Re: [Qemu-devel] [Qemu-ppc] [PATCH RFC v1 0/3] Enable MTTCG on PPC64

[G 3 <programmingkidx@gmail.com>]

On Apr 6, 2017, at 9:32 AM, Cédric Le Goater wrote:

> On 04/06/2017 03:28 PM, G 3 wrote:
>>
>> On Apr 6, 2017, at 9:26 AM, Cédric Le Goater wrote:
>>
>>> Hello Nikunj,
>>>
>>> On 04/06/2017 12:22 PM, Nikunj A Dadhania wrote:
>>>> The series enables Multi-Threaded TCG on PPC64
>>>>
>>>> Patch 01: Use atomic_cmpxchg in store conditional
>>>>       02: Handle first write to page during atomic operation
>>>>       03: Generate memory barriers for sync/isync and load/store  
>>>> conditional
>>>>
>>>> Patches are based on ppc-for-2.10
>>>>
>>>> Tested using following:
>>>> ./ppc64-softmmu/qemu-system-ppc64 -cpu POWER8 -vga none - 
>>>> nographic -machine pseries,usb=off -m 2G  -smp  
>>>> 8,cores=8,threads=1 -accel tcg,thread=multi  f23.img
>>>
>>> I tried it with a Ubuntu 16.04.2 guest using stress --cpu 8. It  
>>> looked
>>> good : the CPU usage of QEMU reached 760% on the host.
>>
>> What was your guest operating system?
>
> The guest is an Ubuntu 16.04.2 and the host is an Ubuntu 17.04.
>
> C.

Thank you for the information.

What you could do is run QEMU in emulation mode (non-kvm mode) and  
time how long it takes Ubuntu to boot up with one emulated core vs  
how long it takes to boot up on say 4 emulated cores. This would be a  
good start:

Boot up times:

one core:

two cores:

four cores:

eight cores: