Re: Also seeing 2 x quad-core system slower that 2 x dual core

Yes, if the claim is that the hardware is absolutely identical apart
from one having two quad-core CPUs instead of two dual-core, the next
step is to disable half of the CPUs and confirm that the problem goes away.

Just comming back to this today, will do a side by side compare of the dmesg
later to make sure that they *are* identical as claimed, but the idea of
disabling half the CPU's is an excellent one!

Aha, brilliant idea!

Check dmesg for the APIC numbers corresponding to the CPUs you want to
disable and add the corresponding entries to /boot/loader.conf, e.g.:

You mean this bit?

FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs
cpu0 (BSP): APIC ID: 0
cpu1 (AP): APIC ID: 1
cpu2 (AP): APIC ID: 2
cpu3 (AP): APIC ID: 3
cpu4 (AP): APIC ID: 4
cpu5 (AP): APIC ID: 5
cpu6 (AP): APIC ID: 6
cpu7 (AP): APIC ID: 7

hint.lapic.1.disable="1"
hint.lapic.3.disable="1"
hint.lapic.5.disable="1"
hint.lapic.7.disable="1"

gives me...

hint.lapic.1.disable="1"
hint.lapic.3.disable="3"
hint.lapic.5.disable="5"
hint.lapic.7.disable="7"

rebooting now to give it a try...

-pete.
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Relevant Pages

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