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

[Alexander Graf]

Anthony Liguori wrote:
> On 02/10/2010 07:20 AM, Avi Kivity wrote:
>   
>> On 02/10/2010 12:52 PM, OHMURA Kei wrote:
>>   
>>     
>>> dirty-bitmap-traveling is carried out by byte size in qemu-kvm.c.
>>> But We think that dirty-bitmap-traveling by long size is faster than by byte
>>> size especially when most of memory is not dirty.
>>>
>>> --- a/bswap.h
>>> +++ b/bswap.h
>>> @@ -209,7 +209,6 @@ static inline void cpu_to_be32wu(uint32_t *p, uint32_t 
>>> v)
>>>  #define cpu_to_32wu cpu_to_le32wu
>>>  #endif
>>>  
>>> -#undef le_bswap
>>>  #undef be_bswap
>>>  #undef le_bswaps
>>>   
>>>     
>>>       
>> Anthony, is it okay to export le_bswap this way, or will you want
>> leul_to_cpu()?
>>   
>>     
>
> kvm_get_dirty_pages_log_range() is kvm-specific code. We're guaranteed
> that when we're using kvm, target byte order == host byte order.
>
> So is it really necessary to use a byte swapping function at all?
>   

On PPC the bitmap is Little Endian.


Alex