Date: Sun, 4 Apr 2010 20:06:07 GMT From: Garrett Cooper <gcooper@FreeBSD.org> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/145385: Logical processor cannot be disabled for some SMT-enabled Intel procs Message-ID: <201004042006.o34K67Uh063347@www.freebsd.org> Resent-Message-ID: <201004042010.o34KA9TI018510@freefall.freebsd.org>
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>Number: 145385 >Category: kern >Synopsis: Logical processor cannot be disabled for some SMT-enabled Intel procs >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sun Apr 04 20:10:08 UTC 2010 >Closed-Date: >Last-Modified: >Originator: Garrett Cooper >Release: 9-CURRENT >Organization: Cisco Systems, Inc. >Environment: FreeBSD bayonetta.local 9.0-CURRENT FreeBSD 9.0-CURRENT #0 r205872M: Sat Apr 3 18:14:55 PDT 2010 root@bayonetta.local:/usr/obj/usr/src/sys/BAYONETTA amd64 >Description: As discussed here: http://forums.freebsd.org/showthread.php?t=12527 and here: http://www.mail-archive.com/freebsd-hackers@freebsd.org/msg70605.html logical CPUs cannot be disabled via machdep.hlt_logical_cpus tunable because it's incorrectly detecting that the SMT-enabled processor doesn't have hyperthreading cores (it's a Xeon X-series equivalent workstation processor, which has hyperthreading technology enabled). >How-To-Repeat: Boot with an X-series Xeon or Hyperthreading enabled Pentium processor chip and set `machdep.hlt_logical_cpus' to 1. The logical processors will not be disabled. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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