Rock/Tukwila rumors

By: Linus Torvalds (torvalds.delete@this.osdl.org), May 6, 2007 12:09 pm
Room: Moderated Discussions
Joe (uh@no.way) on 5/6/07 wrote:
>
>Yeah, which is why Apple had a 64bit version of OSX ready
>to go as soon as they were shipping x64-capable Macs.
>
>Oh, wait.

Yeah. Great example.

There's a big difference between

"In theory you can take advantage of being single-
platform and controlling the whole stack"

and

"In practice, that just means that you don't get the
flexibility and capabilities of a wider range of hw
and usage"

and I have yet ever to see an environment where
specialization actually generated a better system.

Yes, Linux is portable, and yes, that effectively means
that core functionality does not necessarily support some
hardware-specific feature in a very integral manner. And
in theory, an operating system that can afford to integrate
the random feature of today very deeply into it could make
it more "natural".

But in practice, we've never had any real trouble with
allowing hardware capabilities to be exposed, even if they
may not be exposed as core functionality. Are you
on an x86 with magic support for virtualization? We can use
the hardware, even if not every other platform (or even
most x86 chips) actually supports that feature.

In fact, portability has in general meant that Linux has
been able to take advantage of new hardware features much
better than nonportable operating systems, exactly
because Linux doesn't make deep assumptions about
the architecture in core code. That really cuts both ways:
it very much means that new features that perhaps break
old assumptions are easier to integrate, because those old
assumptions weren't deeply encoded in some very core data
structure etc.

The 64-bit thing is an excellent example of this. Linux
was already very aware of the fact that data structures can
have different endianness and size, and so it was much
easier to move over.

But it goes deeper than that. Look at something like Cell:
where the cores are fundamentally different, but since the
"core" OS doesn't make tons of assumptions, and already has
abstracted out a lot of CPU details, we already had a lot
of the infrastructure in place for abstracting all of the
CPU details, and as a result it's not at all impossible in
theory to use the same scheduler with per-CPU queues to
schedule totally different kinds of CPU's using the same
core code!

IOW, portability is actually really hard but it also
actually does end forcing you to write better code! It's
taken us a long time to get there, but we've also had a lot
more resources than some piddling little company like Apple
(or even microsoft) can afford to put on something like a
core kernel!

