Re: [Qemu-devel] Re: [PATCH v2] qemu-kvm: Speed up of the dirty-bitmap-traveling

[Alexander Graf]

On 17.02.2010, at 10:42, OHMURA Kei wrote:

>>>> "We think"? I mean - yes, I think so too. But have you actually measured 
>>>> it?
>>>> How much improvement are we talking here?
>>>> Is it still faster when a bswap is involved?
>>> Thanks for pointing out.
>>> I will post the data for x86 later.
>>> However, I don't have a test environment to check the impact of bswap.
>>> Would you please measure the run time between the following section if 
>>> possible?
>> It'd make more sense to have a real stand alone test program, no?
>> I can try to write one today, but I have some really nasty important bugs to 
>> fix first.
> 
> 
> OK.  I will prepare a test code with sample data.  Since I found a ppc 
> machine around, I will run the code and post the results of
> x86 and ppc.
> 
> 
> By the way, the following data is a result of x86 measured in QEMU/KVM.  
> This data shows, how many times the function is called (#called), runtime of 
> original function(orig.), runtime of this patch(patch), speedup ratio (ratio).

That does indeed look promising!

Thanks for doing this micro-benchmark. I just want to be 100% sure that it 
doesn't affect performance for big endian badly.


Alex