Date: Fri, 20 May 2005 07:38:09 -0500 (CDT) From: Tony Shadwick <tshadwick@goinet.com> To: "Brian O'Shea" <b_oshea@yahoo.com> Cc: freebsd-questions@freebsd.org Subject: Re: Non-identical CPUs in dual-processor system Message-ID: <20050520073423.Q39659@mail.goinet.com> In-Reply-To: <20050520033802.1181.qmail@web50908.mail.yahoo.com> References: <20050520033802.1181.qmail@web50908.mail.yahoo.com>
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My general thoughts on the matter is that if the bios is happy and letting you boot up multi-cpu, then you should be fine. The OS is going to throw instructions at the two cpu's, and those instructions will be run. The only real difference between any chips that are i386-compatible that you insert in there are transistor sizes, and probably some brand-specific-deal that identifies brand name, model number, and chip-specific instructions (such as MMX). At the end of the day, you're sending x86 instructions to an x86 compatible cpu. I would think you're fine. If the OS is correctly measuring the load on the cpus, I twould think it should balance that load nicely, just be sure to compile your apps for threading where it's supported (perl comes to mind). Tony On Thu, 19 May 2005, Brian O'Shea wrote: > Hello all, > > I have a dual-processor system that I have been using with only a > single CPU for some time. Recently I got ahold of another CPU from > an old retired system. I thought that both processors were identical > (they came from what appears to be the same model PC, an HP Kayak XU). > However, after booting the system I see that the processors are not > the same: > > CPU information in mptable output: > > Processors: APIC ID Version State Family Model Step Flags > 0 0x11 BSP, usable 6 3 3 > 0x80fbff > 1 0x11 AP, usable 6 5 2 > 0x183fbff > > (sorry for the long lines) > > In this output you can see that the model for CPU0 is 3, but for > CPU 1 it is 5. Also, the flags are different. Are there likely to > be any adverse effects from using this combination of processors? > There are no errors in dmesg, and the system appears to be using > both processors: > > ... > CPU: Pentium II/Pentium II Xeon/Celeron (266.08-MHz 686-class CPU) > Origin = "GenuineIntel" Id = 0x633 Stepping = 3 > > Features=0x80fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,MMX> > > ... > MPTable: <HP XU/XW > > FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs > cpu0 (BSP): APIC ID: 0 > cpu1 (AP): APIC ID: 1 > > ... > cpu0 on motherboard > cpu1 on motherboard > > ... > SMP: AP CPU #1 Launched! > > Thanks, > -brian > > > > > Yahoo! Mail > Stay connected, organized, and protected. Take the tour: > http://tour.mail.yahoo.com/mailtour.html > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" >
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