at this point, i'm trying to rationalize why i'm seeing this in the output of dmesg: [ 0.000000] smpboot: Allowing 16 CPUs, 8 hotplug CPUs on my quad-core asus laptop, as in -- where is that "16" coming from? if i list /proc/cpuinfo, i see 8 processors, so i'm just trying to understand what "16" represents, so let's read backwards. first, that line above seems to be printed from arch/x86/kernel/smpboot.c: pr_info("Allowing %d CPUs, %d hotplug CPUs\n", possible, max_t(int, possible - num_processors, 0)); so, *apparently*, by that time, the boot process has established that there are 16 "possible" processors, but only 8 actual ones. but who decided there were 16 "possible" processors? just above that in the same file, we have: if (setup_possible_cpus == -1) { possible = num_processors; #ifdef CONFIG_HOTPLUG_CPU if (setup_max_cpus) possible += disabled_cpus; #else if (possible > i) possible = i; #endif } else possible = setup_possible_cpus; total_cpus = max_t(int, possible, num_processors + disabled_cpus); whoa, so it appears that we get "possible" cpus from adding the number of *actual* cpus to the number of "disabled" cpus. but what is a "disabled" cpu, and who decides how many there are? last thing i notice is this earlier in my dmesg output: [ 0.000000] ACPI: PM-Timer IO Port: 0x408 [ 0.000000] ACPI: Local APIC address 0xfee00000 [ 0.000000] ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x02] lapic_id[0x02] enabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x03] lapic_id[0x04] enabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x04] lapic_id[0x06] enabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x05] lapic_id[0x01] enabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x06] lapic_id[0x03] enabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x07] lapic_id[0x05] enabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x08] lapic_id[0x07] enabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x09] lapic_id[0x08] disabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x0a] lapic_id[0x09] disabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x0b] lapic_id[0x0a] disabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x0c] lapic_id[0x0b] disabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x0d] lapic_id[0x0c] disabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x0e] lapic_id[0x0d] disabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x0f] lapic_id[0x0e] disabled) [ 0.000000] ACPI: LAPIC (acpi_id[0x10] lapic_id[0x0f] disabled) which certainly seems to be related to all of this -- 8 enabled and 8 disabled. so i'm going to keep following this back, unless someone wants to break it to me what is going on. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================