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 rumorsmas2007/05/05 12:59 PM
  Rock/Tukwila rumorsDavid Kanter2007/05/05 02:33 PM
    Rock/Tukwila rumorsDean Kent2007/05/05 03:35 PM
      K8 vs Win64 timelineanonymous2007/05/05 06:19 PM
        Yes, I misremembered...Dean Kent2007/05/05 10:03 PM
    RockDaniel Bizó2007/05/06 02:34 AM
      RockDean Kent2007/05/06 07:11 AM
    Rock/Tukwila rumorsJoe2007/05/06 11:24 AM
      Rock/Tukwila rumorsDean Kent2007/05/06 11:49 AM
      Rock/Tukwila rumorsLinus Torvalds2007/05/06 12:09 PM
      Rock/Tukwila rumorsanon2007/05/07 01:32 AM
        Rock/Tukwila rumorsRakesh Malik2007/05/07 09:36 AM
          Rock/Tukwila rumorsMichael S2007/05/07 10:06 AM
          Rock/Tukwila rumorsanon2007/05/07 09:48 PM
            Rock/Tukwila rumorsRakesh Malik2007/05/08 06:45 AM
              Rock/Tukwila rumorsanon2007/05/08 05:30 PM
                Wow. (nt)Brannon2007/05/08 06:16 PM
                Rock/Tukwila rumorsrwessel2007/05/08 09:48 PM
                  Rock/Tukwila rumorsJS2007/05/08 10:07 PM
                    Rock/Tukwila rumorsJS2007/05/09 06:44 AM
                Rock/Tukwila rumorsRakesh Malik2007/05/09 05:35 AM
                  Much ado about xMichael S2007/05/09 09:39 AM
                    Call it x86-64Linus Torvalds2007/05/09 10:27 AM
                      (i)AMD64Michael S2007/05/09 12:16 PM
                        (i)AMD64Linus Torvalds2007/05/09 12:29 PM
                          (i)AMD64Groo2007/05/09 04:45 PM
                          TIFNAAanonymous2007/05/09 05:49 PM
                            Inspired by FYR Macedonia? (NT)Michael S2007/05/09 11:21 PM
                              More likely...rwessel2007/05/10 12:39 AM
                            TIFNAAGabriele Svelto2007/05/09 11:57 PM
                          (i)AMD64James2007/05/10 02:27 AM
                        i86Dean Kent2007/05/09 12:30 PM
                        (i)AMD64Max2007/05/09 01:28 PM
                          wide86? long86?hobold2007/05/10 05:05 AM
                            x87 perhaps, it is one more. :) (NT)Groo2007/05/10 05:50 AM
                              x86+Dean Kent2007/05/10 08:44 AM
                                Does it really matter?Doug Siebert2007/05/10 09:10 AM
                                  let's stay with x86-64 for now, pleaseMarcin Niewiadomski2007/05/10 11:50 AM
                                    let's stay with x86-64 for now, pleaseDean Kent2007/05/11 06:11 AM
                                      let's stay with x86-64 for now, pleaserwessel2007/05/11 02:46 PM
                                        let's stay with x86-64 for now, pleaseDean Kent2007/05/11 06:03 PM
                                          let's stay with x86-64 for now, pleaseMichael S2007/05/12 10:49 AM
                                            let's stay with x86-64 for now, pleaseDean Kent2007/05/12 01:05 PM
                                              let's stay with x86-64 for now, pleaseMichael S2007/05/12 01:25 PM
                                                let's stay with x86-64 for now, pleaseDean Kent2007/05/12 03:39 PM
                                                  let's stay with x86-64 for now, pleaseJasonB2007/05/13 07:43 AM
                                                    client consolidationMichael S2007/05/13 08:37 AM
                                                  let's stay with x86-64 for now, pleaseTzvetan Mikov2007/05/13 03:44 PM
                                                let's stay with x86-64 for now, pleaserwessel2007/05/14 02:42 PM
                                      What's your point?Doug Siebert2007/05/11 02:56 PM
                                        What's your point?Linus Torvalds2007/05/11 04:15 PM
                                          What's your point?Doug Siebert2007/05/13 03:11 PM
                                            What's your point?Dean Kent2007/05/13 07:04 PM
                                              What's your point?JasonB2007/05/14 02:06 AM
                                                What's your point?Dean Kent2007/05/14 07:20 AM
                                                  What's your point?JasonB2007/05/14 04:35 PM
                                                  What's your point?JasonB2007/05/14 07:35 PM
                                                    What's your point?Dean Kent2007/05/14 08:12 PM
                                        What's your point?Dean Kent2007/05/11 06:06 PM
                                        What's your point?Stephen H2007/05/13 01:55 AM
                                          Why didn't MS take advantage of PAE?David W. Hess2007/05/13 08:37 AM
                                            PAE sucks (Why didn't MS take advantage of PAE?)Linus Torvalds2007/05/13 10:20 AM
                                              PAE sucks (Why didn't MS take advantage of PAE?)Dean Kent2007/05/13 10:49 AM
                                              PAE sucks (Why didn't MS take advantage of PAE?)David W. Hess2007/05/13 12:37 PM
                                              > 1 GB RAM on a 32-bit systemTzvetan Mikov2007/05/13 01:44 PM
                                                > 1 GB RAM on a 32-bit systemS. Rao2007/05/13 03:00 PM
                                                  > 1 GB RAM on a 32-bit systemTzvetan Mikov2007/05/13 05:32 PM
                                                    > 1 GB RAM on a 32-bit systemS. Rao2007/05/14 12:19 AM
                                                > 1 GB RAM on a 32-bit systemLinus Torvalds2007/05/13 03:46 PM
                                                  > 1 GB RAM on a 32-bit systemTzvetan Mikov2007/05/13 05:23 PM
                                                  > 1 GB RAM on a 32-bit systemJasonB2007/05/13 06:37 PM
