From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <4B118F5B-8C82-4A47-AD79-30E4FEC96D5B@fastmail.fm> From: Ethan Grammatikidis To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> In-Reply-To: <000201cadd8d$14126ec0$3c374c40$@gmail.com> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v936) Date: Sat, 17 Apr 2010 00:10:45 +0100 References: <003201cadd83$81a9e5d0$84fdb170$@gmail.com> <2AE2F180-399F-4134-8755-300332DA7231@fastmail.fm> <000201cadd8d$14126ec0$3c374c40$@gmail.com> Subject: Re: [9fans] Recommended emulators/VMs for P9 install Topicbox-Message-UUID: 052ebd9e-ead6-11e9-9d60-3106f5b1d025 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