Messages in this thread | | | Date | Tue, 10 Jan 2006 03:12:58 +0100 | From | Jesper Juhl <> | Subject | Re: Athlon 64 X2 cpuinfo oddities |
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On 10 Jan 2006 02:49:13 +0100, Andi Kleen <ak@suse.de> wrote: > Jesper Juhl <jesper.juhl@gmail.com> writes: > > > > Well, first of all you'll notice that the second core shows a > > "physical id" of 127 while the first core shows an id of 0. Shouldn't > > the second core be id 1, just like the "core id" fields are 0 & 1? > > In theory it could be an uninitialized phys_proc_id (0xff >> 1), > but it could be also the BIOS just setting the local APIC of CPU 1 > to 0xff for some reason. > > If you add a printk("PHYSCPU %d %x\n", smp_processor_id(), phys_proc_id[smp_processor_id()]) > at the end of arch/x86_64/kernel/setup.c:early_identify_cpu() what does > dmesg | grep PHYSCPU output? > Not a thing since I'm using arch/i386 here (32bit distribution (Slackware), just building a 32bit kernel optimized for K8). But, I stuck that printk into identify_cpu() in arch/i386/kernel/cpu/common.c instead, and this is what I get : $ dmesg | grep PHYSCPU [ 30.323965] PHYSCPU 0 0 [ 30.402588] PHYSCPU 1 7f
> > > > Second thing I find slightly odd is the lack of "sse3" in the "flags" list. > > I was under the impression that all AMD Athlon 64 X2 CPU's featured SSE3? > > Is it a case of: > > a) Me being wrong, not all Athlon 64 X2's feature SSE3? > > b) The CPU actually featuring SSE3 but Linux not taking advantage of it? > > c) The CPU features SSE3 and it's being utilized, but /proc/cpuinfo > > doesn't show that fact? > > d) Something else? > > It's called pni (prescott new instructions) for historical reasons. We added > the bit too early before Intel's marketing department could make up its > mind fully, so Linux is stuck with the old codename. > Does anything actually parse the /proc/cpuinfo flags field? are we really stuck with it? Ohh well, no big deal.
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