Linus
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TopicPosted ByDate
Rock/Tukwila rumorsmas05/05/07 12:59 PM
  Rock/Tukwila rumorsDavid Kanter05/05/07 02:33 PM
    Rock/Tukwila rumorsDean Kent05/05/07 03:35 PM
      K8 vs Win64 timelineanonymous05/05/07 06:19 PM
        Yes, I misremembered...Dean Kent05/05/07 10:03 PM
    RockDaniel Biz√≥05/06/07 02:34 AM
      RockDean Kent05/06/07 07:11 AM
    Rock/Tukwila rumorsJoe05/06/07 11:24 AM
      Rock/Tukwila rumorsDean Kent05/06/07 11:49 AM
      Rock/Tukwila rumorsLinus Torvalds05/06/07 12:09 PM
      Rock/Tukwila rumorsanon05/07/07 01:32 AM
        Rock/Tukwila rumorsRakesh Malik05/07/07 09:36 AM
          Rock/Tukwila rumorsMichael S05/07/07 10:06 AM
          Rock/Tukwila rumorsanon05/07/07 09:48 PM
            Rock/Tukwila rumorsRakesh Malik05/08/07 06:45 AM
              Rock/Tukwila rumorsanon05/08/07 05:30 PM
                Wow. (nt)Brannon05/08/07 06:16 PM
                Rock/Tukwila rumorsrwessel05/08/07 09:48 PM
                  Rock/Tukwila rumorsJS05/08/07 10:07 PM
                    Rock/Tukwila rumorsJS05/09/07 06:44 AM
                Rock/Tukwila rumorsRakesh Malik05/09/07 05:35 AM
                  Much ado about xMichael S05/09/07 09:39 AM
                    Call it x86-64Linus Torvalds05/09/07 10:27 AM
                      (i)AMD64Michael S05/09/07 12:16 PM
                        (i)AMD64Linus Torvalds05/09/07 12:29 PM
                          (i)AMD64Groo05/09/07 04:45 PM
                          TIFNAAanonymous05/09/07 05:49 PM
                            Inspired by FYR Macedonia? (NT)Michael S05/09/07 11:21 PM
                              More likely...rwessel05/10/07 12:39 AM
                            TIFNAAGabriele Svelto05/09/07 11:57 PM
                          (i)AMD64James05/10/07 02:27 AM
                        i86Dean Kent05/09/07 12:30 PM
                        (i)AMD64Max05/09/07 01:28 PM
                          wide86? long86?hobold05/10/07 05:05 AM
                            x87 perhaps, it is one more. :) (NT)Groo05/10/07 05:50 AM
                              x86+Dean Kent05/10/07 08:44 AM
                                Does it really matter?Doug Siebert05/10/07 09:10 AM
                                  let's stay with x86-64 for now, pleaseMarcin Niewiadomski05/10/07 11:50 AM
                                    let's stay with x86-64 for now, pleaseDean Kent05/11/07 06:11 AM
                                      let's stay with x86-64 for now, pleaserwessel05/11/07 02:46 PM
                                        let's stay with x86-64 for now, pleaseDean Kent05/11/07 06:03 PM
                                          let's stay with x86-64 for now, pleaseMichael S05/12/07 10:49 AM
                                            let's stay with x86-64 for now, pleaseDean Kent05/12/07 01:05 PM
                                              let's stay with x86-64 for now, pleaseMichael S05/12/07 01:25 PM
                                                let's stay with x86-64 for now, pleaseDean Kent05/12/07 03:39 PM
                                                  let's stay with x86-64 for now, pleaseJasonB05/13/07 07:43 AM
                                                    client consolidationMichael S05/13/07 08:37 AM
                                                  let's stay with x86-64 for now, pleaseTzvetan Mikov05/13/07 03:44 PM
                                                let's stay with x86-64 for now, pleaserwessel05/14/07 02:42 PM
                                      What's your point?Doug Siebert05/11/07 02:56 PM
                                        What's your point?Linus Torvalds05/11/07 04:15 PM
                                          What's your point?Doug Siebert05/13/07 03:11 PM
                                            What's your point?Dean Kent05/13/07 07:04 PM
                                              What's your point?JasonB05/14/07 02:06 AM
                                                What's your point?Dean Kent05/14/07 07:20 AM
                                                  What's your point?JasonB05/14/07 04:35 PM
                                                  What's your point?JasonB05/14/07 07:35 PM
                                                    What's your point?Dean Kent05/14/07 08:12 PM
                                        What's your point?Dean Kent05/11/07 06:06 PM
                                        What's your point?Stephen H05/13/07 01:55 AM
                                          Why didn't MS take advantage of PAE?David W. Hess05/13/07 08:37 AM
                                            PAE sucks (Why didn't MS take advantage of PAE?)Linus Torvalds05/13/07 10:20 AM
                                              PAE sucks (Why didn't MS take advantage of PAE?)Dean Kent05/13/07 10:49 AM
                                              PAE sucks (Why didn't MS take advantage of PAE?)David W. Hess05/13/07 12:37 PM
                                              > 1 GB RAM on a 32-bit systemTzvetan Mikov05/13/07 01:44 PM
                                                > 1 GB RAM on a 32-bit systemS. Rao05/13/07 03:00 PM
                                                  > 1 GB RAM on a 32-bit systemTzvetan Mikov05/13/07 05:32 PM
                                                    > 1 GB RAM on a 32-bit systemS. Rao05/14/07 12:19 AM
                                                > 1 GB RAM on a 32-bit systemLinus Torvalds05/13/07 03:46 PM
                                                  > 1 GB RAM on a 32-bit systemTzvetan Mikov05/13/07 05:23 PM
                                                  > 1 GB RAM on a 32-bit systemJasonB05/13/07 06:37 PM
