qemu on a recent -current, slow like a 486 !

[Bruce Cran]

Doug Kelly wrote:
> On Sep 2, 2007, at 10:56 PM, Nenhum_de_Nos wrote:
>
>> hail,
>>
>> I have a Turion X2 1.8GHz and created a SMP 64bits VM just for running
>> folding at home. I'm now compiling linux kernel source for gentoo
>> distro, and it takes a century for each module (.o) to be compiled.
>>
>> FreeBSD xxx.apartnet 7.0-CURRENT FreeBSD 7.0-CURRENT #0: Thu Aug  9
>> 01:44:04 BRT 2007     root at xxx.apartnet:/usr/obj/usr/src/sys/xxx  i386
>>
>> and
>>
>> QEMU PC emulator version 0.9.0, Copyright (c) 2003-2007 Fabrice Bellard
>>
>> any more info, just ask ...
>>
>> is it always this slow ?!
>
> Well, I know -CURRENT's kernel has a ton of debug options enabled by 
> default, which will adversely impact performance.  You can disable 
> them in the kernel's config file (you'll need to rebuild the kernel, 
> though), and the GENERIC config has some notes about them.  Also, qemu 
> is a full emulator--although there is a kernel module for Linux to 
> allow some type of virtualization, I'm not sure if it's been ported to 
> any other OSes.
>
> In short, yes, it will be slow.  I'm sure "a century" is hyperbole, 
> but yes, even though you are on a rather fast machine, it will be 
> slow, as every single instruction on your qemu VM is going to be 
> emulated.

The kernel module to speed up execution of the x86 emulation on x86 
platforms is available in the emulators/kqemu-kmod port.

--
Bruce Cran