Date: Mon, 13 Mar 2006 15:23:03 +0000 From: petefrench@ticketswitch.com To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/94410: Cannot disable hyperthreading if more than one phsyical processor exists Message-ID: <E1FIosx-000P66-JI@websvr01.rattatosk> Resent-Message-ID: <200603131530.k2DFUGQb078279@freefall.freebsd.org>
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>Number: 94410 >Category: kern >Synopsis: Cannot disable hyperthreading if more than one phsyical processor exists >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Mon Mar 13 15:30:16 GMT 2006 >Closed-Date: >Last-Modified: >Originator: Web Administrator >Release: FreeBSD 6.0-RELEASE i386 >Organization: Ticket Switch Ltd >Environment: System: FreeBSD websvr01.rattatosk 6.0-RELEASE FreeBSD 6.0-RELEASE #0: Wed Dec 28 21:55:17 GMT 2005 webadmin@turpentine.rattatosk:/usr/obj/usr/src/sys/RATTATOSK-SMP i386 HP blade running 6.0-RELEASE >Description: If an SMP kernel is run on a machine with more than one physical processor there seems to be no way to disable hyperthreading. The usual flags appear to set the masks correctly, but I am still seeing processes scheduled on 4 CPUs in 'top'. This machine only has two physical CPUs. In a machine with only one physical CPU then the behaviour works as expected. >How-To-Repeat: Boot up 6.0 on a machine with more than one hyperthreading capabale processors installed, but with the flags turned off and observer that processes are still scheduled on all the hyperthreading processors. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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