Carsten Aulbert wrote: > Hi Kurt > > On Thursday 24 June 2010 00:53:46 Kurt Newman wrote: >> I've loaded this same i7 Nehalem machine with CentOS 5.3 >> (2.6.18-128.el5PAE), Ubuntu 9.04 (2.6.28-11-generic), and a modified >> distro with a custom kernel (2.6.32.1). >> >> The CentOS and Ubuntu kernels find all 4 cores just fine; however, my >> custom kernel only finds 1. I've enabled the following: >> >> - SMP >> - X86_BIGSMP (systems with more than 8 cpus) >> - X86_EXTENDED_PLATFORM (extended x86 platform) >> - SCHED_SMT (hyper-threading) >> - SCHED_MC (Multi-core scheduler) >> - and varied between M686 (Pentium Pro) and MCORE2 (newer Xeon) > > Just guessing, but could the CentOS and Ubuntu Kernel be a 64bit variant, > while your custom one is 32bit? (also .1 is heavily outdated .15 is the > current which apparently fixes several bugs). > > I've not been using 32bit kernel for a couple of years and never with a multi- > core system thus just poking into the dark here. Just to follow up. The solution was that I needed to enable Power Management and ACPI. Apparently newer machines require it (e.g. hyper-threading or IA64). Read http://tldp.org/HOWTO/Battery-Powered/powermgm.html#HYPERTHREAD for more information. -- To unsubscribe from this list: send the line "unsubscribe linux-admin" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
