Date: Mon, 29 Aug 2011 23:56:48 +0100 From: RW <rwmaillists@googlemail.com> To: freebsd-questions@freebsd.org Subject: Re: Turn off hyperthreading on dual core Atom? Message-ID: <20110829235648.74676b61@gumby.homeunix.com> In-Reply-To: <201108292115.PAA21491@lariat.net> References: <201108291724.LAA18734@lariat.net> <4E5BEE9C.7080706@cran.org.uk> <201108292115.PAA21491@lariat.net>
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On Mon, 29 Aug 2011 15:15:02 -0600 Brett Glass wrote: > At 01:55 PM 8/29/2011, Bruce Cran wrote: > > >Actually, the ULE scheduler does know about HyperThreading and the > >topology of such CPUs. I don't know what it does with the > >information, but it probably works to optimize cache usage etc. > > Alas, during a recent kernel build, I used the -j2 command line > option in "make" and watched as the scheduler repeatedly assigned > two instances of cc (the most CPU-intensive program) to the same core. Doesn't that make sense. If the scheduler can't put two threads from the same process on a core, it puts two processes running in the same binary. BTW I thought hyperthreading was off by default on security grounds.
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