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    SubjectRe: [PATCH 1/3] mce: Add a msg string to the MCE tracepoint
    Em 29-02-2012 14:20, Luck, Tony escreveu:
    >> IMHO, before removing those fields, it would be better to first implement
    >> what is there at the mcelog userspace parser for the Intel machines into
    >> kernelspace (or to look into its source code), and check what registers
    >> aren't used by either AMD 64 MCE decoder or by the Intel MCE decoder.
    >>
    >> Tony,
    >>
    >> Is there anyone at Intel working on porting it to kernelspace?
    >
    > The mcelog code just looks at model specific fields in MCi_STATUS
    > and MCi_MISC. We could move it to the kernel - but I don't see
    > much value in doing so.

    I see a few reasons:

    - it would be consistent with what's being done at AMD. So, all x86
    arch will report errors at the same way;

    - userspace won't need to run an extra daemon/tool to decode the
    errors;

    - fatal errors won't be lost (well, in fact, you have there already
    a parser for fatal errors. Not sure if all possible fatal errors
    are covered here, nor what else is needed, as you have already
    there part of mcelog decoder);

    - a single place to maintain, when new cpu families are added;

    - it makes easier to centralize the hardware error information,
    as there's no need to enrich the error on userspace.

    > In this case all the information we need
    > is carried in status/misc - so as long as we keep all of those
    > bits (and the cpu family/model) we can safely decode/analyze later.

    Hmm... the mcelog tool opens the /proc/cpuinfo:

    $ grep cpuinfo *
    mcelog.c: f = fopen("/proc/cpuinfo","r");
    mcelog.c: Eprintf("warning: Cannot parse /proc/cpuinfo\n");
    mcelog.c: Eprintf("warning: Cannot open /proc/cpuinfo\n");
    tsc.c: asprintf(&fn, "/sys/devices/system/cpu/cpu%d/cpufreq/cpuinfo_max_freq", cpu);
    tsc.c: /* /sys exists, but no cpufreq -- use value from cpuinfo */

    That probably means that the needed cpu family/model info is not (or may not) be
    stored at the MCE structure.

    >
    > -Tony



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