Date: Tue, 04 Feb 2003 12:32:06 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Julian Elischer <julian@elischer.org> Cc: John Baldwin <jhb@FreeBSD.org>, freebsd-smp@freebsd.org, Chris Luke <chrisy@flix.net>, Brendon and Wendy <brendy33@attbi.com> Subject: Re: mp_machdep.c patch Message-ID: <3E402346.F90982F3@mindspring.com> References: <Pine.BSF.4.21.0302041135190.84482-100000@InterJet.elischer.org>
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Julian Elischer wrote: > > Correct, BIOS settings have no effect on whether or not > > FreeBSD "sees" HTT CPUs. > > Can we have a way of 'nobbling' certain cpus? > e.g. don't use "#1 and #3?" The limit is 32. A bitmap and a lookup table of entries to bits is enough for now, probably. We all talked about this approach before, when we were talking about a simple negaffinity feature in the scheduler, so that new threads ran on different CPUs from exisitng threads; the same principle should work for picking CPUs to start/not start, and it would be easy to set the integer value as a tunable (i.e. in the boot loader). The other alternative is to allow control of whether or not the CPUID patch probe happens or not (see other posting). It's probably a longer term solution; if you need something fast, don't wait for it, unless you want to hack it yourself. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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