Date: Thu, 30 May 1996 18:01:28 +0000 From: Poul-Henning Kamp <phk@critter.tfs.com> To: erich@uruk.org Cc: freebsd-smp@freebsd.org Subject: Re: How do you get the SMP code Message-ID: <511.833479288@critter.tfs.com> In-Reply-To: Your message of "Thu, 30 May 1996 10:27:10 MST." <199605301727.KAA07610@uruk.org>
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> I'm also about to make a public release of the new bootloader I've been > working on. That has consumed a lot of time as well. You may want to send an email to wpaul@freebsd.org who has lately taken to look at bootstrap stuff. > I had re-written the probe and startup code for Linux-SMP, and am willing > to do so for FreeBSD (given that I don't mortally insult anyone :-). for doing work for us ?? You must be kidding... > Do you guys have any particular preference for how it's done in > FreeBSD ? no not really. > It turns out that the whole "NCPU" thing in Linux was (and is, as I > have to submit patches because people are constantly breaking it) > a pain in the ass. > > At the very least, it should be changed to "MAXCPU", with dynamic > activation of CPUs up to the maximum (this is what Linux does, though > they still call it NCPU). That's how our NCPU is intended. We hope to keep the size to < 64bytes per cpu if we can... > Ideally (this is what I'm going to do for Utah's Mach4 distribution), > it should just be "options SMP" and dynamically allocate CPU structures > as necessary... and if it doesn't find other an MPS configuration, it > will still function without getting confused by the possible lack of > a local APIC on the CPU. Yes, that would be nice, but until I have some numbers that tell me what the extra indirection means, I'm kind of reluctant to do so. Nasty question time: Can part of the local apic registers be used as "per-cpu registers" without too much performance penalty ? I would really love to have one or two 32bit registers local per CPU to speed up all this stuff... -- Poul-Henning Kamp | phk@FreeBSD.ORG FreeBSD Core-team. http://www.freebsd.org/~phk | phk@login.dknet.dk Private mailbox. whois: [PHK] | phk@ref.tfs.com TRW Financial Systems, Inc. Future will arrive by its own means, progress not so.
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