Re: [Qemu-devel] Reporting Heisenbugs in qemu

[Paolo Bonzini <pbonzini@redhat.com>]

Il 08/05/2013 00:57, Aurelien Jarno ha scritto:
> On Tue, May 07, 2013 at 11:29:20PM +0200, Artyom Tarasenko wrote:
>> On Tue, May 7, 2013 at 1:38 PM, Torbjorn Granlund <tg@gmplib.org> wrote:
>>> The 2nd table of http://gmplib.org/devel/testsystems.html shows all
>>> emulated systems I am using, most of which are qemu-based.
>>
>> Do I read it correct that qemu-system-ppc64 with the slowdown factor
>> of 33 is ~3 times faster than qemu-system-sparc64 with the slowdown
>> factor of 96 ?
>> Do they both use Debian Wheezy guest? You have a remark that ppc64 has
>> problems with its clock. Was it taken into account when the slowdown
>> factors were calculated?
>>
> 
> Clock or not, it should be noted that qemu-system-sparc64 is undoubtedly
> slower (at least 5 to 10 times) than qemu-system-{arm,ppc,mips,...} on
> some type of load like perl scripts.

I guess that's the register windows.  There's only so much you can do to
optimize them, and heavily recursive workloads (like Perl, or the RTL
half of GCC) pay a hefty price.

Paolo