                                                    Windows manages memory differentlyTzvetan Mikov05/13/07 08:31 PM
                                                      Windows manages memory differentlyJasonB05/14/07 01:50 AM
                                                        Windows manages memory differentlyTzvetan Mikov05/14/07 08:56 AM
                                                          Windows manages memory differentlyrwessel05/14/07 03:40 PM
                                                            Windows manages memory differentlyDavid W. Hess05/14/07 04:07 PM
                                                              Windows manages memory differentlyrwessel05/14/07 04:51 PM
                                                            Windows manages memory differentlyTzvetan Mikov05/14/07 05:40 PM
                                                              Windows manages memory differentlyrwessel05/14/07 06:09 PM
                                                      Windows manages memory differentlyHoward Chu05/14/07 11:17 AM
                                                        Windows manages memory differentlyJukka Larja05/14/07 11:30 AM
                                                        Windows manages memory differentlyTzvetan Mikov05/14/07 01:54 PM
                                                          Windows manages memory differentlyHoward Chu05/15/07 03:35 AM
                                                            Windows manages memory differentlyGroo05/15/07 07:34 AM
                                                      Anyone know what OS X (10.4, Intel, desktop) does?Matt Sayler05/15/07 06:23 AM
                                                        Anyone know what OS X (10.4, Intel, desktop) does?Wes Felter05/15/07 08:37 AM
                                                        Anyone know what OS X (10.4, Intel, desktop) does?Anonymous05/15/07 10:49 AM
                                                        Anyone know what OS X (10.4, Intel, desktop) does?anon205/15/07 07:13 PM
                                              PAE sucks (Why didn't MS take advantage of PAE?)Paul05/13/07 03:40 PM
                                                PAE sucks (Why didn't MS take advantage of PAE?)Peter Arremann05/13/07 05:38 PM
                                                  PAE sucks (Why didn't MS take advantage of PAE?)Henrik S05/14/07 03:31 AM
                                              The fragility of your argumentslacker05/13/07 03:56 PM
                                                The fragility of your argumentnick05/13/07 05:42 PM
                                                The fragility of your argumentHoward Chu05/14/07 02:52 AM
                                                  The fragility of your argumentDean Kent05/14/07 09:19 AM
                                                The fragility of your argumentanon205/14/07 08:26 AM
                                                  The fragility of your argumentTzvetan Mikov05/14/07 09:01 AM
                                                  The fragility of your argumentDean Kent05/14/07 09:16 AM
                                                    The fragility of your argumentLinus Torvalds05/14/07 11:57 AM
                                                      The fragility of your argumentJasonB05/14/07 04:48 PM
                                                        The fragility of your argumentDean Kent05/14/07 07:36 PM
                                                          The fragility of your argumentRicardo B05/16/07 02:40 AM
                                                            The fragility of your argumentDean Kent05/16/07 03:32 AM
                                                              The fragility of your argumentRicardo B05/16/07 06:41 AM
                                                                PSRicardo B05/16/07 06:50 AM
                                                                The fragility of your argumentDean Kent05/16/07 09:07 AM
                                                                  Modern web browsingS. Rao05/16/07 09:16 AM
                                                                    Aha!Dean Kent05/16/07 09:27 AM
                                                                      Aha!Dean Kent05/16/07 09:32 AM
                                                                        Aha!S. Rao05/16/07 10:34 AM
                                                                  The fragility of your argumentRicardo B05/16/07 10:00 AM
                                                      The fragility of your argumentVincent Diepeveen05/16/07 10:10 AM
                                                        The fragility of your argumentPaul05/16/07 03:01 PM
                                                          The fragility of your argumentVincent Diepeveen05/17/07 03:05 AM
                                                    The fragility of your argumentanon205/15/07 01:35 AM
                                                    Splits vs page allocations?Matt Sayler05/15/07 07:33 AM
                                          What's your point?Michael S05/13/07 08:55 AM
                                            What's your point?anonymous05/13/07 11:08 AM
                                              What's your point?Michael S05/13/07 11:31 AM
                                      let's stay with x86-64 for now, pleaseJasonB05/13/07 07:16 AM
                                x864 =) (NT)some105/15/07 03:03 AM
    Rock/Tukwila rumorsIntelUser200005/06/07 02:27 PM
  Rock/Tukwila rumorsm05/13/07 08:05 AM
  Rock/Tukwila rumorsmas05/15/07 09:40 AM
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