Core 2 Errata -- problematic or overblown?

By: Linus Torvalds (torvalds.delete@this.osdl.org), June 28, 2007 8:30 am
Room: Moderated Discussions
Rob Thorpe (rthorpe@realworldtech.com) on 6/28/07 wrote:
>
>Well, most other CPUs are embedded ones.

Well, I'd call those "commodity", wouldn't you? Even more
so than x86.

That said, a lot of them are quite buggy. The way the
embedded people define it, though, any bugs becomes just
"specifications".

For example, the ARM cache control has always been pretty
damn buggy. What is the solution? Document it as a bug,
and tell people not to use it.

Or grep for "errata" in arch/arm in the Linux kernel. Trust
me, they exist.

But yeah, you can make a microcontroller CPU that is based
on some decade-old core that is fairly bug-free. Not that
it probably really is, but over the years the bugs have all
become "behavior" rather than "bugs".

>Whether other higher-end CPUs have more errata than x86s
>I don't know.

They tend to fix the bugs that are user-visible, and then
not fix the bugs that can be worked around on an OS
level.

Also, boutique vendors tend to not talk about them,
because it's all internal to their own stuff. Of course, if
they don't catch it in time, they'll have to release OS
upgrades, but if they find an errata early, they can just
work around it and need never tell anybody, exactly like
the random embedded ones.

It's really simple: when you count your CPU's in thousands
rather than millions, you generally don't want to do a whole
new mask set that costs you months and a few megabucks. It's
much cheaper to just ship the buggy crud.

Yeah, x86 errata get more attention. But those things are
pretty damn well tested. Better than most. And since the OS
is outside the control of the vendors, they get fixed too.

Linus
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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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