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On Mon, 08 Dec 2008 13:31:27 +0000, Invisible wrote:
> http://xkcd.com/456/
>
> Mmm... I did this.
>
> Do you have *any idea* how long it takes to compile the Linux kernel?
It depends.
On a lot of things, like how fast your system is, whether it's multi-core
(if made with -j that will do parallel compilation, speeding things up a
bit), how much memory you have, how fast your disk I/O channel is, memory
channel, etc.
> I
> mean, damn, how *big* is it??
It depends.
On a lot of things, like which modules you compile into the kernel,
compile as kernel modules, or don't compile. Also on which options you
actually enable.
> I thought the final binary was only a few
> KB in size...
It depends.
On my 64-bit system, the kernel is about 2.1 MB in size, but that doesn't
include 108 MB of modules for this specific kernel.
> Oddly, X11 also takes forever.
It's a lot of code, video drivers for many different types of cards.
> (It's no surprise however that Firefox and OpenOffice are slow as hell.
> Oh, and KDE... *very* slow!)
>
> Damn, I really don't know why the hell I did that...
Well, now you've learned something - LFS does take time. :-)
Jim
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On Mon, 08 Dec 2008 14:00:24 +0000, Invisible wrote:
> Kyle wrote:
>> That's funny. Been there.
>
> "...I'm too late." ;-)
>
>>> Do you have *any idea* how long it takes to compile the Linux kernel?
>>> I mean, damn, how *big* is it?? I thought the final binary was only a
>>> few KB in size...
>>
>> The wait is even more fun the second time around, after you realize you
>> forgot to configure a necessary driver into your custom kernel. :D
>
> I still don't entirely "get" why you would ever recompile the OS kernel.
> I mean, all it does is memory allocation, interrupt scheduling, etc.
> What's to change?
Driver support beyond what's in your shipping kernel.
> Also... Gentoo is the only Linux distro I've ever seen where compiling
> the kernel was actually successful. Every other distro managed to either
> spit cryptic error messages at me, or just leave me with a nonbootable
> system.
Well, I've compiled on RedHat and on openSUSE, as well as having
installed Slackware and Linux From Scratch and compiled kernels for them.
Try LFS, that'll really teach you a lot about linux, even if you don't
get a bootable system.
Jim
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On Mon, 08 Dec 2008 13:45:55 -0200, Nicolas Alvarez wrote:
> Invisible wrote:
>> (It's no surprise however that Firefox and OpenOffice are slow as hell.
>> Oh, and KDE... *very* slow!)
>
> Compiling all of KDE using GCC 3 == PAIN
Building GCC on Sun systems was fun - IIRC, it compiled itself three
times, first time using the commercial compiler that came with the OS,
and then two separate passes with GCC itself to optimize its own code.
Jim
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Invisible wrote:
>
> I still don't entirely "get" why you would ever recompile the OS kernel.
> I mean, all it does is memory allocation, interrupt scheduling, etc.
> What's to change?
>
1) Upgrade.
2) Add support to stuff (eg. new devices)
-Aero
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Invisible wrote:
>
> Indeed yes.
>
> Since even quite "large" programs take only a few seconds to compile,
> the Linux kernel must be *huge*...
So POV-Ray is much more than large? The machine I compiled it earlier
with is equipped with AMD Athlon64 X2 4450e ie. 2,3GHz dual-core, 64-bit
Athlon and 8GiB of memory. It's not the fastest machine on Earth, but I
wouldn't call it a slow one either (yet, after a year or two I'll
probably do that).
>> OpenOffice takes couple of hours IIRC.
>
> ...and OpenOffice must be absolutely gigantic.
Yes, it is a mammoth.
grunka ~ # du -hs /var/tmp/portage/app-office/openoffice-3.0.0/work/ooo/
2.6G /var/tmp/portage/app-office/openoffice-3.0.0/work/ooo/
> But then, it's a pretty
> complex bit of software, so you'd expect that. The Linux kernel's job
> seems quite a bit simpler by comparison.
Errrr... It's not that simple. Try and make similar thing yourself.
btw:
grunka src # du -hs linux-2.6.26-gentoo-r4/
316M linux-2.6.26-gentoo-r4/
That is non-compiled, non-configured set, ie. just kernel sources
equipped with Gentoo's patchset. So yes, it is huge :).
>> Linux kernel inholds
>> drivers for most of the hardware you're using (possibly even all of
>> them), does memory allocating, process handling, networking,
>> firewalling, RAID-handling, even cryptographic thingies.
>
> Ah yes, I'm forgetting: The Linux "kernel" isn't just the OS kernel. How
> silly of me...
