Re: [9fans] Recommended emulators/VMs for P9 install

[Ethan Grammatikidis <eekee57@fastmail.fm>]

On 16 Apr 2010, at 18:48, Patrick Kelly wrote:

>>>
>>> The only emulator you're spending time on is Qemu, the rest are
>>> virtualizers or simulators, and there is a significant difference.
>>> Emulators are much slower, because of what they have to do.
>>
>> Qemu is capable of full emulation, but when host & guest
>> architecture match (or are compatible, e.g. x86_32 guest and x86_64
>> host)
>> it's a virtualizer. Given x86 on x86, there is a world of
>> difference between Bochs's performance and Qemu's.
>
> It's mostly full and not completely accurate.
> I don't use Qemu so this may be wrong, but I was under the
> impression Qemu was an emulator unless you used kqemu, and then it
> lost emulation capability's.

It can virtualise better with kqemu or kvm, but... well, perhaps I
should say what I know rather than try to categorise. Take 3 set-ups.
A: arm guest, x86 host. Full emulation, kqemu cannot be used. B: x86
guest, x86 host without kqemu. C: x86 guest, x86 host with kqemu.
There is a much bigger performance gap between A and B than between B
and C.

>
>> Qemu's display is slow, whatever other factors exist. Drawterm to a
>> qemu cpu server is very much faster. I can't speak for disk IO
>> except to say it seems fast under my light usage.
>>
>> Also, to nit-pick, don't all virtualisers emulate peripheral
>> hardware?
>
> For peripheral hardware, emulators and virtualizers are mostly the
> same, but that isn't the main reason most people use them, it's
> about the execution environment, which involves how the CPU is
> handled. Seeing as you didn't bring up a single full system
> emulator, I doubt you care more about peripherals.

*nods* Not a big point for me right now.

>
>

--
Simplicity does not precede complexity, but follows it. -- Alan Perlis