Date: Fri, 30 Nov 2007 11:33:51 +0000 From: Pete French <petefrench@ticketswitch.com> To: kometen@gmail.com, kris@FreeBSD.org Cc: max@love2party.net, freebsd-stable@freebsd.org Subject: Re: Also seeing 2 x quad-core system slower that 2 x dual core Message-ID: <E1Iy47z-0001f0-QX@dilbert.ticketswitch.com> In-Reply-To: <474FD17D.7080209@FreeBSD.org>
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> 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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