[ltt-dev] [RFC PATCHv2 4/5] urcu: re-implment urcu-qsbr

[Lai Jiangshan]

On 08/25/2011 04:35 PM, Paolo Bonzini wrote:
> On 08/25/2011 10:00 AM, Lai Jiangshan wrote:
>>> >I was measuring with 10 readers, not 3.  It makes sense to wait more with fewer readers.
>>
>> But my box just has 4 cores(i5 760).
> 
> You cannot be always sure that readers are less than the cores.  readers > cores is exactly the case when busy waiting hurts most.
> 


It makes no sense to do a "readers > cores" *performance* rcutorture test.
When "readers > cores", the kernel scheduler will mess the test up.

Thanks,
Lai.