Date: Sun, 6 Oct 2002 11:58:16 -0700 From: Robert Clark <res03db2@verizon.net> To: Terry Lambert <tlambert2@mindspring.com> Cc: Nate Lawson <nate@root.org>, David Francheski <davidf@caymas.com>, freebsd-arch@FreeBSD.ORG, freebsd-smp@FreeBSD.ORG Subject: Re: Running independent kernel instances on dual-Xeon/E7500 system Message-ID: <20021006115816.A28963@darkstar.gte.net> In-Reply-To: <3D9EB0A4.4CD09E20@mindspring.com>; from tlambert2@mindspring.com on Sat, Oct 05, 2002 at 02:28:04AM -0700 References: <Pine.BSF.4.21.0210041721250.96201-100000@root.org> <3D9EB0A4.4CD09E20@mindspring.com>
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I've often thought it would be nice to be able to devote one processor to a RT style OS instance that continuous duty doing "throw away" work updating the display, audio, etc. Using a general purpose CPU for graphics and sound work may not result in the kinds of performance you get with a GPU, but I have to imagine it would have a better chance of encouraging "free" driver development. On the flip side, the OS instance that didn't have anything to do with audio/video could spend more of its time doing network/disk I/O, and more traditional duties. [RC] On Sat, Oct 05, 2002 at 02:28:04AM -0700, Terry Lambert wrote: > Nate Lawson wrote: > > On Fri, 4 Oct 2002, David Francheski wrote: > > > I have a dual-Xeon processor (with E7500 chipset) motherboard. > > > Can anybody tell me what the development effort would be to > > > boot and run two independent copies of the FreeBSD kernel, > > > one on each Xeon processor? By this I mean that an SMP > > > enabled kernel would not be utilized, each kernel would be UP. > > > > > > Regards, > > > David L. Francheski > > > > Not possible without another BIOS, PCI bus, and separate memory -- > > i.e. another PC. > > IPL'ing is not the same as "running". So long as you crafted the > memory image of the second OS and its page tables, etc., using the > first processor, there should be no problem running a second copy > of an OS on an AP, as a result of a START IPI from the BP, after > the code is crafted. Thus there is no need for a separate BIOS. > <snip> > -- > > I've personally considered pursuing the ability to run code seperately, > though with the same 4G address space, seperated, so as to permit > running a debugger against a "crashed" FreeBSD "system" running on an > AP, doing the debugging from the BP, as a hosted system. The cost > in labor would be 2-3 months of continuous work, I think... that is > the estimate I arrived at, when I considered the project previously. > Doing this certaily beats the cost of buying an ICE to get similar > capability. > > > It would be interesting to see what other people have to say on this, > other than "can't be done" (not to pick on you in particular, here; > this is the knee-jerk reaction many people have to things like this). > > -- Terry > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-smp" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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