Yes. Current AMD Athlon MP processors support SMP with the AMD 760MP chipset. There are several boards available featuring this chipset, e.g. from Tyan, ASUS, etc. Athlon/SMP is supported by recent 2.4.x kernels and also by the latest 2.2.x kernels. (David Haring)
Put it into MP1.1/1.4 compliant mode.
check "Configure Hardware" -> "View / Edit details" -> "Advanced mode" (F7 I think) for a configuration option "APIC mode" and set this to "full Table mode". This is an official Compaq recommandation. (Daniel Roesen)
(Adrian Portelli)To do this:
(Maciej W. Rozycki) Chances are that your Compaq do not make use of 82489DX APICs as they were introduced quite late -- in late 1992 or early 1993. There used to be i486 machines that implemented the APIC architecture. 82489DX is the chip that was used for them and it contained a local APIC unit and an I/O APIC unit.
From Robert Hyatt : ALR Revolution quad-6 seems quite safe, while some older revolution quad machines without P6 processors seem "iffy"...
From Alan Cox: If one of your CPU's is reporting a very low bogomips value the cache is not enabled on it. Your vendor probably provides a buggy BIOS. Get the patch to work around this or better yet send it back and buy a board from a competent supplier.
A 2.0 kernel (> 2.0.36) contains the MTRR patch which should solve this problem (select option "Handle buggy SMP BIOSes with bad MTRR setup" in the "General setup" menu).
I think buggy SMP BIOS handling is automatic in latest 2.2 kernels.
Some IBM machines have the MP1.4 bios block in the EBDA, allowed but not supported below 2.2 kernels.
There is an old 486SLC based IBM SMP box. Linux/SMP requires hardware FPU support.
Nope (according to Alan :) ), 1.4 is just a stricker specs of 1.1.
Please see the Useful Pointers for comparison between MP 1.4 and 1.1.
This is known problem with IRQ handling and long kernel locks in the 2.0 series kernels. Consider upgrading to a later 2.2 kernel.
From Jakob Oestergaard: Or, consider running xntpd. That should keep your clock right on time. (I think that I've heard that enabling RTC in the kernel also fixes the clock drift. It works for me! but I'm not sure whether that's general or I'm just being lucky)
There are some kernel fixes in the later 2.2.x series that may fix this.
The CPU number is assigned by the MB manufacturer and doesn't mean anything. Ignore it.
(Doug Ledford) Try recompiling LILO with LARGE_EBDA support and then making sure to always use make bzImage when compiling the kernel. That appears to have fixed the SMP boot hangs here on Intel multi-Xeon boards. However, please note that this also appears to break LILO in that the root= option no longer works, so make sure you rdev your kernel image at the same time you run lilo to make sure that the kernel loads the correct root filesystem at boot.
(Robert M. Hyatt) With 3 cpus, do you have a terminator in the 4th slot?
Short Answer: Change your MP setting from 1.4 to 1.1 (BIOS option), and boot with "noapic" option at boot prompt.
Long Answer: This message has nothing to do with your performance problems or why all interrupts go to one CPU. This message is for the ACPI(IO-APIC) maintainers to keep an eye on when there is new hardware. (Earle Nietzel)
To summarize the article found in official kernel documentation:
It depends.
I found that I do not need to turn off IO-APIC if I backed down from MP 1.4 and 1.1. Apparently some Xeon-based boards need to do both, but ASUS CUV4X boards do not. Turning off IO-APIC support needlessly imposes a probably small performance penalty on ASUS owners. (Vladimir G. Ivanovic)
Some IBM Netfinity machines will have problems initializing the onboard SCSI controller if MPS 1.1 is selected. Each possible LUB of each possible device on each possible bus will be queried with a timeout. Booting takes a uselessly long time. (E. Robert Bogusta)
There are reports that system with ASUS4X-DLS motherboard ran fine with IO-APIC enabled with MP 1.4.
