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User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Firefox/17.0 Build Identifier: With 3.6.7-5.fc18.x86_64, the kernel is only starting 2 of 4 cores: $ egrep 'processor|model name' /proc/cpuinfo processor : 0 model name : AMD Phenom(tm) II X4 945 Processor processor : 1 model name : AMD Phenom(tm) II X4 945 Processor In the past, the kernel was correctly starting all 4 cores. I'll attach acpidump output. This kernel boot log message might or might not be relevant: Nov 25 07:53:48 i kernel: setup_percpu: NR_CPUS:128 nr_cpumask_bits:128 nr_cpu_ids:4 nr_node_ids:1 Reproducible: Always Steps to Reproduce: 1. Boot fedora 18. 2. cat /proc/cpuinfo Actual Results: 2 cores are running Expected Results: 4 cores should be running
Created attachment 651220 [details] Output of acpidump Output of acpidump
can you attach the output of dmesg please.
Created attachment 653203 [details] dmesg output First 1k lines of dmesg output (I'm assuming post-boot messages are irrelevant & have trimmed the file. Let me know if my assumption is wrong).
Hi, Ralph, Could you also attach: 1. The full output of: $ cat /proc/cpuinfo 2. And as root, the output of: $ lspci -s 0:18.* -xxxx please ? Thanks!
Oh, and I also forgot to ask .. Could you go through your BIOS options and make sure that there aren't any obvious things like "downcore" or "disable core" that is set? Just in case. Thanks!
Created attachment 653296 [details] lspci.txt Output of lspci -s 0:18.* -xxxx
Created attachment 653309 [details] /proc/cpuinfo
Rebooted yet again to look through BIOS options. Did not find any relevant. Rebooted in Linux. All 4 cores back. WTF! Your guess is probably better than mine. Unless the information attached above contains a smoking gun, feel free to close as 'cannot reproduce'... if it reoccurs, I'll reopen...
Weird.. Yes, in one of the CPU PCI configuration registers: > 00:18.3 Host bridge: Advanced Micro Devices [AMD] Family 10h Processor Miscellaneous Control ... > 190: 0c 00 00 00 00 00 00 00 00 04 78 00 00 00 00 00 ^^ Bit 2 and 3 are set, which disables core 2 and 3. This is (was?) set by the BIOS. If you see all 4 cores now, run the lspci command again, and see if those bits are clear now .. you should see 00. Not really sure why it was set and now it's clear, and why your BIOS decided to change it's mind after reboot. Thanks! -Jacob
Ok, the evidence is that this is nothing to do with fedora and everything to do with some buggy lump of closed source bios. Closing.