Why not enable highmem (4GB) on 32 bit systems?

Wilco · 2008-11-09 13:40:26

Hi all,

I have 4GB ram in my computer and only 3GB is visible in arch32. Sure, I can address the whole 4GB with arch64 but then I miss some software, like flash and wine.

Why isn't highmem64 enabled for 32 bits system? It seems (I'm not sure about this) like the overhead is zero on systems with less than 4GB and it should also work on 32 bit systems.

Anyone?

elmer_42 · 2008-11-09 14:54:06

I'm not entirely sure on this, but even if highmem is enabled, 32bit applications can only use the max for a 32bit OS.

Barrucadu · 2008-11-09 15:13:20

You can use flash and WINE in Arch64

vkumar · 2008-11-09 15:49:03

Or recompile your kernel with highmem support.

(If elmer_42 is right, then just disregard this!)

Wilco · 2008-11-09 16:43:07

But you can still use 4GB in 32 bits linux. Besides, highmem doesn't add a lot to the kernel, so why not?

Ranguvar · 2008-11-09 16:46:56

Highmem slows down your PC somewhat.

Anonymo · 2008-11-09 16:49:25

Anonymo Gates wrote:

Nobody will ever need more than 3 GB of RAM!

AndyRTR · 2008-11-09 17:53:26

Search our bugtracker. We tried to enable it and some drivers got broken when I rememeber right. So we reverted it.

jelly · 2008-11-09 19:36:52

you can use 4 Gb of ram with a 32bits kernel if you have PXE support

SomeGuyDude · 2008-11-09 21:07:27

Barrucadu wrote:

You can use flash and WINE in Arch64

Flash in Arch64 requires some pretty ugly workarounds, and I haven't seen a successful guide to getting Wine working (though someone on here said they'd done it).

skottish · 2008-11-09 21:14:45

SomeGuyDude wrote:

Barrucadu wrote:
You can use flash and WINE in Arch64
Flash in Arch64 requires some pretty ugly workarounds, and I haven't seen a successful guide to getting Wine working (though someone on here said they'd done it).

There's a modern guide here right now on how to install Flash 10 on 64 bit:

http://bbs.archlinux.org/viewtopic.php?id=58041

It's not as pretty as "pacman -S flashplugin", but it is easy and there are no ugly workarounds. Once Flash is set up, getting Wine set up is a matter of a few more packages which Wine is more than happy to complain about the first time winecfg is run.

Damnshock · 2008-11-09 21:29:15

2^32 = 4gb of adreces in a simple instruction. That's the maximum a 32bit processor can manage memory *directly*.

Of course, there are other ways to manage memory which will enable a 32 bits system to work with more than 4gigs of ram but they will slow down your system ( how much depends on the aproach).

Anyway, this is in theory and I don't really know how linux addresses memory. Maybe linux kind of "hides" a part of your system memory and that's why some are saying that you won't see the 4gb of ram. I don't know that well linux, don't think it is this way though. Probably your system will manage perfectly 4gb of ram without a problem

Damnshock

PS: enabling the 64gb support on a 32bits system *will* slow down the system, don't do it if you don't have more than 4gigs

arew264 · 2008-11-11 04:12:24

I run Arch64. I have Wine. I just installed it, there wasn't anything crazy about it. I think it's a 32 bit version, but who cares? Everything I want to run is 32 bit anyway.
Flash, yes, that works too.

The only piece of software I've had issues with was tigcc, a c compiler for the TI-89 calculator. That WOULD work on linux, but I'd have to compile it instead of using the binary version, which would require me to have all sorts of fun with PKGBUILD's to set up temporary bootstrap compilers and...
Someday I'll get that working, but for now I'm too lazy.

fukawi2 · 2008-11-11 04:33:59

I've just recompiled my kernel to enable PAE and 64G... So far haven't noticed and ill-effects or noticeable slowdown

Barrucadu · 2008-11-11 07:48:10

SomeGuyDude wrote:

Barrucadu wrote:
You can use flash and WINE in Arch64
Flash in Arch64 requires some pretty ugly workarounds, and I haven't seen a successful guide to getting Wine working (though someone on here said they'd done it).

http://wiki.archlinux.org/index.php/Ins … _on_Arch64

pacman -S bin32-wine

bin32-wine is in the archlinux.fr repo.

Wilco · 2008-11-11 09:39:04

fukawi2 wrote:

I've just recompiled my kernel to enable PAE and 64G... So far haven't noticed and ill-effects or noticeable slowdown

That's what I noticed too, no slowdowns whatsoever.

RedShift · 2008-11-13 09:14:56

Just because you don't notice it doesn't mean it's not there. Extra processor cycles are going to the page mapping tables which lead to a loss of performance. And just because you don't have any problems with it, doesn't mean someone else won't.

So if you really want to use PAE then just keep using your own kernel.

Damnshock · 2008-11-13 09:36:48

RedShift wrote:

Just because you don't notice it doesn't mean it's not there. Extra processor cycles are going to the page mapping tables which lead to a loss of performance. And just because you don't have any problems with it, doesn't mean someone else won't.
So if you really want to use PAE then just keep using your own kernel.

