 for ; Thu, 23 Apr 2009 18:39:07 +0000 (UTC) (envelope-from josh.m.ulrich@gmail.com) Received: by rv-out-0506.google.com with SMTP id l9so196340rvb.3 for ; Thu, 23 Apr 2009 11:39:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:message-id:subject :from:to:content-type:content-transfer-encoding; bh=vV5KBfpemA3hnCEHN9aD0bWhM0C2MGaVWrrDpzVBHgI=; b=T9YLuiKU7UP4NFDEyrGkqbruIYTC9ljXvRuy/7cMYg7o527ZdUQ8EG1Kxf/gCqFhbf +1pf2ynFhjLBOMjeZAfyhknA29jHbiUms+RLYfRE584WY3g2E3etZq7agVuXM5Azi9J9 Ph1E73GR0mQA63lgvx6KBIaRFa/1CmkuQzFz0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type :content-transfer-encoding; b=cjtfsWRJael+lPae90VwV64RMS0w3D52jK4U8myCBfuxEHROhPlIGGTQa+lksdUa/S bre+g39CR5CBcsnFrz7K1/Hw3GS5eMCftaATCMILUy7TuqLbbxIy9h7EfwavqJn9JgKA BlcZBiDThZuAhzcw3hcwYOodVDlF/Lil8LXJM= MIME-Version: 1.0 Received: by 10.142.157.9 with SMTP id f9mr434337wfe.59.1240510078534; Thu, 23 Apr 2009 11:07:58 -0700 (PDT) Date: Thu, 23 Apr 2009 13:07:58 -0500 Message-ID: <8cca69990904231107jf9fe544g9dcc45bda9309b5c@mail.gmail.com> From: Josh Ulrich To: doc@FreeBSD.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Subject: Possible documentation issue? X-BeenThere: freebsd-doc@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Documentation project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Apr 2009 18:39:08 -0000 Hello, The paragraph below states the default scheduler doesn't optimize for HTT but the default scheduler in the GENERIC kernel in 7.1 is now SCHED_ULE, which includes "CPU topology awareness, including for hyper-threading." (sched_ule(4)) I thought SCHED_ULE differentiates between physical and logical processors. Is that incorrect? From: http://www.freebsd.org/releases/7.1R/hardware.html "FreeBSD will take advantage of HyperThreading (HTT) support on Intel CPUs that support this feature. A kernel with the options SMP feature enabled will automatically detect the additional logical processors. The default FreeBSD scheduler treats the logical processors the same as additional physical processors; in other words, no attempt is made to optimize scheduling decisions given the shared resources between logical processors within the same CPU. Because this naive scheduling can result in suboptimal performance, under certain circumstances it may be useful to disable the logical processors with the the machdep.hlt_logical_cpus sysctl variable. It is also possible to halt any CPU in the idle loop with the machdep.hlt_cpus sysctl variable. The smp(4) manual page has more details." Best Regards, Josh -- http://quantemplation.blogspot.com http://www.fosstrading.com