Re: [RFC PATCH 0/4]: affinity-on-next-touch

[Stefan Lankes <lankes@lfbs.rwth-aachen.de>]

Brice Goglin wrote:
> Lee Schermerhorn wrote:
>> The primary difference should be at unmap time, right?  In the fault
>> path, I only update the pte of the faulting task.  That's why I require
>> the [anon] pages to be in the swap cache [or something similar].  I
>> don't want to be fixing up other tasks' page tables in the context of
>> the faulting task's fault handler.  If, later, another task touches the
>> page, it will take a minor fault and find the [possibly migrated] page
>> in the cache.  Hmmm, I guess all tasks WILL incur the minor fault if
>> they touch the page after the unmap.  That could be part of the
>> difference if you compare on the same kernel version.
>>   
> 
> Agreed.
> 
>> Try booting with cgroup_disable=memory on the command line, if you have
>> the memory resource controller configured in.  See what that does to
>> your measurements.
>>   
> 
> It doesn't seem to help. I'll try to bisect and find where the
> performance dropped.
> 

I am not able to reconstruct any performance drawbacks on my system. 
Could you send me your low-level benchmark?

Stefan