2.6.32.1 kernel unable to use more than 2 of 16 CPUs on Intel E5540 (i7)
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From: Kurt Newman on 24 Jun 2010 18:00 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I'm posting here to get a bit of help to figure out this issue, or find advice on a better mailing list or location to post this question. The linux-smp and linux-config lists don't get many posts, while linux-admin hasn't yielded much (perceived) help. - ------------------------ My problem and question is: I've tried 2.6.31.13 and 2.6.32.1, but none of these compilations find all 16 CPUs on this E5540 (2 cpus, 4 cores each, 2 HT threads each). However, using these same custom kernels on an Intel 5130, shows all 4 "cpus" (2 cpus, 2 cores each, no HT). I've also tried older kernels from common distros that find all 16 cpus just fine. I'm guessing they patched in support for additional hardware. Q: What am I doing wrong, that prevents this kernel from seeing all CPUs? Or, could someone point me in the right direction? - ------------------------ Relevant background information: 1) I am limited to a 32-bit OS and an older kernel because of some software limitations. 2) While I've enabled CONFIG_HOTPLUG_CPU, I've confirmed that I'm not passing any kernel args that would limit what is used (e.g. maxcpus=). 3) From the things I've looked at (e.g. /sys), the kernel seems to know that there's 16 CPUs, but will only use 2. 4) I'm attaching my kernel config, dmesg output, /sys output, and /proc/cpuinfo output to help. NOTE: I've tried using CONFIG_MCORE2 and CONFIG_M686, neither of these changes anything. Thank you for your time, Kurt -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkwj0eQACgkQ0rcig5YkL7E3vgCghDRO1VXMh9kap1yUhBoOSw7I UV8An35Zqt7cf3v5vJqKrh43lbYXyqVv =VLnf -----END PGP SIGNATURE----- |