[PATCH 0/2] Faster MMU lookups for Book3s v3

[Alexander Graf]

On 01.07.2010, at 09:29, Avi Kivity wrote:

> On 06/30/2010 04:18 PM, Alexander Graf wrote:
>> Book3s suffered from my really bad shadow MMU implementation so far. So
>> I finally got around to implement a combined hash and list mechanism that
>> allows for much faster lookup of mapped pages.
>> 
>> To show that it really is faster, I tried to run simple process spawning
>> code inside the guest with and without these patches:
>> 
>> [without]
>> 
>> debian-powerpc:~# time for i in {1..1000}; do /bin/echo hello>  /dev/null; done
>> 
>> real    0m20.235s
>> user    0m10.418s
>> sys     0m9.766s
>> 
>> [with]
>> 
>> debian-powerpc:~# time for i in {1..1000}; do /bin/echo hello>  /dev/null; done
>> 
>> real    0m14.659s
>> user    0m8.967s
>> sys     0m5.688s
>> 
>> So as you can see, performance improved significantly.
>> 
>> v2 ->  v3:
>> 
>>   - use hlist
>>   - use global slab cache
>> 
>>   
> 
> Looks good.

Great :).

How does dirty bitmap flushing work on x86 atm? I loop through all mapped pages and flush the ones that match the range of the region I need to flush. But wouldn't it be a lot more efficient to have an hlist in the memslot and loop through that when I need to flush that memslot?

Alex