Re: [Qemu-devel] Debian 7.8.0 SPARC64 on qemu - anything i can do to speedup the emulation?

[Aurelien Jarno <aurelien@aurel32.net>]

On 2015-07-30 11:35, Artyom Tarasenko wrote:
> On Thu, Jul 30, 2015 at 10:55 AM, Aurelien Jarno <aurelien@aurel32.net> wrote:
> > On 2015-07-30 10:16, Dennis Luehring wrote:
> >> Am 30.07.2015 um 09:52 schrieb Aurelien Jarno:
> >> >On 2015-07-30 05:52, Dennis Luehring wrote:
> >> >> Am 29.07.2015 um 17:01 schrieb Aurelien Jarno:
> >> >> >The point is that emulation has a cost, and it's quite difficult to
> >> >> >to lower it and thus improve the emulation speed.
> >> >>
> >> >> so its just not strange for you to see an 1/100...200 of the native x64
> >> >> speed under qemu/SPARC64
> >> >> i hoped that someone will jump up an shout "its impossible - it needs to be
> >> >> a bug" ...sadly not
> >> >
> >> >Overall the ratio is more around 10, but in some specific cases where
> >> >the TB cache is inefficient and TB can't be linked or with an
> >> >inefficient MMU, a ratio of 100 is possible.
> >>
> >>
> >> sysbench (0.4.12) --num-threads=1 --test=cpu --cpu-max-prime=2000 run
> >>    Host x64    :   1.3580s
> >>    Qemu SPARC64: 184.2532s
> >>
> >> sysbench shows nearly ration of 200
> >
> > Note that when you say SPARC64 here, it's actually only the kernel, you
> > are using a 32-bit userland. And that makes a difference. Here are my
> > tests here:
> >
> > host (x86-64)                    0.8976s
> > sparc32 guest (sparc64 kernel)  99.6116s
> > sparc64 guest (sparc64 kernel)   4.4908s
> 
> Wow. That's quite a difference. What have you used as a sparc64 guest?
> Are there any ready-to-use distributions, or have you built it from scratch?

I am using Debian SPARC64 from debian-ports. But it's not really
ready-to-use and often broken.

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net