Hello Bill, Well, the machine is running cleanly now. The "noapic" boot option got rid of the "IO-APIC message" with no observed ill effects. All of the CPU's come up and they all execute tasks. So, thanks for the suggestion :-) One difference that I did note from the 2.6 system was that only CPU 0 processes interrupts. But, I guess that's not a bad thing. And, what really counts is that, all of our applications run the same except faster. I noticed that the IO-APIC issue was reportedly resolved back in 2005 for the Athlon but, as you mentioned, this probably was before multi-core became available. I did try specifying Opteron as the CPU type but didn't observe any difference. In fact, the compilation appears to be the same as for the Athlon. So, no joy there. Just FYI, there were a couple of other issues that came up, mtrr and ide-scsi, that went away when I turned off the build options for them. About your suggestion: "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." That sounds interesting. If we get some time, I'll take a look at it. In the meantime, I guess I'll keep a lookout for any release notes related to SMP and IO-APIC. Take care and thanks for the suggestions, Bill P.S. Enjoyed the beer blog. -----Original Message----- From: Bill Davidsen [mailto:davidsen@xxxxxxx] Sent: Thursday, February 07, 2008 2:52 PM To: Tuynman, William (JSC-DT/USA)[USA] Cc: linux-smp@xxxxxxxxxxxxxxx Subject: Re: unexpected IO-APIC, 2.4.36 SMP, AMD dual core Opteron 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@xxxxxxx] > Sent: Wednesday, February 06, 2008 6:07 PM > To: Tuynman, William (JSC-DT/USA)[USA] > Cc: linux-smp@xxxxxxxxxxxxxxx > 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 <davidsen@xxxxxxx> > "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@xxxxxxxxxxxxxxx More majordomo > info at http://vger.kernel.org/majordomo-info.html > > -- Bill Davidsen <davidsen@xxxxxxx> "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@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
