On Mon, Feb 25, 2008 at 02:05:45PM -0800, Yinghai Lu wrote: >On Mon, Feb 25, 2008 at 11:08 AM, Ravikiran Thirumalai ><[EMAIL PROTECTED]> wrote: >> ... >> Andi, Yes. AMD based vSMPowered systems uses clustered APICs, and this >> check base on cpu vendor id is not good :(. > >please check if you happy with > >http://lkml.org/lkml/2008/2/24/273 >
I don't quite understand the purpose of the patch to begin with. Looking at the current x86 git tree, apic_is_clustered_box is used only to determine if tsc is synchronized on the platform. The AMD docs imply that TSC's are not guaranteed to be synced across cores between nodes -- Opteron BKDG for family 10h, Section 2.9.4: <quote> Note: Timers associated with different CPU cores in the same processor increment at the same rate. Timers associated with different CPU cores in different processors increment at slightly different rates if (1) they are located on different nodes and (2) CLKIN for these nodes is derived from different, non-synchronized oscillator sources. </quote> But that is not what the x86 tree does (with your patches) -- it looks for the X86_FEATURE_CONSTANT_TSC at unsynchronized_tsc() and assumes a synchronized clock. Huh!?? Am i missing something here? X86_FEATURE_CONSTANT_TSC is set from CPUID Fn8000_0007 -- TscInvariant bit, which implies TSC is not affected by change in PM states. This does not talk about whether CLKIN for different packages are from synchronized/non synchronized oscillator sources in the above quote. Thanks, Kiran -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/