                                                    Windows manages memory differentlyTzvetan Mikov2007/05/13 08:31 PM
                                                      Windows manages memory differentlyJasonB2007/05/14 01:50 AM
                                                        Windows manages memory differentlyTzvetan Mikov2007/05/14 08:56 AM
                                                          Windows manages memory differentlyrwessel2007/05/14 03:40 PM
                                                            Windows manages memory differentlyDavid W. Hess2007/05/14 04:07 PM
                                                              Windows manages memory differentlyrwessel2007/05/14 04:51 PM
                                                            Windows manages memory differentlyTzvetan Mikov2007/05/14 05:40 PM
                                                              Windows manages memory differentlyrwessel2007/05/14 06:09 PM
                                                      Windows manages memory differentlyHoward Chu2007/05/14 11:17 AM
                                                        Windows manages memory differentlyJukka Larja2007/05/14 11:30 AM
                                                        Windows manages memory differentlyTzvetan Mikov2007/05/14 01:54 PM
                                                          Windows manages memory differentlyHoward Chu2007/05/15 03:35 AM
                                                            Windows manages memory differentlyGroo2007/05/15 07:34 AM
                                                      Anyone know what OS X (10.4, Intel, desktop) does?Matt Sayler2007/05/15 06:23 AM
                                                        Anyone know what OS X (10.4, Intel, desktop) does?Wes Felter2007/05/15 08:37 AM
                                                        Anyone know what OS X (10.4, Intel, desktop) does?Anonymous2007/05/15 10:49 AM
                                                        Anyone know what OS X (10.4, Intel, desktop) does?anon22007/05/15 07:13 PM
                                              PAE sucks (Why didn't MS take advantage of PAE?)Paul2007/05/13 03:40 PM
                                                PAE sucks (Why didn't MS take advantage of PAE?)Peter Arremann2007/05/13 05:38 PM
                                                  PAE sucks (Why didn't MS take advantage of PAE?)Henrik S2007/05/14 03:31 AM
                                              The fragility of your argumentslacker2007/05/13 03:56 PM
                                                The fragility of your argumentnick2007/05/13 05:42 PM
                                                The fragility of your argumentHoward Chu2007/05/14 02:52 AM
                                                  The fragility of your argumentDean Kent2007/05/14 09:19 AM
                                                The fragility of your argumentanon22007/05/14 08:26 AM
                                                  The fragility of your argumentTzvetan Mikov2007/05/14 09:01 AM
                                                  The fragility of your argumentDean Kent2007/05/14 09:16 AM
                                                    The fragility of your argumentLinus Torvalds2007/05/14 11:57 AM
                                                      The fragility of your argumentJasonB2007/05/14 04:48 PM
                                                        The fragility of your argumentDean Kent2007/05/14 07:36 PM
                                                          The fragility of your argumentRicardo B2007/05/16 02:40 AM
                                                            The fragility of your argumentDean Kent2007/05/16 03:32 AM
                                                              The fragility of your argumentRicardo B2007/05/16 06:41 AM
                                                                PSRicardo B2007/05/16 06:50 AM
                                                                The fragility of your argumentDean Kent2007/05/16 09:07 AM
                                                                  Modern web browsingS. Rao2007/05/16 09:16 AM
                                                                    Aha!Dean Kent2007/05/16 09:27 AM
                                                                      Aha!Dean Kent2007/05/16 09:32 AM
                                                                        Aha!S. Rao2007/05/16 10:34 AM
                                                                  The fragility of your argumentRicardo B2007/05/16 10:00 AM
                                                      The fragility of your argumentVincent Diepeveen2007/05/16 10:10 AM
                                                        The fragility of your argumentPaul2007/05/16 03:01 PM
                                                          The fragility of your argumentVincent Diepeveen2007/05/17 03:05 AM
                                                    The fragility of your argumentanon22007/05/15 01:35 AM
                                                    Splits vs page allocations?Matt Sayler2007/05/15 07:33 AM
                                          What's your point?Michael S2007/05/13 08:55 AM
                                            What's your point?anonymous2007/05/13 11:08 AM
                                              What's your point?Michael S2007/05/13 11:31 AM
                                      let's stay with x86-64 for now, pleaseJasonB2007/05/13 07:16 AM
                                x864 =) (NT)some12007/05/15 03:03 AM
    Rock/Tukwila rumorsIntelUser20002007/05/06 02:27 PM
  Rock/Tukwila rumorsm2007/05/13 08:05 AM
  Rock/Tukwila rumorsmas2007/05/15 09:40 AM
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