Re: [Qemu-devel] [RFC] find_next_bit optimizations

[Peter Lieven]

Am 12.03.2013 um 09:35 schrieb Stefan Hajnoczi <address@hidden>:

> On Mon, Mar 11, 2013 at 02:44:03PM +0100, Peter Lieven wrote:
>> I ever since had a few VMs which are very hard to migrate because of a lot 
>> of memory I/O. I found that finding the next dirty bit
>> seemed to be one of the culprits (apart from removing locking which Paolo is 
>> working on).
>> 
>> I have to following proposal which seems to help a lot in my case. Just 
>> wanted to have some feedback.
> 
> Hi Peter,
> Do you have any performance numbers for this patch?  I'm just curious
> how big the win is.

Hi Stefan,

please see my recent email to the list with the final patch.
The win is up to 100%. Worst case execution time (whole
array is zero) is halved on x86_64.

Peter

> 
> Stefan