From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: unexpected IO-APIC, 2.4.36 SMP, AMD dual core Opteron Date: Thu, 07 Feb 2008 15:52:25 -0500 Message-ID: <47AB6F89.8010001@tmr.com> References: <47AA4BB4.1030702@tmr.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-smp-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: "Tuynman, William (JSC-DT/USA)[USA]" Cc: linux-smp@vger.kernel.org Tuynman, William (JSC-DT/USA)[USA] wrote: > Thanks for the response. > > For now, we are stuck with running a 2.4 kernel. We have applications > that will not run under a 2.6 kernel with a current Red Hat software > release. Yes we did try but figured it was easier and safer to run 2.4 > on the new hardware. > > We do plan to upgrade but it's going to take a year or 2 because of the > amount of code and the need to purchase new versions of COTS products, > testing and all that. In the meantime, these new machines need to run > the same applications as the other machines that we have. > > If you have the luxury of a serious test, I believe that CPU has the hardware support needed to run a 2.4 virtual machine under xen or kvm, and you might be able to postpone the upgrade of applications somewhat longer. > I tried 2.4.36 because it was just released and improvements have been > incorporated from time to time. > > Clearly worth trying. > NOTE: The kernel appears to run correctly in spite of the IO-APIC > message. So, it appears that the message is more of a warning than an > error? Possibly there is some degradation that I'm not aware of but the > system doesn't need to do a lot of IO. > > I believe you're right, but there are some boot options to control lapic, apic, io-apic, apci, etc. Some selective boot options might get rid of the warnings. I can't remember just what were 2.4, I think a lot of the ones I'm remembering ar 2.6, but there still may be some joy in trying what you can. > The IO-APIC message does not occur with a 2.6 kernel. I have one of the > machines running with 2.6.22.13 So, it appears to be 2.4 related. I > assume that's why you suggested the "live CD" > > Yes, to allow testing without any chance of messing up your existing setup. It's a safe way to find out how it's going to work. > For this build I specified the Athlon processor, which is the same as I > specified for the 2.6 kernel. I'll try the Opteron and possibly a more > generic type to see what happens. > > Let me know how you make out, bet you guys are busy right now. ;-) > Bill > > > > > -----Original Message----- > From: Bill Davidsen [mailto:davidsen@tmr.com] > Sent: Wednesday, February 06, 2008 6:07 PM > To: Tuynman, William (JSC-DT/USA)[USA] > Cc: linux-smp@vger.kernel.org > Subject: Re: unexpected IO-APIC, 2.4.36 SMP, AMD dual core Opteron > > Tuynman, William (JSC-DT/USA)[USA] wrote: > >> Hello, >> I have been getting this "An unexpected IO-APIC was found" >> > message. In checking, it occurs on 2.4.34 also. > >> The kernel was compiled for 32 bit execution and is running on >> > an AMD dual core Opteron. The machine is an HP Proliant, DL 585. > >> I'm attaching, as text, a portion of the messages file which contains >> > all of the boot information. > >> I would be happy to assist with providing additional information that >> > would be helpful to you. > >> >> > The first question I have is, why are you running a 2.4 kernel on a > modern CPU? I suspect the SMP logic in 2.4.26 is a decade older than the > hardware. SMP was pretty unusual then, multi-core was just not an end > user feature. I don't doubt that the IO-APIC may have unsupported > features. > > Might I suggest that you boot off a recent "live CD" like Fedora or > Puppy Linux, just to see if you still see a problem. If not, you will > have more information to evaluate your next step. > > > -- > Bill Davidsen > "Woe unto the statesman who makes war without a reason that will still > be valid when the war is over..." Otto von Bismark > > > - > To unsubscribe from this list: send the line "unsubscribe linux-smp" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- Bill Davidsen "Woe unto the statesman who makes war without a reason that will still be valid when the war is over..." Otto von Bismark