Core 2 Errata -- problematic or overblown?

By: rwessel (robertwessel.delete@this.yahoo.com), June 29, 2007 3:20 am
Room: Moderated Discussions
Matt Sayler (sayler@thewalrus.org) on 6/27/07 wrote:
---------------------------
>http://marc.info/?l=openbsd-misc&m=118296441702631
>
> (...)
>
>How significant were the TLB handling changes?
>
>In general, do Core2 chips seem to be more or less buggy than previous iterations?
>Are errata par for the course as we approach billion-transistor commodity MPUs?


Just for a little historical perspective, here are a few select items from the "Model Dependent Information" section of my old "IBM 4341 Processor - Model Group 2 - Functional Characteristics and Processor Complex Configurator" manual. From 1981.

And in case you don't know, a 4341 is a modest sized S/370 mainframe from that era.

I typed the following from the source, so there may well be transcription errors. Some of these are outright bugs, and some skate the boundary between defined and undefined behavior, but all are unexpected given the architectural definition. OTOH, all of them are, in a practical sense, minor. Anyway:


Condition Code Setting
The nullification of NC, CLC, OC, XC, TRT an ZAP instructions does not cause the instruction to be executed as if it were specified as a no operation. The condition code may be altered by any of these six instructions even though the instruction has been nullified. (rw: nullified instructions are not supposed to leave any traces)


Segment Table Entry
The 4341 does not check bits 4-7, 29 and 30 of the segment table entry for zeros.


Reference and Change Recording
The recording of reference and change bits is accurate with the following exceptions:

- The reference bit may be set because of storage operand fetching of a nullified or suppressed instruction.

- The reference bit may be set because of prefetching of an instruction...

- The reference bit may be set because of channel prefetching of CCW, IDAW or data during an output operation.

- The reference bit will not be set, if following a RRB or SSK instruction, which sets the reference bit to zero, all subsequent accesses to the storage block find the data in the high speed buffer. (rw: IOW, the reference bit won't get set if all reads from that page subsequent to clearing the bit hit cache).

- Change bits may be set for the operands of a unit of operation that is nullified because of a page translation exception. For example the destination operand of a Move instruction may cross a page boundary and encounter a page translation exception at the boundary. In this case the instruction is nullified so that the portion of the operand up to the boundary is restored to its original value, but the change bit may remain set after the nullification of the instruction.
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TopicPosted ByDate
Core 2 Errata -- problematic or overblown?Matt Sayler2007/06/27 11:39 AM
  Core 2 Errata -- problematic or overblown?anonymous2007/06/27 02:08 PM
  Core 2 Errata -- problematic or overblown?David Kanter2007/06/27 02:34 PM
    Core 2 Errata -- problematic or overblown?Joe Chang2007/06/27 03:01 PM
    Core 2 Errata -- problematic or overblown?A.T. Ho2007/06/27 04:33 PM
      Core 2 Errata -- problematic or overblown?David Kanter2007/06/27 06:31 PM
      Core 2 Errata -- problematic or overblown?Andi Kleen2007/06/28 12:35 AM
        Core 2 Errata -- problematic or overblown?anonymous2007/06/28 04:16 AM
    Core 2 Errata -- problematic or overblown?Jack A.2007/06/29 07:43 PM
      Core 2 Errata -- problematic or overblown?anon2007/07/01 10:13 AM
        AMD DocumentationDavid Kanter2007/07/01 11:03 AM
  Core 2 Errata -- problematic or overblown?Andi Kleen2007/06/27 04:02 PM
    Core 2 Errata -- problematic or overblown?Paul2007/06/27 05:06 PM
    Core 2 Errata -- problematic or overblown?Groo2007/06/28 01:10 AM
  Core 2 Errata -- problematic or overblown?Linus Torvalds2007/06/27 05:10 PM
    Core 2 Errata -- problematic or overblown?Rob Thorpe2007/06/28 01:11 AM
      Core 2 Errata -- problematic or overblown?JS2007/06/28 04:32 AM
        Core 2 Errata -- problematic or overblown?Rob Thorpe2007/06/28 05:15 AM
          Core 2 Errata -- problematic or overblown?JS2007/06/28 09:55 PM
            Core 2 Errata -- problematic or overblown?Rob Thorpe2007/06/29 12:44 AM
      Core 2 Errata -- problematic or overblown?Linus Torvalds2007/06/28 08:30 AM
        Core 2 Errata -- problematic or overblown?philt2007/06/28 04:28 PM
          Core 2 Errata -- problematic or overblown?Linus Torvalds2007/06/28 07:31 PM
            Core 2 Errata -- problematic or overblown?philt2007/06/29 01:58 AM
              Core 2 Errata -- problematic or overblown?IlleglWpns2007/06/29 02:23 AM
                Core 2 Errata -- problematic or overblown?philt2007/06/29 08:16 PM
              Core 2 Errata -- problematic or overblown?Andi Kleen2007/06/29 04:36 AM
                Core 2 Errata -- problematic or overblown?philt2007/06/29 08:09 PM
                  Core 2 Errata -- problematic or overblown?Brendan2007/06/29 11:04 PM
                    Core 2 Errata -- problematic or overblown?philt2007/06/30 01:52 AM
                      Core 2 Errata -- problematic or overblown?Brendan2007/06/30 09:25 AM
                  Core 2 Errata -- problematic or overblown?Jukka Larja2007/06/29 11:22 PM
                  Core 2 Errata -- problematic or overblown?dan2007/07/05 12:36 PM
              Core 2 Errata -- problematic or overblown?Dean Kent2007/06/29 07:31 AM
                Core 2 Errata -- problematic or overblown?philt2007/06/29 07:57 PM
                  Core 2 Errata -- problematic or overblown?Dean Kent2007/06/29 08:50 PM
                    Core 2 Errata -- problematic or overblown?philt2007/06/30 01:57 AM
                      Core 2 Errata -- problematic or overblown?Dean Kent2007/06/30 05:34 AM
                        Core 2 Errata -- problematic or overblown?philt2007/07/02 03:33 AM
                          Core 2 Errata -- problematic or overblown?Dean Kent2007/07/02 05:36 AM
                            Core 2 Errata -- problematic or overblown?philt2007/07/02 03:02 PM
                              Core 2 Errata -- problematic or overblown?JS2007/07/02 10:02 PM
                      Core 2 Errata -- problematic or overblown?David Kanter2007/07/02 03:20 PM
            Core 2 Errata -- problematic or overblown?Max2007/06/29 11:23 AM
        Core 2 Errata -- problematic or overblown?Rob Thorpe2007/06/29 06:15 AM
          Core 2 Errata -- problematic or overblown?Michael S2007/06/29 06:57 AM
    Core 2 Errata -- problematic or overblown?jozzete2007/06/29 12:54 AM
  Core 2 Errata -- problematic or overblown?Brendan2007/06/28 07:15 PM
    Core 2 Errata -- problematic or overblown?france2007/06/28 10:38 PM
  Core 2 Errata -- problematic or overblown?rwessel2007/06/29 03:20 AM
    Core 2 Errata -- problematic or overblown?jschlossel2007/06/29 10:16 AM
      Core 2 Errata -- problematic or overblown?Dean Kent2007/06/29 10:25 AM
        Core 2 Errata -- problematic or overblown?Howard Chu2007/06/30 05:09 AM
          Core 2 Errata -- problematic or overblown?JS2007/07/02 04:58 AM
      baby and bath waterrels2007/06/30 07:00 AM
      Planes, trains and cars...Anna N.2007/07/01 06:28 PM
        Planes, trains and cars...David W. Hess2007/07/01 07:40 PM
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