Linux kernel is a monolithic kernel, not a microkernel.
http://en.wikipedia.org/wiki/Microkernel
http://en.wikipedia.org/wiki/Monolithic_kernel
> (It probably contains drivers for every piece of hardware known to
> mankind, even if you don't need it. And I'll bet even if you disable
> those parts, it still has to process that part of the source code to
> decide whether or not to compile it...)
No, it doesn't :(. That's one reason why Windows is still much more
widely used in workstations and especially in gaming computers.
I dunno exactly what the system checks from the source when I leave eg.
floppy disk driver out, but it does make the whole process faster.
-Aero
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Mueen Nawaz wrote:
>
> 8-10 minutes is not that long. I've been running Gentoo for over 5
> years on the same machine, so I can tell you how long it took for any
> package I've ever compiled via Portage.
Ooh, I've clearly missed some information, where is that written?
-Aero
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Jim Henderson wrote:
> On Mon, 08 Dec 2008 14:00:24 +0000, Invisible wrote:
>
>> Kyle wrote:
>>> That's funny. Been there.
>> "...I'm too late." ;-)
>>
>>>> Do you have *any idea* how long it takes to compile the Linux kernel?
>>>> I mean, damn, how *big* is it?? I thought the final binary was only a
>>>> few KB in size...
>>> The wait is even more fun the second time around, after you realize you
>>> forgot to configure a necessary driver into your custom kernel. :D
>> I still don't entirely "get" why you would ever recompile the OS kernel.
>> I mean, all it does is memory allocation, interrupt scheduling, etc.
>> What's to change?
>
> Driver support beyond what's in your shipping kernel.
>
>> Also... Gentoo is the only Linux distro I've ever seen where compiling
>> the kernel was actually successful. Every other distro managed to either
>> spit cryptic error messages at me, or just leave me with a nonbootable
>> system.
>
> Well, I've compiled on RedHat and on openSUSE, as well as having
> installed Slackware and Linux From Scratch and compiled kernels for them.
>
> Try LFS, that'll really teach you a lot about linux, even if you don't
> get a bootable system.
>
> Jim
It's not too hard to get a bootable LFS system - and if it is hard and
you get it to boot, then you've learned a lot!
I must admit, I cheat and use the automated build now days.
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Jim Henderson wrote:
> On Mon, 08 Dec 2008 13:31:27 +0000, Invisible wrote:
>
>> http://xkcd.com/456/
>>
>> Mmm... I did this.
>>
>> Do you have *any idea* how long it takes to compile the Linux kernel?
>
> It depends.
>
> On a lot of things, like how fast your system is, whether it's multi-core
> (if made with -j that will do parallel compilation, speeding things up a
> bit), how much memory you have, how fast your disk I/O channel is, memory
> channel, etc.
>
>> I
>> mean, damn, how *big* is it??
>
> It depends.
>
> On a lot of things, like which modules you compile into the kernel,
> compile as kernel modules, or don't compile. Also on which options you
> actually enable.
>
>> I thought the final binary was only a few
>> KB in size...
>
> It depends.
>
> On my 64-bit system, the kernel is about 2.1 MB in size, but that doesn't
> include 108 MB of modules for this specific kernel.
>
>> Oddly, X11 also takes forever.
>
> It's a lot of code, video drivers for many different types of cards.
>
>> (It's no surprise however that Firefox and OpenOffice are slow as hell.
>> Oh, and KDE... *very* slow!)
>>
>> Damn, I really don't know why the hell I did that...
>
> Well, now you've learned something - LFS does take time. :-)
>
> Jim
Hey Jim, sounds like you are into the LFS stuff as well.
I'm going through the book "Building Embedded Linux Systems" and they
refer to CLFS quite a bit. Seems like those guys made the earth move a
bit -;)
Tom
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Jim Henderson wrote:
> Building GCC on Sun systems was fun - IIRC, it compiled itself three
> times, first time using the commercial compiler that came with the OS,
> and then two separate passes with GCC itself to optimize its own code.
Yep, the three-phase bootstrapping. I think the final step is building
itself with itself and comparing both executables, to make sure everything
worked.
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>> Building GCC on Sun systems was fun - IIRC, it compiled itself three
>> times, first time using the commercial compiler that came with the OS,
>> and then two separate passes with GCC itself to optimize its own code.
>
> Yep, the three-phase bootstrapping. I think the final step is building
> itself with itself and comparing both executables, to make sure everything
> worked.
I understand the Haskell compiler (GHC) does something similar. First,
you obtain a copy of GHC compiled into ANSI C. Then you use that to
compile the original Haskell source code for GHC.
The fun part, of course, as that was well as a working Haskell compiler,
you need a working Haskell runtime engine and a set of working Haskell
base libraries (which hook directly into the runtime and are partly
hard-wired into the compiler)... ;-)
Apparently building GHC is... nontrivial. And poorly-documented.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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