+1

fukawi2 · 2008-11-13 23:09:06

RedShift wrote:

Just because you don't notice it doesn't mean it's not there. Extra processor cycles are going to the page mapping tables which lead to a loss of performance. And just because you don't have any problems with it, doesn't mean someone else won't.
So if you really want to use PAE then just keep using your own kernel.

*shrugs* If I don't notice, then I don't really care (not on a desktop / laptop anyway).

Because I don't have any problems with it, someone else might not either

arew264 · 2008-11-14 00:52:40

Barrucadu wrote:

SomeGuyDude wrote:
Barrucadu wrote:
You can use flash and WINE in Arch64
Flash in Arch64 requires some pretty ugly workarounds, and I haven't seen a successful guide to getting Wine working (though someone on here said they'd done it).
http://wiki.archlinux.org/index.php/Ins … _on_Arch64
pacman -S bin32-wine
bin32-wine is in the archlinux.fr repo.

Yep, I'm using that repo and...

[arew264@Reno ~]$ sudo pacman -Q | grep wine
bin32-wine 1.1.7-1
[arew264@Reno ~]$

pyther · 2008-11-17 16:59:34

Its about time!!!! Now I can finally give-up ndiswrapper!!!! Yeah!!!!! I think this deserves to be a separate post!!!!

Dieter@be · 2008-11-17 17:04:27

pyther wrote:

Its about time!!!! Now I can finally give-up ndiswrapper!!!! Yeah!!!!! I think this deserves to be a separate post!!!!

There is one already !!!!!!!!!! Look on the forums !!!!!!!!! No need to make a new one !!!!!!!!!

pyther · 2008-11-17 21:46:05

My bad, I was at school, so I didn't have a chance browse all the forums and topics.

damjan · 2008-11-18 01:55:49

How about installing a 64bit kernel on your 32bit Arch distro.. That's what Theodore Tso uses (read it for the rationale).

Allan · 2008-11-18 03:09:59

damjan wrote:

How about installing a 64bit kernel on your 32bit Arch distro.. That's what Theodore Tso uses (read it for the rationale).

I have actually thought about doing this because my main machine is i686 (laptop, Core2Duo + 2Gb RAM) but I would like a x86_64 chroot for package building. But I am too busy/lazy to actually try...

Arch Linux

#1 2008-11-09 13:40:26

Why not enable highmem (4GB) on 32 bit systems?

#2 2008-11-09 14:54:06

Re: Why not enable highmem (4GB) on 32 bit systems?

#3 2008-11-09 15:13:20

Re: Why not enable highmem (4GB) on 32 bit systems?

#4 2008-11-09 15:49:03

Re: Why not enable highmem (4GB) on 32 bit systems?

#5 2008-11-09 16:43:07

Re: Why not enable highmem (4GB) on 32 bit systems?

#6 2008-11-09 16:46:56

Re: Why not enable highmem (4GB) on 32 bit systems?

#7 2008-11-09 16:49:25

Re: Why not enable highmem (4GB) on 32 bit systems?

#8 2008-11-09 17:53:26

Re: Why not enable highmem (4GB) on 32 bit systems?

#9 2008-11-09 19:36:52

Re: Why not enable highmem (4GB) on 32 bit systems?

#10 2008-11-09 21:07:27

Re: Why not enable highmem (4GB) on 32 bit systems?

#11 2008-11-09 21:14:45

Re: Why not enable highmem (4GB) on 32 bit systems?

#12 2008-11-09 21:29:15

Re: Why not enable highmem (4GB) on 32 bit systems?

#13 2008-11-11 04:12:24

Re: Why not enable highmem (4GB) on 32 bit systems?

#14 2008-11-11 04:33:59

Re: Why not enable highmem (4GB) on 32 bit systems?

#15 2008-11-11 07:48:10

Re: Why not enable highmem (4GB) on 32 bit systems?

#16 2008-11-11 09:39:04

Re: Why not enable highmem (4GB) on 32 bit systems?

#17 2008-11-13 09:14:56

Re: Why not enable highmem (4GB) on 32 bit systems?

#18 2008-11-13 09:36:48

Re: Why not enable highmem (4GB) on 32 bit systems?

#19 2008-11-13 23:09:06

Re: Why not enable highmem (4GB) on 32 bit systems?

#20 2008-11-14 00:52:40

Re: Why not enable highmem (4GB) on 32 bit systems?

#21 2008-11-17 16:59:34

Re: Why not enable highmem (4GB) on 32 bit systems?

#22 2008-11-17 17:04:27

Re: Why not enable highmem (4GB) on 32 bit systems?

#23 2008-11-17 21:46:05

Re: Why not enable highmem (4GB) on 32 bit systems?

#24 2008-11-18 01:55:49

Re: Why not enable highmem (4GB) on 32 bit systems?

#25 2008-11-18 03:09:59

Re: Why not enable highmem (4GB) on 32 bit systems?

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