For CUV4X-D motherboard, disabling the IDE controllers you probably can boot with MP 1.4 and APIC enabled.
(David Mentre) It has minor impact, except if you have high interrupt load (i.e., nearly nobody).
Probably you need to upgrade your BIOS version to 1010.
Xeon's chipset (440GX) and accompanying motherboard (supermicro S2DGE) I'd be using is probably (much?) more reliable and well-supported under Linux SMP than Athlons' (AMD 760/760MP) simply because they've been around longer and through many more iterations.
Xeon's larger cache (1mb on the dual 400's I'm considering) might give performance enhancement (and given that I don't have only a single scientific code I'm planning to run on this, it's probably not helpful to test benchmark specifically for my code).
Athlon's significiantly has faster clock rate (along with full-speed L2 cache in Thunderbirds, although at only 384kb) and much higher memory bandwidth with PC2100 DDR memory could help a lot.
Cost is unclear until 760MP boards and PC2100 memory are released, but it will probably be $950 to get two 1GHz 385km L2 Thunderbirds, dual motherboard and 512mb of ECC PC2100 vs $750 to get two 400MHz 1mb L2 Xeons, dual motherboard and 512mb of ECC PC100. (Daniel Freedman)
Try the later 2.2.x kernels and the knfsd patches. This is currently under investigation. (Wade Hampton)
If you are using kernels 2.2.11 or 2.2.12, get the latest kernel. For example 2.2.13 has a number of SMP fixes. Several people have reported these kernels to be unstable for SMP. These same kernels may have NFS problems that can cause lockups. Also, use a serial console to capture your oops messages. (Wade Hampton)
If the problem remains (and the other suggestions on this list didn't help either), then you could try the latest 2.3 kernels. They have more verbose (and more robust) SMP/APIC code, and automatic hard-lockup-prevention code which will produce meaningful oopses instead of a silent hang. (Ingo Molnar)
(Osamu Aoki) You MUST also disable all BIOS related power save features. Example of good configuration (Dual Celeron 466 Abit BP6):
POWER MANAGEMENT SETUP. ACPI: Disabled POWER MANAGEMENT: Disabled PM CONTROL by APM: No
(item by Wade Hampton)
A good means of debugging lockups is to get the ikd patch from Andrea Arcangeli: ftp://ftp.suse.com/pub/people/andrea/kernel-patches
There are several of debug options, but do NOT use the
soft lockup option! For newer SMP boxes,
turn kernel debugging then turn on the NMI oopser.
To verify that the NMI oopser is working, after booting the
new kernel,
/cat /proc/interrupts and verify that you are getting
NMIs. When the box locks up, you should get an OOPS.
You may also try the %eip option. This allows the kernel to print on the console the %eip address every time a kernel function is called. When the box locks up, write down the first column ordered by the second column then lookup the addresses in the System.map file. This works only in console mode.
Also note that the use of a serial console can greatly facilitate debugging kernel lockups, not just SMP kernel lockups!
A message like:
APIC error interrupt on CPU#0, should never happen. ... APIC ESR0: 00000002 ... APIC ESR1: 00000000
In this section you'll find some possible reasons for a crash of an SMP machine (credits are due to Jakob �stergaard for this part). As far as I (David) know, theses problems are Intel specific.
>From Ralf B�chle: [Related to case size and fans] It's important that the air is flowing. It of course can't where cables etc. are preventing this like in too small cases. On the other side I've seen oversized cases causing big problems. There are some tower cases on the market that actually are worse for cooling than desktops. In short, the right thing is thinking about aerodynamics in the case. Extra cases for hot peripherals are usefull as well.
Of course you can always go to Radio Shack (or similar) and get another fan. You can use the lm_sensors to monitor the CPU temperature of newer PII and PIII processors. This might help you to determine if heat is a problem. (Wade Hampton)
Don't buy cheap RAM and don't use mixed RAM modules on a motherboard that is picky about it.
