Ok... figured it out. Short answer: Rookie mistake. Longer answer: the old-style Compaq BIOS was set for Operating System = Other rather than for UNIX/Linux. So APIC and SMP were disabled. In case if helps anyone, below is the working 4 processor SMP output from xm dmesg. The system ain't fast, but it was free (and its not clogging a landfill somewhere). Thanks, Bryan ________________________________________________________________ __ __ _____ _ ____ _ ___ _ _ _____ _ _ ____ \ \/ /___ _ __ |___ / / | |___ \ / |/ _ \| || | |___ / / | ___| | ___| \ // _ \ _ \ |_ \ | | __) |__| | (_) | || |_ |_ \ | | / _ \ |___ \ / \ __/ | | | ___) || |_ / __/|__| |\__, |__ _| ___) || || __/ |___) | /_/\_\___|_| |_| |____(_)_(_)_____| |_| /_/ |_|(_)____(_)_(_)___|_|____/ http://www.cl.cam.ac.uk/netos/xen University of Cambridge Computer Laboratory Xen version 3.1.2-194.3.1.el5 (mockbuild at centos.org) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-48)) Thu May 13 13:02:01 EDT 2010 Latest ChangeSet: unavailable (XEN) Command line: dom0_mem=1024M crashkernel=128M at 16M (XEN) Video information: (XEN) VGA is text mode 80x25, font 8x16 (XEN) VBE/DDC methods: V2; EDID transfer time: 2 seconds (XEN) Disc information: (XEN) Found 2 MBR signatures (XEN) Found 2 EDD information structures (XEN) Xen-e820 RAM map: (XEN) 0000000000000000 - 000000000009d800 (usable) (XEN) 000000000009d800 - 00000000000a0000 (reserved) (XEN) 00000000000f0000 - 0000000000100000 (reserved) (XEN) 0000000000100000 - 00000000efffc000 (usable) (XEN) 00000000efffc000 - 00000000f0000000 (ACPI data) (XEN) 00000000fec00000 - 00000000fec10000 (reserved) (XEN) 00000000fee00000 - 00000000fee10000 (reserved) (XEN) 00000000fff80000 - 0000000100000000 (reserved) (XEN) 0000000100000000 - 00000002c0000000 (usable) (XEN) Kdump: 128MB (131072kB) at 0x1000000 (XEN) System RAM: 11007MB (11271780kB) (XEN) Xen heap: 9MB (9740kB) (XEN) Domain heap initialised: DMA width 32 bits (XEN) PAE enabled, limit: 16 GB (XEN) Processor #0 6:10 APIC version 17 (XEN) Processor #1 6:10 APIC version 17 (XEN) Processor #2 6:10 APIC version 17 (XEN) Processor #3 6:10 APIC version 17 (XEN) IOAPIC[0]: apic_id 8, version 17, address 0xfec00000, GSI 0-34 (XEN) Enabling APIC mode: Flat. Using 1 I/O APICs (XEN) Using scheduler: SMP Credit Scheduler (credit) (XEN) Detected 701.650 MHz processor. (XEN) I/O virtualisation disabled (XEN) CPU0: Intel Pentium III (Cascades) stepping 04 (XEN) Booting processor 1/0 eip 90000 (XEN) CPU1: Intel Pentium III (Cascades) stepping 04 (XEN) Booting processor 2/1 eip 90000 (XEN) CPU2: Intel Pentium III (Cascades) stepping 04 (XEN) Booting processor 3/2 eip 90000 (XEN) CPU3: Intel Pentium III (Cascades) stepping 04 (XEN) Total of 4 processors activated. (XEN) ENABLING IO-APIC IRQs (XEN) -> Using new ACK method (XEN) ..MP-BIOS bug: 8254 timer not connected to IO-APIC (XEN) Platform timer overflows in 2 jiffies. (XEN) Platform timer is 1.193MHz PIT (XEN) Brought up 4 CPUs (XEN) *** LOADING DOMAIN 0 *** (XEN) elf_parse_binary: phdr: paddr=0xc0400000 memsz=0x28771c (XEN) elf_parse_binary: phdr: paddr=0xc0688000 memsz=0x164000 (XEN) elf_parse_binary: memory: 0xc0400000 -> 0xc07ec000 (XEN) elf_xen_parse_note: GUEST_OS = "linux" (XEN) elf_xen_parse_note: GUEST_VERSION = "2.6" (XEN) elf_xen_parse_note: XEN_VERSION = "xen-3.0" (XEN) elf_xen_parse_note: VIRT_BASE = 0xc0000000 (XEN) elf_xen_parse_note: PADDR_OFFSET = 0xc0000000 (XEN) elf_xen_parse_note: ENTRY = 0xc0400000 (XEN) elf_xen_parse_note: HYPERCALL_PAGE = 0xc0401000 (XEN) elf_xen_parse_note: FEATURES = "writable_page_tables|writable_descriptor_tables|auto_translated_physmap|pae_pgdir_above_4gb|supervisor_mode_kernel" (XEN) elf_xen_parse_note: PAE_MODE = "yes" (XEN) elf_xen_parse_note: LOADER = "generic" (XEN) elf_xen_addr_calc_check: addresses: (XEN) virt_base = 0xc0000000 (XEN) elf_paddr_offset = 0xc0000000 (XEN) virt_offset = 0x0 (XEN) virt_kstart = 0xc0400000 (XEN) virt_kend = 0xc07ec000 (XEN) virt_entry = 0xc0400000 (XEN) Xen kernel: 32-bit, PAE, lsb (XEN) Dom0 kernel: 32-bit, PAE, lsb, paddr 0xc0400000 -> 0xc07ec000 (XEN) PHYSICAL MEMORY ARRANGEMENT: (XEN) Dom0 alloc.: 000000003c000000->000000003e000000 (253952 pages to be allocated) (XEN) VIRTUAL MEMORY ARRANGEMENT: (XEN) Loaded kernel: c0400000->c07ec000 (XEN) Init. ramdisk: c07ec000->c0efec00 (XEN) Phys-Mach map: c0eff000->c0fff000 (XEN) Start info: c0fff000->c0fff46c (XEN) Page tables: c1000000->c100f000 (XEN) Boot stack: c100f000->c1010000 (XEN) TOTAL: c0000000->c1400000 (XEN) ENTRY ADDRESS: c0400000 (XEN) Dom0 has maximum 4 VCPUs (XEN) elf_load_binary: phdr 0 at 0xc0400000 -> 0xc068771c (XEN) elf_load_binary: phdr 1 at 0xc0688000 -> 0xc0733cc4 (XEN) Initrd len 0x712c00, start at 0xc07ec000 (XEN) Scrubbing Free RAM: ..................................................................................................done. (XEN) Xen trace buffers: disabled (XEN) Std. Loglevel: Errors and warnings (XEN) Guest Loglevel: Nothing (Rate-limited: Errors and warnings) (XEN) Xen is relinquishing VGA console. (XEN) *** Serial input -> DOM0 (type \047CTRL-a\047 three times to switch input to Xen). (XEN) Freed 108kB init memory. (XEN) ioapic_guest_write: apic=0, pin=2, old_irq=-1, new_irq=0 (XEN) ioapic_guest_write: old_entry=00010000, new_entry=000009f0 (XEN) ioapic_guest_write: Attempt to add IO-APIC pin for in-use IRQ! > > Not looking to run Windows guests... so no problem there. And a free > server beats $60 any day :-) > > By the way, I have another one that is just about the same (4 x P-III > 900Mhz and 16GB) running ESXi 3.5 U5 like a champ with no problems, so I > was hoping to get Xen up on this one (for a project I need to test out Xen > with). > > And no, I have not explored KVM on there yet... even though I did load it. > I'm really just interested in Xen right now. > > B. > >> Well, I can't say for sure the reason why it doesn't see all cpus, but I >> do >> know a P-III system is not going to support virtualization technology, >> so >> you would never be able to run windows guests on it. Only systems sold >> in >> the last year or two support VT. And motherboards that do support it are >> fairly cheap - starting in the $60 range. >> >> Anywho, have you tried KVM instead? >> >> >> >> -----Original Message----- >> From: centos-virt-bounces at centos.org >> [mailto:centos-virt-bounces at centos.org] >> On Behalf Of Bryan A. Ignatow >> Sent: Thursday, June 03, 2010 10:27 AM >> To: Discussion about the virtualization on CentOS >> Subject: [CentOS-virt] Xen 3.1.2 on CentOS 5.5 doesn't see all 4 CPUs >> >> Hello all, >> >> I've been digging around on this for a few days and I have not come up >> with >> a solution. >> >> I have a Compaq ProLiant DL580 (G1, the old tan Compaq) with 4 x 700MHz >> P-III CPUs and 11GB of memory. I've loaded CentOS 5.5 with >> Virtualization >> (Xen) + KVM and patched up to current (full KS packages file list at the >> end). >> >> When it boots, Xen only detects a single CPU as shown in the xm dmesg >> output >> (full output and the end): >> >> (XEN) Detected 701.650 MHz processor. >> (XEN) I/O virtualisation disabled >> (XEN) CPU0: Intel Pentium III (Cascades) stepping 04 >> (XEN) Platform timer overflows in 2 jiffies. >> (XEN) Platform timer is 1.193MHz PIT >> (XEN) Brought up 1 CPUs >> [...] >> (XEN) Dom0 has maximum 1 VCPUs >> >> >> The system shows all 4 CPUs when booted outside of Xen. >> >> Any ideas on Xen options or anything I can try to see if I can get all 4 >> CPUs? >> >> >> Thanks, >> >> Bryan >> >> _______________________________________________ >> CentOS-virt mailing list >> CentOS-virt at centos.org >> http://lists.centos.org/mailman/listinfo/centos-virt >> > > > -- > Bryan A. Ignatow > bryan at ignatow.org > > _______________________________________________ > CentOS-virt mailing list > CentOS-virt at centos.org > http://lists.centos.org/mailman/listinfo/centos-virt > -- Bryan A. Ignatow bryan at ignatow.org