Date: Sun, 2 Jun 2013 15:47:22 +0000 (UTC) From: Hiroki Sato <hrs@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-releng@freebsd.org Subject: svn commit: r251256 - releng/8.4/release/doc/en_US.ISO8859-1/hardware Message-ID: <201306021547.r52FlM4k031766@svn.freebsd.org>
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Author: hrs Date: Sun Jun 2 15:47:22 2013 New Revision: 251256 URL: http://svnweb.freebsd.org/changeset/base/251256 Log: Update description of logical CPU handling in the latest releases and remove obsolete sysctl variable machdep.hlt_logical_cpus. Pointed out by: mav Approved by: re (implicitly) Modified: releng/8.4/release/doc/en_US.ISO8859-1/hardware/article.xml Modified: releng/8.4/release/doc/en_US.ISO8859-1/hardware/article.xml ============================================================================== --- releng/8.4/release/doc/en_US.ISO8859-1/hardware/article.xml Sun Jun 2 15:36:29 2013 (r251255) +++ releng/8.4/release/doc/en_US.ISO8859-1/hardware/article.xml Sun Jun 2 15:47:22 2013 (r251256) @@ -167,20 +167,13 @@ 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. A kernel with the - <literal>options SMP</literal> feature enabled will - automatically detect the additional logical processors. 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.hlt_logical_cpus</varname> sysctl variable. - It is also possible to halt any CPU in the idle loop with the - <varname>machdep.hlt_cpus</varname> sysctl variable. The + <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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