Especially Tyan motherboards are known to be picky about RAM speed.
There have been some report of 10ns PC100 RAM being sold with motherboards where the CPU really needs 8ns RAM. (Wade Hampton)
Check /proc/cpuinfo to see that your CPUs are same stepping.
...and even if it is stable, DON'T overclock.
>From Ralf B�chle: Overclocking causes very subtle problems. I have a nice example, one of my overclocked old machines misscomputes a couple of pixels of a 640 x 400 fractal. The problem is only visible when comparing them using tools. So better say never, nuncas, jamais, niemals overclock.
2.0.x kernels on high performance fast ethernet systems have significant (and known) problems with a race/deadlock condition in the networking interrupt handler.
The solution is to get the latest 100BT development drivers from CESDIS Linux Ethernet device drivers site (ones that define SMPCHECK).
If you had a system using the 440FX chipset then your problem with the lockups was possibly due to a documented errata in the chipset. Here is a reference
References: Intel 440FX PCIset 82441FX (PMC) and 82442FX (DBX) Specification Update. pg. 13
http://www.intel.com/design/pcisets/specupdt/297654.htm
The problem can be fixed with a BIOS workaround (Or a kernel patch) and in fact David Wragg wrote a patch that's included with Richard Gooch's MTTR patch. For more information and a fix look here:
http://nemo.physics.ncsu.edu/~briggs/vfix.html
>From Mark Duguid, dumb rule #1 with W6LI
motherboards. ;)
Sometime, some cards are not recognized or can trigger IRQ conflicts. Try shuffling cards on slots in different ways and possibly moving them to different IRQs.
Contributed by hASCII : removing an " append="hisax=9,2,3"" line in lilo.conf allowed using a kernel from the 2.1.xx series with activated ISDN + Hisax support. Kernels from the 2.0.xx series doesn't make problems like this.
Try also to set BIOS setup option like "MP 1.4 mode" or "route PCI interrupts through IOAPIC", or "OS Type" not set to DOS neither Novell (Ingo Molnar).
If you lockup when trying to access the floppy (for example
while sound is playing) you may have to edit drivers/pci/quirks.c
and set /int isa_dma_bridge_buggy = 1;
This is a problem with my Dell WS400 dual PII/300, 2.2.x, SMP
(Wade Hampton).
Please note: Some more specific information can be found with the list of Motherboards rumored to run Linux SMP
(St�phane �colivet)
The lowest cost SMP Linux boxes with nowadays buyable processors are dual Celeron systems. Such a system is not officially possible according to Intel. Better think about the second generation of Celeron, those with 128 Kb L2 cache.
Official answer from Intel: no, Celeron cannot work in SMP mode.
Practical answer: it is possible, but requires hardware alteration for Slot 1 processors. Alteration is described by Tomohiro Kawada on his Dual Celeron System page. Of course, this kind of modification removes warranties... Some versions of Celeron processor are also available in Socket 370 format. In that case, alteration may just be done on the Socket 370 to Slot 1 adapter or may even be sold pre-wired for SMP use. (Andy Poling, Hans - Erik Skyttberg, James Beard)
There is also a motherboard (ABIT BP6) allowing two Celerons in Socket 370 format to be inserted (Martijn Kruithof, Ryan McCue). ABIT Computer BP6 verified tested and native to linux with dual ppga socket 370 (Andre Hedrick).
Fine, thank you.
It may work. However, overclocking this kind of system is not as easy as overclocking a mono-processor one. It is definitly not a good idea for a production system. For personal use, dual Celeron 300A systems running rock-solid at 450 MHz have been reported. (numerous people)
It is impossible. Celeron processors have nearly the same features as basic Pentium II chips. If you want more than 2 processors in your system, you'll have to look at Pentium Pro, Pentium II Xeon or Pentium III (?) boxes.
A system using a "re-enable" Celeron processor and a Pentium II processor with the same steppings may theorically work.
Alexandre Charbey as made such a system: