Date: Sat, 23 Nov 2013 11:46:14 +0000 (UTC) From: Alexander Motin <mav@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r258495 - head/release/doc/en_US.ISO8859-1/hardware Message-ID: <201311231146.rANBkEjr075367@svn.freebsd.org>
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Author: mav Date: Sat Nov 23 11:46:13 2013 New Revision: 258495 URL: http://svnweb.freebsd.org/changeset/base/258495 Log: MFreleng/8.4 r251256 (by hrs): Update description of logical CPU handling in the latest releases and remove obsolete sysctl variable machdep.hlt_logical_cpus. MFC after: 3 days Modified: head/release/doc/en_US.ISO8859-1/hardware/article.xml Modified: head/release/doc/en_US.ISO8859-1/hardware/article.xml ============================================================================== --- head/release/doc/en_US.ISO8859-1/hardware/article.xml Sat Nov 23 03:56:03 2013 (r258494) +++ head/release/doc/en_US.ISO8859-1/hardware/article.xml Sat Nov 23 11:46:13 2013 (r258495) @@ -177,16 +177,13 @@ bugs may generate some problems. Perusal of the archives of the &a.smp; may yield some clues.</para> - <para>&os; will take advantage of HyperThreading (HTT) support - on &intel; CPUs that support this feature. The - default &os; 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 - <varname>machdep.hyperthreading_allowed</varname> tunable. + <para>&os; will take advantage of SMT (Symmetric MultiThreading, + also known as HyperThreading on &intel; CPUs) on the supported + CPUs. The <filename>GENERIC</filename> kernel which is + installed by default will automatically detect the additional + logical processors. The default &os; scheduler recognizes + processor topology on the system and selects logical and + physical processors to obtain optimal performance. The &man.smp.4; manual page has more details.</para> <para>&os; will take advantage of Physical Address Extensions
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